<PAGE>













                                 EXHIBIT 10.40

<PAGE>
CONFIDENTIAL TREATMENT HAS        **Confidential treatment has been requested
BEEN REQUESTED FOR CERTAIN          with respect to the information contained
PORTIONS OF THIS DOCUMENT             within the "[**]" markings. Such marked
                                  portions have been omitted from this filing
                                      and have been filed separately with the
                                           Securities and Exchange Commission


                    WORLDWIDE TECHNOLOGY LICENSE AGREEMENT
                    --------------------------------------

     This Agreement, dated December 27, 1996 (the "SIGNATURE DATE") is made
between Premisys Communications, Inc. ("PREMISYS"), a Delaware corporation
doing business at 48664 Milmont Drive, Fremont, California 94538, and Positron
Fiber Systems Corporation ("POSITRON"), a corporation organized under the laws
of Canada doing business at 5101 Buchan Street, Montreal, Quebec, Canada
H4P2R9.

                                   RECITALS

     A.   Positron designs and markets SONET based products used in
telecommunications networks and systems and has expertise in designing SONET
and SDH based integrated circuits and backplanes and related software which is
considered proprietary and has rights to certain integrated circuit and
backplane technology, software and related documentation.

     B.   Premisys designs and markets products used in telecommunications
networks and systems and desires to purchase such expertise and rights from
Positron.

     C.   Premisys and Positron wish to have Positron license such expertise
and technology to Premisys and assist Premisys in incorporating Positron's
integrated circuit, backplane and software technologies into Premisys products
which, for a period of time, will not compete with current Positron products as
specified herein and to have Positron grant Premisys world-wide rights to
manufacture, market and distribute Premisys products incorporating Positron's
integrated circuit, backplane and software technologies.

     D.   Premisys intends to develop and market products incorporating
Positron's SONET and SDH technology which, for a limited period of time, will
be different from, and not directly competitive with, Positron's current OSIRIS
products as specified herein.

     Positron and Premisys agree as follows:

     1.   DEFINITIONS.

          1.1  "ASIC" means the application specific integrated circuits listed
in EXHIBIT A attached hereto, any bug fix made to the ASIC in any form and
provided to any Positron customer during the term of this Agreement, and any
update or upgrade necessary to ensure compliance with the Standards.

          1.2  "ASIC FABRICATOR" means [
**] and any other ASIC manufacturer that manufactures, has manufactured or will
manufacture the ASICs for Positron.

          1.3  "ASLC MANUFACTURING MATERIALS" means all specifications,
netlists, test vectors and other information related to the ASICs and any other
information necessary or useful to allow the ASIC Fabricator to manufacture and
test the ASICs, except portions, if any, owned by the ASIC Fabricator.

          1.4  "BACKPLANE" means the backplane listed on EXHIBIT A attached
hereto, any bug fix made available in any form to any Positron customer during
the term of this Agreement.

          1.5  "BACKPLANE DEVELOPMENT MATERIALS" means all printed circuit
board schematics, Specifications, drawings and bills of materials for the
Backplane.


<PAGE>

          1.3  "ASLC MANUFACTURING MATERIALS" means all specifications,
netlists, test vectors and other information related to the ASICs and any other
information necessary or useful to allow the ASIC Fabricator to manufacture and
test the ASICs, except portions, if any, owned by the ASIC Fabricator.
          
          1.4  "BACKPLANE" means the backplane listed on EXHIBIT A attached
hereto, any bug fix made available in any form to any Positron customer during
the term of this Agreement.
          
          1.5  "BACKPLANE DEVELOPMENT MATERIALS" means all printed circuit
board schematics, Specifications, drawings and bills of materials for the
Backplane.
          
          1.6  "DESIGN DOCUMENTATION" means:
(a)  all board level schematics for the most current version of all Positron
OC3-STM-1 based OSIRIS products which utilize or incorporate any ASIC, FPGA or
Backplane on the date the corresponding Design Documentation is to be delivered
to Premisys;
(b)  for ASICs, FPGAs and Backplane which are not used in any board level
schematic described in Section 1.6(a), example board level schematics which
incorporate, and correctly and fully show the operation of, such ASICs, FPGAs
and Backplane in a product Positron is developing, and explanatory text; and
(c)  a bill of material for, and approved vendor list for each component on,
any schematic set forth in Sections 1.6(a) and (b).
          
          1.7  "DESIGN SOURCE MATERIALS" means the VHDL and other source code
and related libraries, schematics, layouts, design notes and other information
useful or required for the design or modification the ASICs, FPGAs and
Backplane, including but not limited to the ASIC Escrow Materials and the FPGA
Escrow Materials set forth in EXHIBIT D attached hereto, excluding
Specifications, the ASIC Manufacturing Materials, the FPGA Manufacturing
Materials and the Backplane Development Materials.
          
          1.8  "END USER" means a direct or indirect customer of Premisys who
purchases Premisys Products for the End User's business purposes.
          
          1.9  "EFFECTIVE DATE" means the date following the Signature Date on
which Premisys provides written acceptance of all required governmental
approvals provided by Positron, pursuant to Section 14.1 of this Agreement.
          
          l.10 "FPGA" means the programmed field programmable gate arrays
listed in EXHIBIT A attached hereto, any bug fix made available in any form to
any Positron customer during the term of this Agreement, and any update or
upgrade necessary to ensure compliance with the Standards.


                                      2
<PAGE>

          1.11 "FPGA MANUFACTURING MATERIALS" means all information
necessary or helpful to manufacture and test each of the FPGAs, including but
not limited to programming data, ".fus" files, ".def" files, ".als" files and
".bat" files to operate the FPGA manufacturing environment set forth in EXHIBIT
E attached hereto.
          
          1.12 "INTELLECTUAL PROPERTY RIGHTS" means patent rights,
copyright rights (including, but not limited to, rights in audiovisual works
and moral rights), trade secret rights, and any other intellectual property
rights recognized by the law of each applicable jurisdiction.
          
          1.13 "LICENSED TECHNOLOGY" means the ASICs, FPGAs, Backplane and
Software.
          
          1.14 "LICENSED MANUFACTURING MATERIALS" means the ASIC
Manufacturing Materials and the FPGA Manufacturing Materials.
          
          1.15 "MODIFIED BACKPLANE" means a new version of the Backplane
designed by Premisys that is based upon the Backplane for use in Premisys
Products.
          
          1.16 "MODIFIED BACKPLANE MANUFACTURING MATERIALS" means all
printed circuit board schematics, drawings, bills of material and any other
materials necessary or useful for the manufacture of Modified Backplanes based
on the Backplane Development Materials.
          
          1.17 "PREMISYS PRODUCTS" means any telecommunications product
distributed by Premisys which contains or includes some or all of the Licensed
Technology or one or more Modified Backplanes.
          
          1.18 "SOFTWARE" means all of the system and driver software related
to the ASICs, FPGAs or Backplane in object code and source code formats, and
all documentation related to such software, including but not limited to the
software and related documentation specified in EXHIBIT A, any bug fixes
related to the ASICs, FPGAs, Backplane or Software made available in any form
to any Positron customer during the term of this Agreement, and all upgrades
and updates necessary to ensure interoperability with the Licensed Technology
and Backplanes provided hereunder and to ensure compliance with the Standards.
          
          1.19 "SPECIFICATIONS" means all specifications, including but
not limited to functional descriptions, user specifications, software interface
specifications, input-output specifications, application notes, test
specifications and design specifications for the Licensed Technology to be
delivered by Positron to Premisys as set forth in EXHIBIT B.
          
          1.20 "STANDARDS" means, on the Effective Date, the standards
described in EXHIBIT G attached hereto identified therein with the word,
"comply" and additionally, upon the date that Positron ships any Licensed
Technology to any Positron customer that complies with any standard described
in EXHIBIT G identified therein with the word, "future," such future standard.


                                      3
<PAGE>
          
          1.21 "SUBDISTRIBUTOR" means a direct or indirect customer of
Premisys who is authorized by Premisys to distribute Premisys Products to End
Users or other Subdistributors.
     
     2.   LICENSES, PRICING AND PURCHASE.
          
          2.1  LICENSE GRANTS.
               
               (a)  DEVELOPMENT LICENSE.  Subject to the terms of this
Agreement, Positron grants Premisys a worldwide license to: (i) use, reproduce,
modify and create derivative works based upon, the Specifications and Design
Documentation in order to develop Premisys Products; (ii) use the
Specifications for the Software and to use, modify and compile source code and
object code versions of the Software in order to develop Premisys Products and
create derivative works of the Software; and (iii) use, reproduce, modify and
create derivative works based upon, the Backplane Development Materials to
develop Modified Backplane Manufacturing Materials, Modified Backplanes and
other Premisys Products.
               
               (b)  MANUFACTURING AND REPRODUCTION LICENSE.  Subject to the
terms of this Agreement, Positron grants Premisys a worldwide license to: (i)
use the Licensed Manufacturing Materials to have the ASICs manufactured and to
make and have made the FPGAs solely and exclusively for incorporation into
Premisys Products for distribution in accordance with Section 2.1(c); (ii) use
the Modified Backplane Manufacturing Materials to make and have made Modified
Backplanes solely and exclusively for incorporation into Premisys Products for
distribution in accordance with Section 2.1(c); and (iii) reproduce and have
reproduced the Software solely and exclusively for the purpose of development
of Premisys Products in accordance with Section 2.1(a) and to reproduce and
have reproduced object code versions of the Software and derivative works
thereof solely and exclusively for the purpose of distribution in accordance
with Section 2.1(c). Positron will direct all ASIC Fabricators to manufacture
the ASICs for Premisys as Premisys requires and at Premisys' expense.
               
               (c)  DISTRIBUTION LICENSE.  Subject to the terms of this
Agreement, Positron grants Premisys a worldwide license to: (i) market,
distribute, and sell Premisys Products to End Users, directly or indirectly
through Subdistributors; and (ii) market, distribute and sublicense to End
Users, object code versions of the Software and derivative works thereof,
directly or indirectly through Subdistributors.
               
               (d)  OPERATING SYSTEM, SOFTWARE INTEROPERATION. The Software and
any bug fixes, upgrades and updates as supplied by Positron to Premisys may use
application programming interfaces of the OS9 operating system commercially
available to Premisys from Microware. Should Premisys wish to use such OS9
operating system with the Software, Premisys must separately license such OS9
operating system from Microware. Positron may supply to Premisys certain bug
fixes, upgrades and updates to the Software which interoperate with Open
Systems Interconnect stacks and protocols in third party software provided such
third party software, is commercially available to Premisys. Should Premisys
wish to use such third party software, Premisys must separately license such
third party software from the applicable third party.  At the time Positron
provides such bug fixes, upgrades and updates of the Software


                                      4
<PAGE>

to Premisys, Positron will identify to Premisys any such stacks and 
protocols, and provide Premisys with the name, address and telephone number 
of such third party.
          
          2.2  EXCLUSIVITY.
               
               (a)  GRANT OF EXCLUSIVITY. During the period beginning on the
Effective Date and ending twelve (12) months from the Effective Date, Premisys
will have the exclusive right to use the Licensed Technology, ASIC
Manufacturing Materials, FPGA Manufacturing Materials, Software and Backplane
Development Materials, in whole or in part, and any Intellectual Property
Rights therein or derivative works based thereon in or for the development of
products that: (i) in Premisys' reasonable determination, compete with Premisys
IMACS products or any other Premisys Products that are being marketed by
Premisys during such twelve (12) month period; or (ii) comprise any Integrated
Access Device or Digital Subscriber Line Access Multiplexer, as such terms are
defined in Section 2.2(c) of this Agreement. The parties agree that any product
meeting Bellcore TR-909 Fiber to the Curb specification will not  be deemed to
be the type of product covered by Sections 2.2(a)(i) or 2.2(a)(ii) or the grant
of exclusivity under this Section 2.2(a).
               
               (b)  EXPIRATION OF EXCLUSIVITY. After the twelve (12) month
period set forth in Section 2.2(a), the licenses granted in Section 2.1 of this
Agreement will be nonexclusive.
               
               (c)  EXCLUSIVITY DEFINITIONS.  An "INTEGRATED ACCESS DEVICE" is
any device that can provide: (i) simultaneous termination of multiple types of
low speed (e.g. voice services, RS-232 asynchronous data, BRI-ISDN) and
wideband (e.g. V.35, DDS synchronized data, frame relay, ATM or PRI-ISDN)
services on a single platform; (ii) services interoperability (e.g. ISDN to
frame relay); or (iii) Class-5 voice switch terminations such as TR08 or multi-
wire analog tip and ring pairs. A "DIGITAL SUBSCRIBER LINE ACCESS MULTIPLEXER"
is any device that can provide: (i) support for the Bellcore GR-2842 Service
Access Multiplexer specification; (ii) simultaneous termination and aggregation
of low speed voice and high speed data; (iii) termination of derived telephony
"outside plant" loop pairs; (iv) simultaneous termination of POTS line circuits
with ADSL and other digital subscriber line interfaces; (v) simultaneous
termination of at least two types of low speed (e.g. voice services, RS-232
asynchronous data, BRI-ISDN) and wideband (e.g. V.35, DDS synchronized data,
frame relay, ATM or PRI-ISDN) services on a single platform; or (vi) services
interoperability (e.g. ISDN to frame relay).
          
          2.3  PRICING FREEDOM.  Premisys is, and will remain, entirely free to
determine its End User and Subdistributor prices and fees for Premisys Products
in its own discretion.
          
          2.4  PURCHASE OF ASICS.  At Premisys' option, Premisys may purchase
the ASICs from Positron at the lower of Positron's, or any Positron's
Affiliate's (as defined below), net cost of purchasing the ASICs plus ten
percent (10%) in addition to the payment of the initial payments and royalties
set forth in Section 5 of this Agreement, subject to other reasonable terms set
forth in a separate purchase agreement to be negotiated by the parties during
the thirty days following the Effective Date of this Agreement "POSITRON'S
AFFILIATE" means any entity that


                                      5
<PAGE>

effectively controls Positron, is under the effective control of
Positron, or any entity under the effective control of an entity which
effectively controls Positron.
     
     3.   LICENSE RESTRICTIONS.
          
          3.1  For a period of twenty four (24) months following the first
shipment to any Premisys customer of any of the Premisys Products, Premisys
will not  manufacture any Premisys Product that is specifically optimized for
Add/Drop Multiplexing (ADM) of DS3 (E3) and DS1 (E1) bandwidth onto SONET-OC3
(SDH-STM-1) facilities. A Premisys Product that is specifically optimized for
Add/Drop Multiplexing (ADM) of DS3 (E3) and DS1 (E1) bandwidth onto SONET-OC3
(SDH-STM-1) facilities is a Premisys Product which is not inherently capable,
via the system architecture, of terminating and/or processing DS0 (64 kilobits
per second) based channels, or processing DS1 (E1)/DS3 (E3) packet/cell based
channels. During such twenty four (24) month period, Premisys will always
install Premisys Products with the hardware necessary to terminate or process
either DS0 based channels or DS1 (E1) and/or DS3 (E3) packet/cell based
channels. Following such twenty-four month period, Premisys may manufacture
Premisys Products and install Premisys Products without the hardware necessary
to process either DS0 or DS1 (E1) and/or DS3 (E3) packet/cell based channels.
          
          3.2  NO SUB-LICENSING.  None of the Licensed Manufacturing Materials,
Backplane Development Materials, Software or Specifications or any derivative
works thereof may be sub-licensed by Premisys to any third-party other than as
an integrated part of a Premisys Product, without the express written agreement
of Positron.
          
          3.3  ADDED VALUE.  Premisys will only market and distribute the
Software for use with other software for Premisys Products.
          
          3.4  NO UNAUTHORIZED USE OF DESIGN DOCUMENTATION.  Design
Documentation are intended to provide design assistance to Premisys in
modifying the Backplane and Software and in incorporating the ASICs, FPGAs,
Modified Backplane and Software as modified into Premisys Products. Except as
set forth herein, Premisys has no license or implied right to disclose,
license, sell, provide or otherwise transfer the Design Documentation to any
third party.
     
     4.   DELIVERY.  Positron will deliver the Specifications, Software,
Licensed Manufacturing Materials, Design Documentation and Backplane
Development Materials to Premisys according to the Schedule attached hereto as
EXHIBIT B. Positron warrants that all existing ASIC Manufacturing Materials for
the ASICs have been delivered to GEC Plessey. Positron warrants that, for each
of the ASICs, all ASIC Manufacturing Materials will be delivered to the ASIC
Fabricator at the time that Positron delivers the related materials to Premisys
as set forth in EXHIBIT B attached hereto, and that at least sixty days prior
to such time, Positron will identify the ASIC Fabricator to Premisys in writing
if such ASIC Fabricator is not  GEC Plessey.
     
     5.   PAYMENTS.
          


                                      6
<PAGE>

          5.1  INITIAL PAYMENTS.  Premisys will pay Positron the initial
payments specified in Section C.1 of EXHIBIT C upon the occurrence of the
triggering events set forth in Section C.1 of EXHIBIT C.
          
          5.2  ROYALTIES.  During the term of this Agreement, Premisys will pay
Positron the royalties, less the deductions, set forth in Section C.2 of
EXHIBIT C for Premisys' shipment of the Premisys Products to any Premisys
customer. Premisys will make such payments within thirty (30) days after the
end of each calendar quarter in which Premisys receives payment from its
customer for such Premisys Products beginning with the quarter ending December
31, 1997.
          
          5.3  PAYMENT TERMS.  All payments under this Agreement will be made
in United States currency by Premisys company check, or by bank-to-bank wire
transfer to an account designated by Positron, unless otherwise agreed to by
the parties in writing.
     
     6.   REPORTS AND AUDITS.
          
          6.1  PREMISYS' RECORDS.  Premisys will maintain complete records,
during and for two (2) years after the termination or expiration of this
Agreement, regarding the distribution of the Premisys Products.
          
          6.2  PAYMENT REPORTS.  Within thirty (30) days after the close of
each calendar quarter ending March 31, June 30, September 30 and December 31,
Premisys will deliver to Positron a report which will provide all information
reasonably necessary for computation and/or confirmation of the payments, if
any, due or credited to Positron for such quarterly period.
          
          6.3  AUDIT.  Not  more than two times per calendar year during the
term of this agreement and for two years thereafter, an independent certified
public accountant selected by Positron may, upon reasonable notice and during
normal business hours, inspect the records of Premisys on which such reports
are based. If, upon performing such audit, it is determined that Premisys has
underpaid Positron by an amount greater than five percent (5%) of the payments
due Positron in the period being audited, Premisys will bear all reasonable
expenses and costs of such audit in addition to its obligation to make full
payment under Section 5.
     
     7.   MAINTENANCE, SUPPORT, AND TRAINING.
          
          7.1  BY PREMISYS.  Premisys will be responsible for providing the
following support to its End Users and Subdistributors: installing the Premisys
Products as needed; training End Users and Subdistributors; and providing all
technical support to End Users and Subdistributors, including but not limited
to diagnosing problems and using its reasonable efforts to provide solutions.
          
          7.2  BY POSITRON AT NO CHARGE.  During the term of this Agreement, at
no additional charge to Premisys, Positron will provide Premisys with:


                                      7
<PAGE>

               (a)  any error corrections or updates or upgrades which are
necessary to ensure compliance with the Standards, ensure interoperability
with, or to correct errors in, the Licensed Manufacturing Materials, Backplane
Development Materials, Specifications, Design Documentation and Software at
such time as Positron complies in any Positron product with any of the
Standards identified as "future" in EXHIBIT G, or at such time as such error
corrections, updates or upgrades are made available in any form to any Positron
customer but not  less than once per calendar year;
               
               (b)  reasonable telephone access to Positron's design engineers
for diagnosing design or documentation errors within the Licensed Technology
from Premisys design engineers related to the Licensed Technology or Software
or the corresponding Specifications, Licensed Manufacturing Materials or
Backplane Development Materials between the hours of 9 a.m. and 5 p.m., Eastern
Time, on Positron's business days;
               
               (c)  two hundred (200) person-hours per ASIC, FPGA and
Backplane, and sixteen (16) hours per error correction, upgrade or update of
the Licensed Technology or Software for training and design assistance
requested by Premisys to assist its personnel in incorporating the Licensed
Technology into the Premisys Products; and
               
               (d)  Documentation and Specifications will be delivered by
Positron to Premisys as set forth herein without any clarifications or
additions. Any clarifications and additions requested by Premisys will be
deemed design assistance for the purpose of Sections 7.2(c) or 7.3(a),
whichever is applicable at the time such request is performed by Positron.
          
          7.3  BY POSITRON AT STANDARD RATES.  For one hundred dollars ($100)
per person-hour plus reasonable travel expenses approved in writing in advance
by Premisys, upon request by Premisys, Positron will provide Premisys:
               
               (a)  additional training and design assistance beyond that
specified in Section 7.2(c) of this Agreement;
               
               (b)  ASIC Manufacturing Materials adapted to replace the ASIC
Fabricator in the event that Premisys develops a reasonable expectation that
the ASIC Fabricator will be unable to reasonably supply Premisys with ASICs in
the quantities and according to the schedule required by Premisys, or in the
event that Premisys is able to secure ASICs from another vendor for less than
seventy five percent (75%) of the price charged by the ASIC Fabricator,
provided that Premisys pays such vendor's NRE fees;
               
               (c)  FPGA Manufacturing Materials adapted to a manufacturing
environment different from the FPGA manufacturing environment set forth in
EXHIBIT E and/or a blank FPGA different from the blank FPGAs specified in
EXHIBIT E should such manufacturing environment or blank FPGA become
unavailable to Premisys in quantities and according to a schedule reasonably
acceptable to Premisys;


                                      8
<PAGE>
               
               (d)  new versions of the Licensed Manufacturing Materials,
Backplane Development Materials, Design Documentation, Software and
Specifications for ASICs, FPGAs, Backplanes or Software based on the Licensed
Technology as specified by Premisys; and
               
                (e) additional technology and assistance requested by 
Premisys to assist Premisys in integrating the Licensed Technology and 
Software into Premisys Products. Any development effort exceeding one hundred 
eighty (l80) man hours per ASIC, FPGA or Backplane to be performed under this 
Section 7.3 will be subject to a development supply agreement which will be 
negotiated in good faith and on terms mutually agreed upon by the parties.
          
          7.4  RESOLUTION OF CERTAIN DISPUTES.  In the event of any dispute or
disagreement between the parties with respect to whether a change requested by
Premisys is an error correction to be remedied by Positron pursuant to Section
7.2(a) of this Agreement, or a new version to be implemented by Positron
pursuant to Section 7.3(d) of this Agreement, each of the parties will appoint
a designated representative to meet for the purpose of resolving such dispute.
The parties will attempt in good faith to resolve the dispute. If the dispute
or disagreement cannot  be resolved by the parties, then binding arbitration
will be held. The rules of the arbitration will be agreed upon by the parties
prior to the arbitration. To the extent the parties cannot  agree on the rules
of the arbitration, the rules of the American Arbitration Association will
apply. As a minimum set of rules, the parties agree as follows:
               
               (a)  The arbitration will be held by a single arbitrator
mutually acceptable to both parties. If the parties cannot  agree on a single
arbitrator, each party will identify one independent individual who shall meet
to appoint a single arbitrator.
               
               (b)  The decision of the arbitrator will be considered as a
final and binding resolution of the disagreement which may be entered as a
judgment by any court of competent jurisdiction.
               
               (c)  The arbitration will be held m a mutually convenient site.
               
               (d)  Neither party will sue the other except for enforcement of
the arbitrator's decision.
     
     8.   CONFIDENTIALITY.
          
          8.1  OBLIGATIONS.  Each party agrees:
               
               (a)  that it will not  disclose to any third party or use the
business or technical information disclosed to it by the other party
(collectively, the "OTHER PARTY'S CONFIDENTIAL INFORMATION") except as
permitted in this Agreement; and
               
               (b)  that it will take all reasonable measures to maintain the
confidentiality of all of the Other Party's Confidential Information in its
possession or control,


                                      9
<PAGE>

which will in no event be less than the measures it uses to maintain the 
confidentiality of its own information of similar importance.
          
          8.2  EXCEPTIONS.  With respect to a party, the "OTHER PARTY'S 
CONFIDENTIAL INFORMATION" will not include information that:
               
               (a)  is in or enters the public domain without breach of this
Agreement;
               
               (b)  such party lawfully receives from a third party without
restriction on disclosure and without breach of a nondisclosure obligation; or
               
               (c)  such party develops independently or knew prior to the
Effective Date, unless covered by a prior confidentiality agreement between the
parties.
          
          8.3  CONFIDENTIALITY OF TERMS OF AGREEMENT.  Either party may
publicly announce the existence of this Agreement, the Licensed Technology and
Software covered by this Agreement and the term, but not  the other terms, of
this Agreement PROVIDED however that any news or press release must be approved
in writing and in advance of release by the other party, such approval not  to
be unreasonably withheld. Neither party may disclose the other terms of this
Agreement without the advance written permission of the other party, except as
required by judicial order, government rule or regulation, or to such party's
accountants, attorneys and advisors who are subject to reasonable
confidentiality obligations.
     
     9.   PROPRIETARY RIGHTS.
          
          9.1  POSITRON'S OWNERSHIP.  The Licensed Manufacturing Materials
Specifications, Design Source Materials, Backplane Development Materials,
Design Documentation and the Software are and will remain the sole and
exclusive property of Positron and its suppliers, if any, whether the Designs
and Layouts or the Software are separate or combined with any other products.
          
          9.2  PREMISYS OWNERSHIP.  The Premisys Products, excluding the
Licensed Technology, the Modified Backplane, any new and enhanced version of
the Software developed by or for Premisys, and the Modified Backplane
Manufacturing Materials are and will remain the sole and exclusive property of
Premisys and its suppliers, if any. Any suggested enhancement, improvement or
modification to the ASICs, FPGAs, Backplane or Software originally invented,
and proposed to Positron, by Premisys, and any derivative work of the Software
that is made, or proposed, by Premisys will be the sole and exclusive property
of Premisys, and Positron hereby assigns to Premisys all right, title and
interest only in such enhancement, improvement, modification and derivative
work, provided that Premisys pays Positron for the development fees set forth
in Section 7.3(e) of this Agreement requested by Positron, and Premisys pays
Positron the applicable initial payment specified in Section C.1 of EXHIBIT C
for such ASIC, FPGA or Backplane.
     

                                      10
<PAGE>

     10.  ESCROW.
          
          10.1 ESCROW ACCOUNT.  Within thirty (30) days after the Effective
Date, Positron and Premisys will enter into a reasonable and customary source
code escrow agreement containing terms and conditions reasonably agreeable to
the parties with a mutually agreed, recognized, independent third party escrow
agent in the United States (the "ESCROW AGENT"), and such agreement will be
negotiated in good faith by Positron and Premisys. Under such escrow agreement,
Positron will deposit with the Escrow Agent and maintain at least half-yearly
during the term of this Agreement the most current version of the Design Source
Materials. Positron will pay any fees of the third party escrow agent in
connection with such escrow account, and will be subject to the equitable
remedy of specific performance should Positron fail to deposit and maintain
such most current version of the Design Source Materials with the Escrow Agent.
          
          10.2 RELEASE CONDITIONS.  Release of the Design Source Materials
to Premisys shall be made upon the occurrence of any of the following
conditions (the "RELEASE CONDITIONS") during the term of this Agreement: (i)
Positron becomes insolvent or admits insolvency or admits a general inability
to pay its debts as they become due, or files a petition for bankruptcy under
applicable law; (ii) an involuntary petition in bankruptcy is filed under
applicable law against Positron and is not  dismissed within sixty (60) days
thereafter; (iii) Positron merges with, is acquired by, or sells substantially
all of the assets of its business related to any of the Licensed Technology, to
any third party that, as determined by an independent third party reasonably
agreeable to the parties, provides support to Premisys set forth in Section 7
of this Agreement that is of a lower quality or slower response time than the
higher of: (A) the quality or response time provided by Positron prior to such
merger, acquisition or sale; or (B) the quality and response time that is
standard in the industry; or (iv) Positron ceases active operation of its
business, materially breaches this Agreement. As an additional RELEASE
CONDITION, release to Premisys of the Design Source Materials for any of the
ASICs, FPGAs, or Software will be made if Positron discontinues the support of
such ASIC, FPGA, or Software.
          
          10.3 ESCROW LICENSE.  Positron hereby grants to Premisys a
limited license to duplicate, use, modify and compile the Design Source
Materials, Specifications Design Documentation, Backplane Development Materials
and Licensed Manufacturing Materials for the purpose of modifying, upgrading,
supporting and maintaining the Licensed Technology. Premisys will not  exercise
its rights under such license unless and until a Release Conditions occurs.

     11.  WARRANTY.
          
          11.1 POWER AND AUTHORITY. Positron warrants to Premisys that it
has sufficient right and authority to grant to Premisys all licenses and rights
that Positron grants under this Agreement to allow Premisys to manufacture,
have manufactured, develop and distribute the Premisys Products and Software
anywhere in the world.
          
          11.2 SUFFICIENCY OF MANUFACTURING MATERIALS AND BACKPLANE DEVELOPMENT
MATERIALS.  Positron warrants that the ASIC Manufacturing Materials are
sufficient to allow the


                                      11
<PAGE>

ASIC Fabricator to manufacture and test each of the ASICs without
undue burden or delay in any reasonable quantity. Positron warrants that the
FPGA Manufacturing Materials are sufficient to allow a reasonable manufacturer
to manufacture and test the FPGAs by inserting the blank FPGAs set forth in
EXHIBIT E and the FPGA Manufacturing Materials into the FPGA Manufacturing
Environment set forth in EXHIBIT E attached hereto. Positron warrants that the
Backplane Development Materials are sufficient to allow any reasonably skilled
design engineer to modify the Backplane and create Modified Backplane
Manufacturing Materials without undue burden or delay so that circuit board
fabricators can manufacture the Modified Backplanes.
          
          11.3 SUFFICIENCY OF SPECIFICATIONS AND DESIGN DOCUMENTATION.
Positron warrants that the Specifications and Design Documentation are
sufficient to allow any reasonably skilled design engineer to incorporate the
Licensed Technology into any SONET/SDH product.
          
          11.4 SUFFICIENCY OF DESIGN SOURCE MATERIALS.  Positron warrants
the Design Source Materials placed in Escrow are sufficient to allow a
reasonably skilled design engineer to modify the ASICs and FPGAs and to produce
new versions of the Licensed Manufacturing Materials and Modified Backplane
Manufacturing Materials for such new versions of the Licensed Manufacturing
Materials.
          
          11.5 LIMITED WARRANTY.  Positron warrants to Premisys that
during the twelve (12) months following delivery to Premisys:
               
               (a)  ASICs built according to the ASIC Manufacturing Inputs,
FPGAs built according to the FPGA Manufacturing Inputs on the FPGA
Manufacturing Environment set forth in EXHIBIT E attached hereto, Backplanes,
if manufactured according to the Backplane Development Materials and the
corresponding Software will perform in accordance with the Specifications and
related documentation in all material respects; and
               
               (b)  the storage media containing the Software and FPGA
Manufacturing Materials will be free from defects in materials and workmanship.
In the event the Licensed Manufacturing Materials, Backplane Development
Materials, Software or storage media fail to conform to such warranty, in
addition to the remedies available to Premisys at law, Positron will, without
charge to Premisys, repair or replace such Licensed Manufacturing Materials,
Backplane Development Materials, Software or storage media.
          
          11.6 DISCLAIMER OF OTHER WARRANTIES. THE WARRANTIES AND REMEDIES
FOR BREACH OF SUCH WARRANTIES SET FORTH IN THIS SECTION ARE IN LIEU OF ALL
OTHER WARRANTIES AND REMEDIES FOR BREACH OF SUCH WARRANTIES, EXPRESS AND
IMPLIED, INCLUDING BUT NOT  LIMITED TO ANY IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
     

                                      12
<PAGE>

     12.  INFRINGEMENT INDEMNITY.
          
          12.1 DUTY TO INDEMNIFY AND DEFEND.
               
               (a)  Positron will indemnify Premisys against, and will defend
or settle at Positron's own expense, any action or other proceeding brought
against Premisys attributable to the acts or omissions of Positron to the
extent that it is based on a claim that the manufacture, use or sale of the
ASICs, FPGAs or Backplane, the duplication, distribution or use of the
Software, Licensed Manufacturing Materials, Backplane Development Materials,
Specifications, Design Documentation or Design Source Materials, as licensed in
this Agreement infringes any trademark, copyright or patent or that the
Software, Licensed Technology, Licensed Manufacturing Materials, Backplane
Development Materials, Specifications Design Documentation or Design Source
Materials incorporate any misappropriated trade secrets.
               
               (b)  Positron will pay any and all costs, damages, and expenses
(including but not limited to reasonable attorneys' fees) awarded against
Premisys in any such action or proceeding attributable to any such claim.
               
               (c)  Positron will have no obligation under this Section as to
any action, proceeding, or claim unless: (i) Positron is notified of it
promptly; (ii) Positron has sole control of its defense and settlement; and
(iii) Premisys provides Positron with reasonable assistance in its defense and
settlement at no cost to Positron.
          
          12.2 INJUNCTIONS.  If Premisys' use, manufacture or
distribution of any software, Licensed Technology, Licensed Manufacturing
Materials, Backplane Development Materials, Design Documentation,
Specifications or Design Source Materials (collectively, the "ITEMS") under the
terms of this Agreement is, or in Positron's opinion is likely to be, enjoined
due to the type of infringement or misappropriation specified in Subsection
12.1 above, then Positron may, at its sole option and expense, either:
               
               (a)  procure for Premisys the right to continue using such Items
               under the terms of this Agreement; or
               
               (b)  replace or modify such Items so that they are noninfringing
               and substantially equivalent in function to the enjoined
               Products; or
               
               (c)  if options 12.2(a) and 12.2(b) above cannot be accomplished
               despite the reasonable efforts of Positron, then Positron may
               both:
                    
                    (1)  terminate Premisys rights and Positron's obligations
                    under this Agreement with respect to such Licensed
                    Technology; and
                    
                    (2)  refund to Premisys its actual damages but in no event
                    more than all initial license fees, and all royalties paid
                    by Premisys to Positron for such Licensed Technology.
          

                                      13
<PAGE>

          12.3 EXCLUSIONS.  Positron will have no obligations under this
Section 12.2 with respect to infringement or misappropriation solely arising
from (i) modifications to the Licensed Technology that were not authorized by
Positron; or (ii) the use of the Licensed Technology in combination with
products not provided by Positron.
          
          12.4 PREMISYS DUTY TO DEFEND.  Premisys agrees that, to the
fullest extent permitted by law, it will indemnify, defend and hold Positron
harmless from and against any and all third-party claims, demands, costs,
expenses, suits and judgments incurred by Positron and solely attributable to
the acts or omissions of Premisys in its performance or failure to perform its
obligations under this Agreement.
     
     13.  LIMITATIONS OF LIABILITY.  IN NO EVENT WILL EITHER PARTY BE LIABLE TO
THE OTHER PARTY FOR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER
BASED ON BREACH OF CONTRACT, TORT (INCLUDING NEGLIGENCE), PRODUCT LIABILITY, OR
OTHERWISE, AND WHETHER OR NOT SUCH PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE UNLESS SUCH DAMAGE IS ATTRIBUTABLE TO THE WILLFUL MISCONDUCT OF A
PARTY.
     
     14.  GOVERNMENT APPROVALS, TERM AND TERMINATION.
          
          14.1 GOVERNMENT APPROVALS.  Following the Signature Date,
Positron will use its best efforts to obtain all required governmental
approvals set forth in EXHIBIT F, and Positron warrants that no other
government approvals are necessary. Until such approvals are obtained,
delivered in writing to Premisys and reasonably acceptable to Premisys as
stated by Premisys in a written letter of acceptance: (i) Premisys will have no
obligations under this Agreement and may terminate this Agreement for any
reason or for no reason; and (ii) Positron will have no obligations under this
Agreement except as set forth in this Section 14.1. Positron will indemnify
Premisys against, and will defend or settle at Positron's own expense, any
action or other proceeding brought against Premisys to the extent that it is
based on a claim any government approval necessary for the development,
manufacture or sale of the Premisys Products hereunder is or was not properly
obtained.
          
          14.2 TERM.  Except as otherwise provided in Section 14.1 of this
Agreement, the term of this Agreement will begin on the Effective Date and will
continue unless it is terminated in accordance with the provisions hereof.
          
          14.3 EVENTS OF TERMINATION.  Either party will have the right to
terminate this Agreement within sixty (60) days of any of the following events:
               
               (a)  the other party breaches any material term or condition or
this Agreement and fails to cure such breach within thirty (30) days after
written notice;
               

                                      14
<PAGE>

               (b)  the other party becomes the subject of a voluntary petition
in bankruptcy or any voluntary proceeding relating to insolvency, receivership,
liquidation, or composition for the benefit of creditors;
               
               (c)  the other party becomes the subject of an involuntary
petition in bankruptcy or any involuntary proceeding relating to insolvency,
receivership, liquidation, or composition for the benefit of creditors, if such
petition or proceeding is not dismissed within sixty (60) days of filing; or
               
               (d)  Premisys is unable to have manufactured by an ASIC
Fabricator one or more of the ASICs on reasonable terms consistent with
customary ASIC supply agreements.
          
          14.4 EFFECT OF TERMINATION.
               
               (a)  Upon termination or expiration of this Agreement, each
party, upon the written request of the other party, will (except as specified
in subsection (b) below) destroy all copies of the Confidential Information in
its possession or control, and an officer of such party will certify to the
other party in writing that it has done so.
               
               (b)  Upon termination or expiration of this Agreement, Positron
will, without charge to Premisys, permit Premisys to continue to provide
maintenance and support for the Products to its End Users and/or
Subdistributors upon the terms and conditions of Section 7.1 and continue to
use copies of the Licensed Manufacturing Materials, Backplane Design Materials,
Design Documentation, Specifications and Software, but only to the extent
needed to provide such services.
          
          14.5 EXCLUSIVE REMEDIES.  The equitable remedies of both parties
set forth herein and, subject to the provisions of Section 13, the remedies of
the parties at law are the exclusive remedies of the parties with respect to
this Agreement.
          
          14.6 SURVIVAL.  The rights and obligations of the parties
contained in Sections 2 (Licenses and Pricing), 8 (Confidentiality), 9
(Proprietary Rights), 10 (Escrow), 12 (Indemnities), 13 (Limitations of
Liability), and 14.4(b) (Effect of Termination) will survive the termination or
expiration of this Agreement.
     
     15.  COMPLIANCE WITH LAW.  Each party agrees to comply with all applicable
laws, rules, and regulations in connection with its activities under this
Agreement.
     
     16.  GENERAL
          
          16.1 ASSIGNMENT. This Agreement will bind and inure to the
benefit of each party's permitted successors and assigns. Neither party may
assign this Agreement, in whole or in part, without written consent of the
other party, such consent not to be unreasonably withheld.  Any attempt to
assign this Agreement with out such consent will be null and void.
          

                                      15
<PAGE>

          16.2 GOVERNING LAW. This Agreement will be governed by and
construed in accordance with the laws of the State of New York applicable to
agreements entered into, and to be performed entirely, within New York between
New York residents.
          
          16.3 SEVERABILITY.  If any provision of this Agreement is found
invalid or unenforceable, that provision will be enforced to the maximum extent
permissible, and the other provisions of this Agreement will remain in force.
          
          16.4 NOTICES.  All notices under this Agreement will be deemed
given when signed by a corporate officer of the sending party and delivered
personally, sent by confirmed facsimile transmission, or sent by certified or
registered mail or express courier, return receipt requested, to the address
shown above or as may otherwise be specified by either party to the other in
accordance with this section.
          
          16.5 INDEPENDENT CONTRACTORS.  The parties to this Agreement are
independent contractors. There is no relationship of partnership, joint
venture, employment, franchise, or agency between the parties. Neither party
will have the power to bind the other or incur obligations on the other's
behalf without the other's prior written consent.
          
          16.6 WAIVER.  No failure of either party to exercise or enforce
any of its rights under this Agreement will act as a waiver of such rights.
          
          16.7 ENTIRE AGREEMENT.  This Agreement and its exhibits are the
complete and exclusive agreement between the parties with respect to the
subject matter hereof, superseding and replacing any and all prior agreements,
communications, and understandings (both written and oral) regarding such
subject matter. This Agreement may only be modified, or any rights under it
waived, by a written document executed by both parties.
          
          16.8 LANGUAGE.  The parties have requested that this Agreement
be drafted in English.  Les parties aux presentes ont exige que ce Contrat soit
redige en langue anglaise.

The parties have caused this Agreement to be executed by their duly-authorized
representatives as of the Signature Date.

Premisys Communications, Inc.    Positron Fiber Systems Corp.

By:   /s/ Raymond C. Lin         By:   /s/ D. R. Gibbs
    ---------------------------     ------------------------------------

Name: Raymond C. Lin             Name: D. R. Gibbs
     --------------------------       ----------------------------------

Title: President/CEO             Title: President and CEO
      -------------------------        ---------------------------------


                               List of Exhibits

     Exhibit A:     ASICs, FPGAs, Backplanes, and Software


                                      16

<PAGE>

     Exhibit B:     Schedule of Deliveries
     Exhibit C:     Payments
     Exhibit D:     Escrow Materials and Development Environments
     Exhibit E:     FPGA Manufacturing Requirements
     Exhibit F:     Required Approvals from The Government of Quebec to
                    Manufacture and Distribute ASICs, FPGAs, Backplanes 
                    and Software Worldwide
     Exhibit G:     Standards


                                      17
<PAGE>

                                   EXHIBIT A
                    ASICs, FPGAs, Backplanes, and Software
                    --------------------------------------

     A.1  ASICS, FPGAS AND BACKPLANES.
          A.1.1     155 Mb/s SONET/SDH Optical Access Unit Field Programmable
     Gate Array(s) and SONET Optical Access Unit Application Specific
     Integrated Circuit (rated at 155 Mb/s).
          A.1.2     DS1 to VT 1.5 Mapper Application Specific Integrated
     Circuit(s).
          A.1.3     DS3 Mapper Field Programmable Gate Array(s).
          A.1.4     E 1 to TU12 Mapper Field Programmable Gate Array(s).
          A.1.5     RAM-based FPGA Ethernet Mapper for SONET and SDH.
          A.1.6     E3 Mapper Field Programmable Gate Array(s).
          A.1.7     System Backplane.
     A.2  SOFTWARE.
     Software drivers for existing ASICs and FPGAs are contained in the OSIRIS
rev. 3.3 software source code. Additional source code drivers will be provided
for ASICs and FPGAs not supported by the rev. 3.3 software as defined in
exhibit B.


<PAGE>

                                   EXHIBIT B
                            Schedule of Deliveries
                            ----------------------

                    Deliverable                             Delivery Date
------------------------------------------------------------------------------
B.0    Software: OSIRIS rev. 3.3 software specs and            12/31/96
       documentation, source code; that includes
       ASIC and FPGA drivers for deliverables B1, B2, B3.
B.1    Specifications and FPGA Manufacturing Materials         12/31/96
       for, and Design Documentation containing, 155 Mb/s 
       SONET/SDH Optical Access Unit FPGAs.   
B.2    Specifications for, and Design Documentation            12/31/96
       containing, the DS1 to VT1.5 Mapper ASIC.               
B.3    Specifications and FPGA Manufacturing Materials for,    12/31/96
       and Design Documentation containing, the DS3 
       Mapper FPGAs.                
B.4    Specifications for, and Design Documentation            12/31/96
       containing, the Backplane.                    
B.5    Specifications, software driver and FPGA Manufacturing   2/28/97
       Materials for, and Design Documentation containing, 
       the E1 to TU12 Mapper FPGA.     
B.6    Specifications and software driver for, and Design       3/31/97
       Documentation containing, the 155 Mb/s SONET Optical 
       Access Unit ASIC.      
B.7    No Deliverable.
B.8    Specifications, software driver and FPGA Manufacturing   3/31/97
       Materials for, and Design Documentation containing, 
       the RAM-based FPGA for Ethernet Mapper for SONET and
       SDH.  
B.9    Specifications, software driver and FPGA Manufacturing  10/31/97
       Materials for, and Design Documentation containing, 
       the E3 Mapper FPGA.   


<PAGE>

B.10   Specifications and software driver for, and Design      10/31/97
       Documentation containing, the E1 to TU12 Mapper ASIC.  


<PAGE>

                                   EXHIBIT C
                                   Payments
                                   --------

C.1  INITIAL PAYMENTS.
     Premisys will pay the following fees totaling up to $4,000,000 to Positron
upon the timely occurrence of each triggering event:
Fee          Triggering Event
---          ---------------
$500,000.00  Effective Date.
$500,000.00  Receipt by Premisys of the deliverables on the corresponding 
             schedule date set forth in Sections B.1, B.2, B.3 and B.4 
             of EXHIBIT B, and acceptance by Premisys.
$500,000.00  Receipt by Premisys of the deliverables on the corresponding 
             schedule date set forth in Section B.5 of EXHIBIT B, and 
             acceptance by Premisys.
$500,000.00  Receipt by Premisys of the deliverables on the corresponding 
             schedule date set forth in Sections B.6 and B.8 of EXHIBIT B, 
             and acceptance by Premisys. 
$500,000.00  Receipt by Premisys of the deliverables on the corresponding 
             schedule date set forth in Sections B.9 and B.10 of EXHIBIT B,
             and acceptance by Premisys. 
$500,000.00  April 30, 1998, only in the event that Positron has met its 
             obligations with respect to the deliverables and schedule set 
             forth in EXHIBIT B.
$500,000.00  April 30, 1999, only in the event that Positron has met its 
             obligations with respect to the deliverables and schedule 
             set forth in EXHIBIT B.
$500,000.00  April 30, 2000, only in the event that Positron has met its 
             obligations with respect to the deliverables and schedule set 
             forth in EXHIBIT B.
C.2. Royalties.  The royalties for each Licensed Product are equal to the base
royalty set forth in Section C.2.1, less one or both of the reductions set
forth in Section C.2.2. The royalties for a Licensed Product accrue upon the
date Premisys receives payment from its customers for the Premisys Products
containing such Licensed Product, subject to a credit for returns made by such
customers within sixty (60) days of the invoice date.


<PAGE>
                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


     C.2.1  BASE ROYALTIES.  Premisys will pay no separate royalty for the
Software. Premisys will pay Positron the following royalty for each ASIC, FPGA
or Backplane described in EXHIBIT A and any modified versions or any derivative
works of the ASICs, FPGAs, Backplane that is incorporated into any Premisys
Product, shipped to a customer and invoiced, for which payment is received by
Premisys:
ASICs, FPGAs and
Backplanes          Base Royalty
----------          ------------
A.1.1                 [
A.1.2
A.1.3
A.1.4
A.1.5
A.1.6
A.1.7                       **]
     C.2.2  REDUCTIONS.
          C.2.2.1  FOR THRESHOLD ROYALTIES ACCRUED. The base royalties set 
forth in Section C.2.1 will be reduced by the following percentages upon the 
accrual of the following accrued royalty amounts set forth in this Section 
C.2:
          
Reduction                       Accrued Royalties
---------                       -----------------
30%                             $1,500,000.00
60%                             $2,500,000.00
100%                            $4,000,000.00 (the "Maximum Royalty")
Nothing in this Agreement will be interpreted as requiring Premisys to pay any
royalty in excess of the Maximum Royalty, $4,000,000.00
          C.2.2.2  FOR FAILURE TO MAKE TIMELY DELIVERIES OF ANY DELIVERABLE.
In the event that a deliverable set forth in EXHIBIT B is not received
following ninety (90) days after the corresponding schedule date set forth in
EXHIBIT B during the period beginning ninety (90) days following the due date
for a deliverable set forth in EXHIBIT B and ending on the date such
deliverable is received by Premisys, the royalties set forth in Section C.2.1,
following the calculation of any applicable reduction set forth in Section
C.2.2.1, will be reduced by an additional fifty percent (50).


<PAGE>
                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 

                                   EXHIBIT D
                 Escrow Materials and Development Environments
                 ---------------------------------------------

D.1  ASIC ESCROW MATERIALS.
All materials and documentation in electronic format that are necessary or
useful for the modification, enhancement, relayout or transfer to a new
fabricator of each of the ASICs, including but not limited to:
     D.l.l  For DSI to VT1.5 Mapper ASIC (Fab; [                   **]
          a)   Schematics, symbols, wires, command files.
          b)   Related netlist ".CCL" file.
          c)   Related input test vectors ".SCL" file
          d)   Related expected output vectors ".CON" file
          e)   Related instruction file(s) for creation of ".CCL", ".SCL: and
".,CON" files listed above.
     D.1.2  For SONET OAU ASIC (Fab; [                   **])
          a)   Design netlist which consists of gate level Verilog files.
          b)   Production test patterns (also in Verilog).
          c)   Design source files (Verilog RTL-level models).
          d)   Simulation stimulus files in Verilog.
D.2  ASIC DEVELOPMENT ENVIRONMENT FOR ASIC ESCROW MATERIALS.
     D.2.1  For DSI to VT1.5 Mapper ASIC
          a)   Viewlogic Software to modify ASIC schematic design.
          b)   [                                             **] PDS software
on a Sun workstation for generation of input and expected output vectors, and
library and PDSCHECK.EXE in Viewlogic form.
     D.2.2  For SONET OAU ASIC
     The following are the used and recommended design tools used on a UNIX
workstation, however other compatible tools may also be used.
     a)   Verilog simulator; VCS from Viewlogic
     b)   Synthesis tool; Synopsys synthesis tool
     c)   Static timing analysis; Motive from Viewlogic
     d)   LSI Logic Library and WKS/Toolkit.

<PAGE>

D.3  FPGA ESCROW MATERIALS.
     All materials and documentation in electronic format that are necessary or
useful for the modification, enhancement, relayout or transfer to a new
production system of each of the FPGAs, including without limitation:
     D.3.1  Actel FPGAs
          a)   Files including but not limited to schematics, symbols, wires,
related ".CRT" files, related ".IPF" files in Viewlogic format.
     D.3.2  ORCA RAM Based FPGAs
          a)   Files including but not limited to schematic and VHDL files in
Viewlogic format.
D.4  FPGA DEVELOPMENT ENVIRONMENT FOR FPGA ESCROW MATERIALS.
     D.4.1  For Actel FPGAs
          a)   Schematic capture in ViewLogic (workview office version 7.2),
using Actel Library (Designer series 3.1).
          b)   VSM netlist generation using Actel library (Designer series 3.1)
for simulation in Viewlogic environment (workview office version 7.2)
          c)   Simulation of design using ViewSim from Viewlogic (workview
office version 7.2).
          d)   Verification of signal timing using ViewTrace from Viewlogic
(workview office version 7.2).
          e)   Conversion of Viewlogic netlist to Actel netlist
(Vl2ad/EDIFNETO: Workview office version 7.2).
          f)   Compiled netlist using Actel Designer series 3.1.
          g)   Placement for routing using Actel Designer series 3.1.
          h)   Routing of FPGA using Actel Designer Series 3.1.
          i)   Creation of back annotated netlist using Actel Designer series
3.1 (del2vl).
          j)   Verification of back annotated signal timing using ViewSim.
          k)   Fuse file for FPGA programmation (Actel Designer series 3.1).
          l)   Program for FPGA using APS2 from Actel Designer series 3.1, and
programming device "Activator 2S"
     D.4.2  For ORCA RAM Based FPGAs:
          a)   Schematic capture in Viewlogic (workview office version 7.2),
using ORCA library (ORCA Foundry Development tool version 9.0)
          b)   VSM netlist generation using ORCA library (ORCA Foundry
Development tool version 9.0) for simulation in viewlogic environment (workview
office version 7.2).
          c)   Simulation of design using ViewSim from Viewlogic (workview
office version 7.2).
          d)   Verification of signal timing using ViewTrace from Viewlogic

<PAGE>

          e)   Prerouted file .ncd database created by inputting design as WIR
(Viewlogic) into map shell (ORCA).
          f)   Place and route (ORCA Foundry Development tool version 9.0)
          g)   Black annotated netlist created using ORCA Foundry Development
tool version 9.0.
          h)   Verification of back annotated signal timing using ViewSim.
          i)   Bit string file library (created using ORCA Foundry Development
tool version 9.0).
          j)   Download cable to program FPGA for debugging purposes at this
stage.
          k)   PROM Created from bit stream.


<PAGE>

                                   EXHIBIT E
                        FPGA Manufacturing Requirements
                        -------------------------------

E.1  MANUFACTURING ENVIRONMENT.
ACTEL Designer Series (Latest P.C. Version)
Pentium 100 (or faster) IBM-compatible personal computer with serial port and
cable ACTEL ACTIVATOR Model 2S
E.2  BLANK FPGAS.
Model 100 or 160 PQFP ACTEL FPGAs


<PAGE>

                                   EXHIBIT F
Required Approvals from The Governments of Canada and Quebec to Manufacture and
-------------------------------------------------------------------------------
          distribute ASICs, FPGAs, Backplanes and Software Worldwide
          ----------------------------------------------------------
     (a)  Industry Canada
     (b)  Federal Office of Regional Development for Quebec
     (c)  Innovatech Du Grand Montreal
     (d)  Fond De Development Technologique Du Quebec (MICST)

<PAGE>
                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


                                   EXHIBIT G
                                   Standards
                                   ---------
G.1.  All ETSI SDH frame structure and multiplexing formats as defined in the
SDH standards documents for multiplexing E1 and E3 signals into an STM-1
signal.
G.2   Bellcore GR-1400-CORE
Comply         means all Licensed Technology as delivered to Premisys complies
               with the applicable Bellcore requirement
N/A            Not Applicable, i.e. the application is not supported within the
               product scope of the OSIRIS multiplexer, or the feature is not
               fully implemented, or not working against the latest version of
               the spec.
Future         will be implemented in a future version, or the implementation
               has started, but is not completed
Not Compliant  does not meet the requirement



I.   GR-1400-CORE COMPLIANCE STATEMENT
The compliance statement detailed below applies to GR-1400-CORE, Issue 1 March
1994, rev 1 Oct 1995.
------------------------------------------------------------------------------
 REQ. 
NUMBER       COMPLIANCE                      NOTE
------------------------------------------------------------------------------
------------------------------------------------------------------------------
R5-1          [
------------------------------------------------------------------------------
R5-2
------------------------------------------------------------------------------
R5-3
------------------------------------------------------------------------------
CR5-4
------------------------------------------------------------------------------
R5-4.1
------------------------------------------------------------------------------
R5-5
------------------------------------------------------------------------------
CR5-6                        Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-6.1                       Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-6.2
------------------------------------------------------------------------------
CR5-7                        Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-7.1
------------------------------------------------------------------------------
CR5.8               **]      Will be supported with future STS1 interface
------------------------------------------------------------------------------



                                   1 of 26
<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
R5-8.1        [              Will be supported with future STS1 interface
------------------------------------------------------------------------------
CR5-9
------------------------------------------------------------------------------
R5-9.1
------------------------------------------------------------------------------
O5-9.2
------------------------------------------------------------------------------
R5-9.3
------------------------------------------------------------------------------
R5-9.4
------------------------------------------------------------------------------
CR5-9.5
------------------------------------------------------------------------------
R5-9.6
------------------------------------------------------------------------------
R5-10
------------------------------------------------------------------------------
R5-11
------------------------------------------------------------------------------
O5-12                        OSIRIS will support OC-12 upgrading
------------------------------------------------------------------------------
R5-12.1
------------------------------------------------------------------------------
R5-12.2
------------------------------------------------------------------------------
O5-13
------------------------------------------------------------------------------
R5-13.1
------------------------------------------------------------------------------
R5-13.2
------------------------------------------------------------------------------
O5-14                        Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-14.1                      Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-14.2                      Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-15
------------------------------------------------------------------------------
R5-16
------------------------------------------------------------------------------
R5-17
------------------------------------------------------------------------------
R5-17.1
------------------------------------------------------------------------------
R5-17.2
------------------------------------------------------------------------------
CR5-17.3                     Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-17.3.1                    Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-17.3.2                    Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5.17.3.3                    Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-17.4                      [
------------------------------------------------------------------------------
R5-17.5
------------------------------------------------------------------------------
R5-17.6
------------------------------------------------------------------------------
R5-17.7
------------------------------------------------------------------------------
R5-17.8                                        **]
------------------------------------------------------------------------------
R5-17.9
------------------------------------------------------------------------------
O5-18
------------------------------------------------------------------------------
O5-19
------------------------------------------------------------------------------
R5-20
------------------------------------------------------------------------------
R5-21
------------------------------------------------------------------------------
CR5-22
------------------------------------------------------------------------------
R5-22.1
------------------------------------------------------------------------------
R5-22.2
------------------------------------------------------------------------------
R5-23
------------------------------------------------------------------------------
R5-24               **]
------------------------------------------------------------------------------


_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report

Issue 1.0, October 24, 1996            2 of 26

<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
O5-25         [
------------------------------------------------------------------------------
O5-26
------------------------------------------------------------------------------
R5-27.1                      Will be supported with future STS1 interface
------------------------------------------------------------------------------
O5-27.2                      Will be supported with future STS1 interface
------------------------------------------------------------------------------
CR5-27.3                     Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-28.1
------------------------------------------------------------------------------
O5-28.2
------------------------------------------------------------------------------
CR5-28.3                     Will be supported with future STS1 interface
------------------------------------------------------------------------------
R5-29
------------------------------------------------------------------------------
R5-30
------------------------------------------------------------------------------
R5-31
------------------------------------------------------------------------------
R5-32
------------------------------------------------------------------------------
R5-33
------------------------------------------------------------------------------
R6-1
------------------------------------------------------------------------------
R6-2
------------------------------------------------------------------------------
R6-2.1
------------------------------------------------------------------------------
R6-2.2
------------------------------------------------------------------------------
R6-3
------------------------------------------------------------------------------
R6-4
------------------------------------------------------------------------------
R6-5
------------------------------------------------------------------------------
R6-6
------------------------------------------------------------------------------
R6-7                         Higher Priority Alarm is issued (LOP,....)
------------------------------------------------------------------------------
O6-8
------------------------------------------------------------------------------
R6-9
------------------------------------------------------------------------------
R6-10                        Refer to GR-253-CORE compliance report
------------------------------------------------------------------------------
R6-11
------------------------------------------------------------------------------
R6-12
------------------------------------------------------------------------------
R6-13
------------------------------------------------------------------------------
R6-14
------------------------------------------------------------------------------
R6-15
------------------------------------------------------------------------------
R6-16
------------------------------------------------------------------------------
R6-17
------------------------------------------------------------------------------
R6-18
------------------------------------------------------------------------------
R6-19
------------------------------------------------------------------------------
R6-20
------------------------------------------------------------------------------
R6-20.1
------------------------------------------------------------------------------
R6-20.2
------------------------------------------------------------------------------
R6-20.3
------------------------------------------------------------------------------
R6-20.4
------------------------------------------------------------------------------
R6-20.5
------------------------------------------------------------------------------
R6-20.6
------------------------------------------------------------------------------
R6-21                        Individual paths only
------------------------------------------------------------------------------
R6-22                **]
------------------------------------------------------------------------------



_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            3 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
R6-23     [
------------------------------------------------------------------------------
R6-24
------------------------------------------------------------------------------
CR6-25
------------------------------------------------------------------------------
R6-26
------------------------------------------------------------------------------
O6-27
------------------------------------------------------------------------------
R6-28
------------------------------------------------------------------------------
O6-29
------------------------------------------------------------------------------
R6-30
------------------------------------------------------------------------------
R6-31
------------------------------------------------------------------------------
R6-32
------------------------------------------------------------------------------
R6-33
------------------------------------------------------------------------------
O6-34
------------------------------------------------------------------------------
R6-34.1
------------------------------------------------------------------------------
R6-34.2
------------------------------------------------------------------------------
R6-34.3
------------------------------------------------------------------------------
R6-34.4               **]
------------------------------------------------------------------------------



G.3. BellCore SONET GR253-CORE Issue 2, December 1995

Comply

N/A

Future

Not Compliant



_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            4 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 



COMPLIANT ITEMS ANALYSIS
------------------------------------------------------------------------------
GR CODE TYPE         REQ. NUMBER          PERMANENT            STATUS
                                          NUMBER         
------------------------------------------------------------------------------
(CR)                     2-1              1                    [
------------------------------------------------------------------------------
(CR)                     2-2              2
------------------------------------------------------------------------------
(CR)                     2-3              3
------------------------------------------------------------------------------
(R)                      3-1              4
------------------------------------------------------------------------------
(O)                      3-2              5
------------------------------------------------------------------------------
(R)                      3-3              6
------------------------------------------------------------------------------
(R)                      3-4              7
------------------------------------------------------------------------------
(R)                      3-5              8
------------------------------------------------------------------------------
(R)                      3-6              9
------------------------------------------------------------------------------
(R)                      3-7             10
------------------------------------------------------------------------------
(R)                      3-8             11
------------------------------------------------------------------------------
(R)                      3-9             12
------------------------------------------------------------------------------
(R)                     3-10             13
------------------------------------------------------------------------------
(R)                     3-11             14
------------------------------------------------------------------------------
(R)                     3-12             15
------------------------------------------------------------------------------
(R)                     3-13             16
------------------------------------------------------------------------------
(O)                     3-14             17
------------------------------------------------------------------------------
(R)                     3-15             18
------------------------------------------------------------------------------
(R)                     3-16             19
------------------------------------------------------------------------------
(R)                     3-17             20
------------------------------------------------------------------------------
(R)                     3-18             21
------------------------------------------------------------------------------
(R)                     3-19             22
------------------------------------------------------------------------------
(R)                     3-20             23
------------------------------------------------------------------------------
(R)                     3-21             24
------------------------------------------------------------------------------
(R)                     3-22             25
------------------------------------------------------------------------------
(R)                     3-23             26
------------------------------------------------------------------------------
(R)                     3-24             27
------------------------------------------------------------------------------
(R)                     3-25             28
------------------------------------------------------------------------------
(R)                     3-26             29
------------------------------------------------------------------------------
(R)                     3-27           30v2
------------------------------------------------------------------------------
(R)                     3-28             31
------------------------------------------------------------------------------
(R)                     3-29             32
------------------------------------------------------------------------------
(R)                     3-30             33
------------------------------------------------------------------------------
(R)                     3-31             34
------------------------------------------------------------------------------
(R)                     3-32             35
------------------------------------------------------------------------------
(R)                     3-33             36
------------------------------------------------------------------------------
(O)                     3-34             37
------------------------------------------------------------------------------
(CR)                    3-35             38
------------------------------------------------------------------------------
(R)                     3-36             39                             **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            5 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(CR)                    3-37             40                    [
------------------------------------------------------------------------------
(CR)                    3-38             41
------------------------------------------------------------------------------
(R)                     3-39             42
------------------------------------------------------------------------------
(R)                     3-40             43
------------------------------------------------------------------------------
(CR)                    3-41             44
------------------------------------------------------------------------------
(CR)                    3-42             45
------------------------------------------------------------------------------
(R)                     3-43             46
------------------------------------------------------------------------------
(R)                     3-44             47
------------------------------------------------------------------------------
(CR)                    3-45             48
------------------------------------------------------------------------------
(CR)                    3-46             49
------------------------------------------------------------------------------
(CR)                    3-47             50
------------------------------------------------------------------------------
(R)                     3-48             51
------------------------------------------------------------------------------
(R)                     3-49             52
------------------------------------------------------------------------------
(R)                     3-50             53
------------------------------------------------------------------------------
(R)                     3-51             54
------------------------------------------------------------------------------
(R)                     3-52             55
------------------------------------------------------------------------------
(R)                     3-53             56
------------------------------------------------------------------------------
(R)                     3-55             57
------------------------------------------------------------------------------
(R)                     3-56             58
------------------------------------------------------------------------------
(R)                     3-57             59
------------------------------------------------------------------------------
(R)                     3-58             60
------------------------------------------------------------------------------
(R)                     3-59             61
------------------------------------------------------------------------------
(R)                     3-60             62
------------------------------------------------------------------------------
(R)                     3-62             63
------------------------------------------------------------------------------
(R)                     3-63             64
------------------------------------------------------------------------------
(R)                     3-64             65
------------------------------------------------------------------------------
(R)                     3-65             66
------------------------------------------------------------------------------
(R)                     3-66             67
------------------------------------------------------------------------------
(R)                     3-67             68
------------------------------------------------------------------------------
(R)                     3-69             69
------------------------------------------------------------------------------
(R)                     3-70             70
------------------------------------------------------------------------------
(R)                     3-71             71
------------------------------------------------------------------------------
(R)                     3-74             72
------------------------------------------------------------------------------
(R)                     3-75             73
------------------------------------------------------------------------------
(R)                     3-76             74
------------------------------------------------------------------------------
(R)                     3-77             75
------------------------------------------------------------------------------
(R)                     3-78             76
------------------------------------------------------------------------------
(R)                     3-79             77
------------------------------------------------------------------------------
(R)                     3-80             78
------------------------------------------------------------------------------
(R)                     3-81             79
------------------------------------------------------------------------------
(R)                     3-82             80
------------------------------------------------------------------------------
(R)                     3-83             81
------------------------------------------------------------------------------
(R)                     3-84             82                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            6 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     3-85             83                    [
------------------------------------------------------------------------------
(R)                     3-86             84
------------------------------------------------------------------------------
(R)                     3-87             85
------------------------------------------------------------------------------
(R)                     3-88             86
------------------------------------------------------------------------------
(R)                     3-89             87
------------------------------------------------------------------------------
(R)                     3-90             88
------------------------------------------------------------------------------
(R)                     3-91             89
------------------------------------------------------------------------------
(O)                     3-92             90
------------------------------------------------------------------------------
(R)                     3-93             91
------------------------------------------------------------------------------
(R)                     3-94             92
------------------------------------------------------------------------------
(R)                     3-95             93
------------------------------------------------------------------------------
(R)                     3-96             94
------------------------------------------------------------------------------
(R)                     3-97             95
------------------------------------------------------------------------------
(R)                     3-98           96v2
------------------------------------------------------------------------------
(O)                    3-100             97
------------------------------------------------------------------------------
(R)                    3-101             98
------------------------------------------------------------------------------
(R)                    3-102             99
------------------------------------------------------------------------------
(R)                    3-103            100
------------------------------------------------------------------------------
(R)                    3-104            101
------------------------------------------------------------------------------
(R)                    3-105            102
------------------------------------------------------------------------------
(O)                    3-106            103
------------------------------------------------------------------------------
(R)                    3-107            104
------------------------------------------------------------------------------
(R)                    3-108            105
------------------------------------------------------------------------------
(R)                    3-109            106
------------------------------------------------------------------------------
(R)                    3-110            107
------------------------------------------------------------------------------
(R)                    3-111          108v2
------------------------------------------------------------------------------
(R)                    3-113            109
------------------------------------------------------------------------------
(R)                      4-1            110
------------------------------------------------------------------------------
(R)                      4-2            111
------------------------------------------------------------------------------
(R)                      4-3            112
------------------------------------------------------------------------------
(R)                      4-4            113
------------------------------------------------------------------------------
(O)                      4-5            114
------------------------------------------------------------------------------
(R)                      4-6            115
------------------------------------------------------------------------------
(R)                      4-7            116
------------------------------------------------------------------------------
(R)                      4-8            117
------------------------------------------------------------------------------
(O)                      4-9            118
------------------------------------------------------------------------------
(R)                     4-10            119
------------------------------------------------------------------------------
(R)                     4-11            120
------------------------------------------------------------------------------
(R)                     4-12            121
------------------------------------------------------------------------------
(O)                     4-13            122
------------------------------------------------------------------------------
(R)                     4-14            123
------------------------------------------------------------------------------
(CR)                    4-15            124
------------------------------------------------------------------------------
(R)                     4-16            125                           **] 
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            7 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     4-17            126                    [
------------------------------------------------------------------------------
(R)                     4-18            127
------------------------------------------------------------------------------
(CR)                    4-19          128v2
------------------------------------------------------------------------------
(R)                     4-21            129
------------------------------------------------------------------------------
(R)                     4-22            130
------------------------------------------------------------------------------
(R)                      5-1            131
------------------------------------------------------------------------------
(R)                      5-2            132
------------------------------------------------------------------------------
(R)                      5-3            133
------------------------------------------------------------------------------
(R)                      5-6            134
------------------------------------------------------------------------------
(R)                      5-7            135
------------------------------------------------------------------------------
(CR)                     5-8            136
------------------------------------------------------------------------------
(O)                      5-9            137
------------------------------------------------------------------------------
(O)                     5-10            138
------------------------------------------------------------------------------
(R)                     5-11            139
------------------------------------------------------------------------------
(R)                     5-12            140
------------------------------------------------------------------------------
(R)                     5-13            141
------------------------------------------------------------------------------
(R)                     5-14            142
------------------------------------------------------------------------------
(CR)                    5-15            143
------------------------------------------------------------------------------
(CR)                    5-16            144
------------------------------------------------------------------------------
(CR)                    5-17            145
------------------------------------------------------------------------------
(R)                     5-18            146
------------------------------------------------------------------------------
(CR)                    5-19            147
------------------------------------------------------------------------------
(CR)                    5-20            148
------------------------------------------------------------------------------
(CR)                    5-21            149
------------------------------------------------------------------------------
(CR)                    5-22            150
------------------------------------------------------------------------------
(R)                     5-23            151
------------------------------------------------------------------------------
(R)                     5-24            152
------------------------------------------------------------------------------
(CR)                    5-25            153
------------------------------------------------------------------------------
(R)                     5-26            154
------------------------------------------------------------------------------
(CR)                    5-27            155
------------------------------------------------------------------------------
(CR)                    5-28            156
------------------------------------------------------------------------------
(CR)                    5-29            157
------------------------------------------------------------------------------
(R)                     5-30            158
------------------------------------------------------------------------------
(O)                     5-31            159
------------------------------------------------------------------------------
(R)                     5-32            160
------------------------------------------------------------------------------
(O)                     5-33            161
------------------------------------------------------------------------------
(R)                     5-34            162
------------------------------------------------------------------------------
(CR)                    5-35            163
------------------------------------------------------------------------------
(R)                     5-36            164
------------------------------------------------------------------------------
(R)                     5-37            165
------------------------------------------------------------------------------
(CR)                    5-38            166
------------------------------------------------------------------------------
(R)                     5-39            167
------------------------------------------------------------------------------
(O)                     5-40            168                            **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            8 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     5-41            169                    [
------------------------------------------------------------------------------
(O)                     5-42            170
------------------------------------------------------------------------------
(R)                     5-43            171
------------------------------------------------------------------------------
(O)                     5-44            172
------------------------------------------------------------------------------
(O)                     5-45            173
------------------------------------------------------------------------------
(R)                     5-46            174
------------------------------------------------------------------------------
(R)                     5-47            175
------------------------------------------------------------------------------
(R)                     5-49            176
------------------------------------------------------------------------------
(O)                     5-50          177v2
------------------------------------------------------------------------------
(R)                     5-54            178
------------------------------------------------------------------------------
(R)                     5-55            179
------------------------------------------------------------------------------
(R)                     5-56            180
------------------------------------------------------------------------------
(R)                     5-57            181
------------------------------------------------------------------------------
(R)                     5-58            182
------------------------------------------------------------------------------
(R)                     5-59            183
------------------------------------------------------------------------------
(R)                     5-60            184
------------------------------------------------------------------------------
(R)                     5-61            185
------------------------------------------------------------------------------
(R)                     5-62            186
------------------------------------------------------------------------------
(R)                     5-63            187
------------------------------------------------------------------------------
(R)                     5-64            188
------------------------------------------------------------------------------
(R)                     5-65            189
------------------------------------------------------------------------------
(R)                     5-66          190v2
------------------------------------------------------------------------------
(R)                     5-67            191
------------------------------------------------------------------------------
(R)                     5-68            192
------------------------------------------------------------------------------
(R)                     5-69            193
------------------------------------------------------------------------------
(R)                     5-70            194
------------------------------------------------------------------------------
(R)                     5-71            195
------------------------------------------------------------------------------
(R)                     5-72            196
------------------------------------------------------------------------------
(R)                     5-73            197
------------------------------------------------------------------------------
(R)                     5-74            198
------------------------------------------------------------------------------
(R)                     5-75            199
------------------------------------------------------------------------------
(R)                     5-76            200
------------------------------------------------------------------------------
(R)                     5-77            201
------------------------------------------------------------------------------
(R)                     5-78            202
------------------------------------------------------------------------------
(R)                     5-79            203
------------------------------------------------------------------------------
(R)                     5-80            204
------------------------------------------------------------------------------
(R)                     5-81            205
------------------------------------------------------------------------------
(R)                     5-82            206
------------------------------------------------------------------------------
(R)                     5-84            207
------------------------------------------------------------------------------
(O)                     5-85            208
------------------------------------------------------------------------------
(R)                     5-86            209
------------------------------------------------------------------------------
(R)                     5-87            210
------------------------------------------------------------------------------
(R)                     5-88            211                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            9 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     5-89            212                    [
------------------------------------------------------------------------------
(CR)                    5-90            213
------------------------------------------------------------------------------
(R)                     5-91            214
------------------------------------------------------------------------------
(R)                     5-92            215
------------------------------------------------------------------------------
(R)                     5-93            216
------------------------------------------------------------------------------
(R)                     5-94            217
------------------------------------------------------------------------------
(R)                     5-98            222
------------------------------------------------------------------------------
(R)                     5-99            223
------------------------------------------------------------------------------
(R)                     5-96            224
------------------------------------------------------------------------------
(R)                     5-97          225v2
------------------------------------------------------------------------------
(R)                    5-100            226
------------------------------------------------------------------------------
(R)                    5-101            227
------------------------------------------------------------------------------
(CR)                   5-104            239
------------------------------------------------------------------------------
(R)                    5-105            240
------------------------------------------------------------------------------
(R)                    5-106            241
------------------------------------------------------------------------------
(R)                    5-107            242
------------------------------------------------------------------------------
(CR)                   5-108            243
------------------------------------------------------------------------------
(CR)                   5-109            244
------------------------------------------------------------------------------
(CR)                   5-110            245
------------------------------------------------------------------------------
(R)                    5-111            246
------------------------------------------------------------------------------
(R)                    5-112            247
------------------------------------------------------------------------------
(R)                    5-114            248
------------------------------------------------------------------------------
(R)                    5-115            249
------------------------------------------------------------------------------
(R)                    5-122            250
------------------------------------------------------------------------------
(CR)                   5-116            251
------------------------------------------------------------------------------
(CR)                   5-117            252
------------------------------------------------------------------------------
(R)                    5-123            253
------------------------------------------------------------------------------
(R)                    5-124            254
------------------------------------------------------------------------------
(R)                    5-126            255
------------------------------------------------------------------------------
(R)                    5-127            256
------------------------------------------------------------------------------
(R)                    5-130            257
------------------------------------------------------------------------------
(R)                    5-131            258
------------------------------------------------------------------------------
(R)                    5-132          259v2
------------------------------------------------------------------------------
(O)                    5-133            260
------------------------------------------------------------------------------
(R)                    5-136            261
------------------------------------------------------------------------------
(O)                    5-137          262v2
------------------------------------------------------------------------------
(O)                    5-134          263v2
------------------------------------------------------------------------------
(R)                    5-129          264v2
------------------------------------------------------------------------------
(R)                    5-139            265
------------------------------------------------------------------------------
(CR)                   5-140            266                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            10 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    5-141          267v2                    [
------------------------------------------------------------------------------
(R)                    5-142            268
------------------------------------------------------------------------------
(R)                    5-144            271
------------------------------------------------------------------------------
(R)                    5-145            272
------------------------------------------------------------------------------
(R)                    5-146          273v2
------------------------------------------------------------------------------
(CR)                   5-147            274
------------------------------------------------------------------------------
(O)                    5-148            276
------------------------------------------------------------------------------
(CR)                   5-149            277
------------------------------------------------------------------------------
(R)                    5-150            278
------------------------------------------------------------------------------
(R)                    5-151            279
------------------------------------------------------------------------------
(R)                    5-152            280
------------------------------------------------------------------------------
(R)                    5-153            281
------------------------------------------------------------------------------
(R)                    5-154            282
------------------------------------------------------------------------------
(R)                    5-155            283
------------------------------------------------------------------------------
(R)                    5-156            284
------------------------------------------------------------------------------
(R)                    5-157          285v2
------------------------------------------------------------------------------
(R)                    5-158            286
------------------------------------------------------------------------------
(CR)                   5-159            287
------------------------------------------------------------------------------
(R)                    5-160            288
------------------------------------------------------------------------------
(R)                    5-161            289
------------------------------------------------------------------------------
(R)                    5-162          290v2
------------------------------------------------------------------------------
(R)                    5-163            291
------------------------------------------------------------------------------
(R)                    5-164            292
------------------------------------------------------------------------------
(R)                    5-165          293v2
------------------------------------------------------------------------------
(R)                    5-166            294
------------------------------------------------------------------------------
(CR)                   5-167            295
------------------------------------------------------------------------------
(R)                    5-168            296
------------------------------------------------------------------------------
(R)                    5-169            297
------------------------------------------------------------------------------
(R)                    5-170          298v2
------------------------------------------------------------------------------
(R)                    5-171          300v2
------------------------------------------------------------------------------
(R)                    5-172          302v2
------------------------------------------------------------------------------
(R)                    5-173            305
------------------------------------------------------------------------------
(R)                    5-174            310
------------------------------------------------------------------------------
(R)                    5-175            311
------------------------------------------------------------------------------
(R)                    5-176            312
------------------------------------------------------------------------------
(R)                    5-177            313
------------------------------------------------------------------------------
(R)                    5-178            314
------------------------------------------------------------------------------
(R)                    5-179          315v2
------------------------------------------------------------------------------
(R)                    5-180            316
------------------------------------------------------------------------------
(R)                    5-182          317v2                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            11 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    5-181            318                    [
------------------------------------------------------------------------------
(R)                    5-183            319
------------------------------------------------------------------------------
(O)                    5-184            320
------------------------------------------------------------------------------
(R)                    5-185            321
------------------------------------------------------------------------------
(R)                    5-186            322
------------------------------------------------------------------------------
(R)                    5-187            323
------------------------------------------------------------------------------
(R)                    5-188            324
------------------------------------------------------------------------------
(R)                    5-189            325
------------------------------------------------------------------------------
(R)                    5-190            326
------------------------------------------------------------------------------
(R)                    5-191            327
------------------------------------------------------------------------------
(R)                    5-192            328
------------------------------------------------------------------------------
(R)                    5-193            329
------------------------------------------------------------------------------
(R)                    5-194            330
------------------------------------------------------------------------------
(R)                    5-195            331
------------------------------------------------------------------------------
(R)                    5-196            332
------------------------------------------------------------------------------
(R)                    5-197            333
------------------------------------------------------------------------------
(R)                    5-198            334
------------------------------------------------------------------------------
(R)                    5-199            335
------------------------------------------------------------------------------
(R)                    5-200            336
------------------------------------------------------------------------------
(R)                    5-201            337
------------------------------------------------------------------------------
(R)                    5-202            338
------------------------------------------------------------------------------
(R)                    5-203            339
------------------------------------------------------------------------------
(R)                    5-204            340
------------------------------------------------------------------------------
(R)                    5-205            341
------------------------------------------------------------------------------
(R)                    5-206            342
------------------------------------------------------------------------------
(R)                    5-207          343v2
------------------------------------------------------------------------------
(R)                    5-209            345
------------------------------------------------------------------------------
(R)                    5-210            346
------------------------------------------------------------------------------
(R)                    5-211            347
------------------------------------------------------------------------------
(R)                    5-212            348
------------------------------------------------------------------------------
(O)                    5-213            349
------------------------------------------------------------------------------
(O)                    5-214            350
------------------------------------------------------------------------------
(R)                    5-215            351
------------------------------------------------------------------------------
(R)                    5-216            352
------------------------------------------------------------------------------
(R)                    5-217            353
------------------------------------------------------------------------------
(O)                    5-218            354
------------------------------------------------------------------------------
(R)                    5-219            355
------------------------------------------------------------------------------
(O)                    5-220            356
------------------------------------------------------------------------------
(R)                    5-221            357
------------------------------------------------------------------------------
(R)                    5-227            358
------------------------------------------------------------------------------
(R)                    5-228            359
------------------------------------------------------------------------------
(R)                    5-229          360v2
------------------------------------------------------------------------------
(R)                      6-2          361v2                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            12 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                      6-1            366                    [
------------------------------------------------------------------------------
(R)                      6-5            367
------------------------------------------------------------------------------
(R)                      6-6            368
------------------------------------------------------------------------------
(R)                      6-7            369
------------------------------------------------------------------------------
(R)                      6-8            370
------------------------------------------------------------------------------
(R)                      6-9            371
------------------------------------------------------------------------------
(O)                     6-10            372
------------------------------------------------------------------------------
(R)                     6-11            373
------------------------------------------------------------------------------
(R)                     6-12            374
------------------------------------------------------------------------------
(R)                     6-13            375
------------------------------------------------------------------------------
(R)                     6-14            376
------------------------------------------------------------------------------
(CR)                    6-15            377
------------------------------------------------------------------------------
(R)                     6-16            378
------------------------------------------------------------------------------
(R)                     6-17            379
------------------------------------------------------------------------------
(R)                     6-18            380
------------------------------------------------------------------------------
(R)                     6-19            381
------------------------------------------------------------------------------
(R)                     6-20            382
------------------------------------------------------------------------------
(R)                     6-21            383
------------------------------------------------------------------------------
(R)                     6-22            384
------------------------------------------------------------------------------
(R)                     6-23            385
------------------------------------------------------------------------------
(R)                     6-24            386
------------------------------------------------------------------------------
(R)                     6-25            387
------------------------------------------------------------------------------
(R)                     6-26            388
------------------------------------------------------------------------------
(R)                     6-27            389
------------------------------------------------------------------------------
(R)                     6-28            390
------------------------------------------------------------------------------
(R)                     6-29            391
------------------------------------------------------------------------------
(R)                     6-30            392
------------------------------------------------------------------------------
(R)                     6-31            393
------------------------------------------------------------------------------
(R)                     6-32            394
------------------------------------------------------------------------------
(R)                     6-33            395
------------------------------------------------------------------------------
(R)                     6-34            397
------------------------------------------------------------------------------
(R)                     6-35            398
------------------------------------------------------------------------------
(CR)                    6-36            399
------------------------------------------------------------------------------
(R)                     6-37            400
------------------------------------------------------------------------------
(R)                     6-38            402
------------------------------------------------------------------------------
(R)                     6-39            403
------------------------------------------------------------------------------
(R)                     6-40            404                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            13 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     6-41            405                    [
------------------------------------------------------------------------------
(R)                     6-42            406
------------------------------------------------------------------------------
(R)                     6-43            407
------------------------------------------------------------------------------
(R)                     6-44            408
------------------------------------------------------------------------------
(R)                     6-45            409
------------------------------------------------------------------------------
(R)                     6-46            410
------------------------------------------------------------------------------
(R)                     6-47            411
------------------------------------------------------------------------------
(O)                     6-48            412
------------------------------------------------------------------------------
(R)                     6-49            413
------------------------------------------------------------------------------
(O)                     6-50            414
------------------------------------------------------------------------------
(O)                     6-51            415
------------------------------------------------------------------------------
(R)                     6-52          416v2
------------------------------------------------------------------------------
(R)                     6-54            417
------------------------------------------------------------------------------
(R)                     6-55          418v2
------------------------------------------------------------------------------
(R)                     6-56            419
------------------------------------------------------------------------------
(R)                     6-57            420
------------------------------------------------------------------------------
(R)                     6-58            421
------------------------------------------------------------------------------
(R)                     6-59            422
------------------------------------------------------------------------------
(R)                     6-60            423
------------------------------------------------------------------------------
(R)                     6-61            424
------------------------------------------------------------------------------
(O)                     6-62            425
------------------------------------------------------------------------------
(R)                     6-63          426v2
------------------------------------------------------------------------------
(R)                     6-64            427
------------------------------------------------------------------------------
(R)                     6-65          428v2
------------------------------------------------------------------------------
(R)                     6-66            429
------------------------------------------------------------------------------
(R)                     6-70          430v2
------------------------------------------------------------------------------
(R)                     6-72          431v2
------------------------------------------------------------------------------
(R)                     6-73          432v2
------------------------------------------------------------------------------
(R)                     6-78          433v2
------------------------------------------------------------------------------
(R)                     6-80            434
------------------------------------------------------------------------------
(R)                     6-81          435v2
------------------------------------------------------------------------------
(R)                     6-83            436
------------------------------------------------------------------------------
(R)                     6-84            437
------------------------------------------------------------------------------
(R)                     6-85            438
------------------------------------------------------------------------------
(R)                     6-86            439
------------------------------------------------------------------------------
(R)                     6-87            440
------------------------------------------------------------------------------
(R)                     6-88            441
------------------------------------------------------------------------------
(CR)                    6-89            442
------------------------------------------------------------------------------
(O)                     6-90            443
------------------------------------------------------------------------------
(R)                     6-91            444
------------------------------------------------------------------------------
(R)                     6-92            445
------------------------------------------------------------------------------
(R)                     6-93            446
------------------------------------------------------------------------------
(R)                     6-94            447                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            14 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     6-95            448                    [
------------------------------------------------------------------------------
(R)                     6-96            449
------------------------------------------------------------------------------
(R)                     6-97            450
------------------------------------------------------------------------------
(R)                     6-98            451
------------------------------------------------------------------------------
(R)                     6-99            452
------------------------------------------------------------------------------
(O)                    6-100            453
------------------------------------------------------------------------------
(R)                    6-101            454
------------------------------------------------------------------------------
(R)                    6-102            455
------------------------------------------------------------------------------
(R)                    6-103            456
------------------------------------------------------------------------------
(R)                    6-104            457
------------------------------------------------------------------------------
(R)                    6-105            458
------------------------------------------------------------------------------
(R)                    6-106            459
------------------------------------------------------------------------------
(R)                    6-107            460
------------------------------------------------------------------------------
(R)                    6-108            461
------------------------------------------------------------------------------
(R)                    6-109            462
------------------------------------------------------------------------------
(R)                    6-110            463
------------------------------------------------------------------------------
(R)                    6-111            464
------------------------------------------------------------------------------
(R)                    6-112            465
------------------------------------------------------------------------------
(R)                    6-113            466
------------------------------------------------------------------------------
(R)                    6-114          467v2
------------------------------------------------------------------------------
(R)                    6-115            468
------------------------------------------------------------------------------
(R)                    6-116            469
------------------------------------------------------------------------------
(R)                    6-117            470
------------------------------------------------------------------------------
(R)                    6-118            471
------------------------------------------------------------------------------
(R)                    6-119            472
------------------------------------------------------------------------------
(O)                    6-120            473
------------------------------------------------------------------------------
(R)                    6-121            476
------------------------------------------------------------------------------
(O)                    6-122            477
------------------------------------------------------------------------------
(R)                    6-123          478v2
------------------------------------------------------------------------------
(R)                    6-124            479
------------------------------------------------------------------------------
(R)                    6-125          480v2
------------------------------------------------------------------------------
(R)                    6-126            481
------------------------------------------------------------------------------
(O)                    6-127            482
------------------------------------------------------------------------------
(R)                    6-128            485
------------------------------------------------------------------------------
(O)                    6-129            486
------------------------------------------------------------------------------
(R)                    6-130            488
------------------------------------------------------------------------------
(R)                    6-131          489v2
------------------------------------------------------------------------------
(O)                    6-132            491
------------------------------------------------------------------------------
(O)                    6-133            492
------------------------------------------------------------------------------
(R)                    6-134            495
------------------------------------------------------------------------------
(O)                    6-135            496
------------------------------------------------------------------------------
(R)                    6-136          497v2
------------------------------------------------------------------------------
(R)                    6-137            498                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            15 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    6-138            499                    [
------------------------------------------------------------------------------
(R)                    6-139            501
------------------------------------------------------------------------------
(O)                    6-140            502
------------------------------------------------------------------------------
(R)                    6-141            505
------------------------------------------------------------------------------
(O)                    6-142            506
------------------------------------------------------------------------------
(R)                    6-143            508
------------------------------------------------------------------------------
(R)                    6-144            509
------------------------------------------------------------------------------
(R)                    6-145          512v2
------------------------------------------------------------------------------
(R)                    6-146          513v2
------------------------------------------------------------------------------
(R)                    6-147            514
------------------------------------------------------------------------------
(R)                    6-148            515
------------------------------------------------------------------------------
(R)                    6-149            516
------------------------------------------------------------------------------
(R)                    6-150            517
------------------------------------------------------------------------------
(R)                    6-151            518
------------------------------------------------------------------------------
(R)                    6-152          519v2
------------------------------------------------------------------------------
(R)                    6-153          521v2
------------------------------------------------------------------------------
(R)                    6-154            523
------------------------------------------------------------------------------
(R)                    6-155            524
------------------------------------------------------------------------------
(R)                    6-156            525
------------------------------------------------------------------------------
(R)                    6-157            526
------------------------------------------------------------------------------
(R)                    6-158            527
------------------------------------------------------------------------------
(R)                    6-159          528v2
------------------------------------------------------------------------------
(R)                    6-160            529
------------------------------------------------------------------------------
(R)                    6-161          531v2
------------------------------------------------------------------------------
(R)                    6-162            533
------------------------------------------------------------------------------
(R)                    6-163            534
------------------------------------------------------------------------------
(R)                    6-164            535
------------------------------------------------------------------------------
(R)                    6-165            536
------------------------------------------------------------------------------
(R)                    6-166            537
------------------------------------------------------------------------------
(R)                    6-167            538
------------------------------------------------------------------------------
(R)                    6-168          539v2
------------------------------------------------------------------------------
(R)                    6-170            540
------------------------------------------------------------------------------
(R)                    6-171          541v2
------------------------------------------------------------------------------
(R)                    6-172            542
------------------------------------------------------------------------------
(CR)                   6-173          544v2
------------------------------------------------------------------------------
(R)                    6-176            547
------------------------------------------------------------------------------
(R)                    6-177            548
------------------------------------------------------------------------------
(R)                    6-180            549
------------------------------------------------------------------------------
(R)                    6-181          550v2
------------------------------------------------------------------------------
(R)                    6-182          551v2
------------------------------------------------------------------------------
(R)                    6-184          552v2
------------------------------------------------------------------------------
(R)                    6-185          553v2
------------------------------------------------------------------------------
(R)                    6-186            554                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            16 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    6-187            555                    [
------------------------------------------------------------------------------
(R)                    6-189          556v2
------------------------------------------------------------------------------
(O)                    6-190          557v2
------------------------------------------------------------------------------
(R)                    6-192            558
------------------------------------------------------------------------------
(R)                    6-194          559v2
------------------------------------------------------------------------------
(O)                    6-195          560v2
------------------------------------------------------------------------------
(R)                    6-196            561
------------------------------------------------------------------------------
(R)                    6-198          562v2
------------------------------------------------------------------------------
(R)                    6-200          564v2
------------------------------------------------------------------------------
(R)                    6-201          566v2
------------------------------------------------------------------------------
(R)                    6-203          567v2
------------------------------------------------------------------------------
(R)                    6-205          568v2
------------------------------------------------------------------------------
(O)                    6-206          569v2
------------------------------------------------------------------------------
(R)                    6-208            570
------------------------------------------------------------------------------
(R)                    6-210          571v2
------------------------------------------------------------------------------
(O)                    6-211          572v2
------------------------------------------------------------------------------
(R)                    6-212            573
------------------------------------------------------------------------------
(R)                    6-214          574v2
------------------------------------------------------------------------------
(R)                    6-216          576v2
------------------------------------------------------------------------------
(R)                    6-217          578v2
------------------------------------------------------------------------------
(R)                    6-219          579v2
------------------------------------------------------------------------------
(R)                    6-220          580v2
------------------------------------------------------------------------------
(R)                    6-222          581v2
------------------------------------------------------------------------------
(R)                    6-223          582v2
------------------------------------------------------------------------------
(R)                    6-224          583v2
------------------------------------------------------------------------------
(R)                    6-228          584v2
------------------------------------------------------------------------------
(R)                    6-236          585v2
------------------------------------------------------------------------------
(R)                    6-229          586v2
------------------------------------------------------------------------------
(R)                    6-238          587v2
------------------------------------------------------------------------------
(R)                    6-239          588v2
------------------------------------------------------------------------------
(CR)                   6-241          589v2
------------------------------------------------------------------------------
(CR)                   6-240          591v2
------------------------------------------------------------------------------
(R)                    6-247          592v2
------------------------------------------------------------------------------
(CR)                   6-245          593v2
------------------------------------------------------------------------------
(O)                    6-248          595v2
------------------------------------------------------------------------------
(R)                    6-251          596v2
------------------------------------------------------------------------------
(O)                    6-252          597v2
------------------------------------------------------------------------------
(R)                    6-253            598
------------------------------------------------------------------------------
(O)                    6-254            599
------------------------------------------------------------------------------
(R)                    6-258          609v2
------------------------------------------------------------------------------
(R)                    6-255          610v2
------------------------------------------------------------------------------
(R)                    6-259          611v2
------------------------------------------------------------------------------
(R)                    6-256            612                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            17 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    6-261          617v2                    [
------------------------------------------------------------------------------
(R)                    6-262          618v2
------------------------------------------------------------------------------
(R)                    6-271            620
------------------------------------------------------------------------------
(R)                    6-263            621
------------------------------------------------------------------------------
(R)                    6-264          622v2
------------------------------------------------------------------------------
(R)                    6-272            623
------------------------------------------------------------------------------
(R)                    6-268            625
------------------------------------------------------------------------------
(R)                    6-265            626
------------------------------------------------------------------------------
(R)                    6-269            627
------------------------------------------------------------------------------
(R)                    6-270            628
------------------------------------------------------------------------------
(R)                    6-266          629v2
------------------------------------------------------------------------------
(R)                    6-273            632
------------------------------------------------------------------------------
(R)                    6-276            633
------------------------------------------------------------------------------
(R)                    6-277            634
------------------------------------------------------------------------------
(R)                    6-282          635v2
------------------------------------------------------------------------------
(R)                    6-279            636
------------------------------------------------------------------------------
(R)                    6-280          637v2
------------------------------------------------------------------------------
(R)                    6-284          638v2
------------------------------------------------------------------------------
(R)                    6-278          639v2
------------------------------------------------------------------------------
(R)                    6-288          640v2
------------------------------------------------------------------------------
(R)                    6-289            641
------------------------------------------------------------------------------
(O)                    6-290            642
------------------------------------------------------------------------------
(O)                    6-291          643v2
------------------------------------------------------------------------------
(R)                    6-293          645v2
------------------------------------------------------------------------------
(O)                    6-294            646
------------------------------------------------------------------------------
(O)                    6-295            647
------------------------------------------------------------------------------
(R)                    6-296          648v2
------------------------------------------------------------------------------
(R)                    6-297            649
------------------------------------------------------------------------------
(CR)                   6-298            650
------------------------------------------------------------------------------
(R)                    6-299            651
------------------------------------------------------------------------------
(R)                    6-300            653
------------------------------------------------------------------------------
(R)                    6-301            655
------------------------------------------------------------------------------
(R)                    6-302            656
------------------------------------------------------------------------------
(R)                    6-303            657
------------------------------------------------------------------------------
(CR)                   6-304            658
------------------------------------------------------------------------------
(O)                    6-305          659v2
------------------------------------------------------------------------------
(R)                    6-306            660
------------------------------------------------------------------------------
(R)                    6-307            661
------------------------------------------------------------------------------
(R)                    6-308            662
------------------------------------------------------------------------------
(R)                    6-309            663
------------------------------------------------------------------------------
(R)                    6-310            664
------------------------------------------------------------------------------
(O)                    6-311            665
------------------------------------------------------------------------------
(R)                    6-312            666                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            18 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    6-313            667                    [
------------------------------------------------------------------------------
(R)                    6-314            668
------------------------------------------------------------------------------
(R)                    6-315            669
------------------------------------------------------------------------------
(R)                    6-316            670
------------------------------------------------------------------------------
(R)                    6-317            671
------------------------------------------------------------------------------
(R)                    6-318            672
------------------------------------------------------------------------------
(R)                    6-319            673
------------------------------------------------------------------------------
(R)                    6-320            674
------------------------------------------------------------------------------
(R)                    6-321            675
------------------------------------------------------------------------------
(R)                    6-322            676
------------------------------------------------------------------------------
(R)                    6-323            677
------------------------------------------------------------------------------
(R)                    6-324            678
------------------------------------------------------------------------------
(R)                    6-325            679
------------------------------------------------------------------------------
(CR)                   6-326            680
------------------------------------------------------------------------------
(R)                    6-327            681
------------------------------------------------------------------------------
(R)                    6-330            682
------------------------------------------------------------------------------
(R)                    6-328          683v2
------------------------------------------------------------------------------
(CR)                   6-331            685
------------------------------------------------------------------------------
(CR)                   6-332            686
------------------------------------------------------------------------------
(O)                    6-333            687
------------------------------------------------------------------------------
(R)                    6-334            688
------------------------------------------------------------------------------
(R)                    6-335            689
------------------------------------------------------------------------------
(O)                    6-336            690
------------------------------------------------------------------------------
(R)                    6-337          691v2
------------------------------------------------------------------------------
(O)                    6-338            693
------------------------------------------------------------------------------
(O)                    6-339          694v2
------------------------------------------------------------------------------
(R)                    6-274          695v2
------------------------------------------------------------------------------
(O)                    6-275          703v2
------------------------------------------------------------------------------
(R)                    6-341            706
------------------------------------------------------------------------------
(O)                    6-342            707
------------------------------------------------------------------------------
(O)                    6-343            709
------------------------------------------------------------------------------
(R)                    6-344            710
------------------------------------------------------------------------------
(CR)                   6-345            711
------------------------------------------------------------------------------
(R)                    6-346            712
------------------------------------------------------------------------------
(O)                    6-347            713
------------------------------------------------------------------------------
(O)                    6-348            714
------------------------------------------------------------------------------
(CR)                   6-349            715
------------------------------------------------------------------------------
(R)                    6-350            716
------------------------------------------------------------------------------
(R)                    6-351            717
------------------------------------------------------------------------------
(R)                    6-352            718
------------------------------------------------------------------------------
(R)                    6-353            719
------------------------------------------------------------------------------
(O)                    6-354            720
------------------------------------------------------------------------------
(CR)                   6-355            721                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            19 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(O)                    6-356            722                    [
------------------------------------------------------------------------------
(O)                    6-357            723
------------------------------------------------------------------------------
(O)                    6-358            724
------------------------------------------------------------------------------
(R)                    6-367          725v2
------------------------------------------------------------------------------
(R)                    6-370            728
------------------------------------------------------------------------------
(CR)                   6-371            729
------------------------------------------------------------------------------
(O)                    6-372            730
------------------------------------------------------------------------------
(R)                    6-376          731v2
------------------------------------------------------------------------------
(R)                    6-382          732v2
------------------------------------------------------------------------------
(R)                    6-380          735v2
------------------------------------------------------------------------------
(R)                    6-381          736v2
------------------------------------------------------------------------------
(R)                    6-386            737
------------------------------------------------------------------------------
(R)                    6-389            738
------------------------------------------------------------------------------
(R)                    6-390            739
------------------------------------------------------------------------------
(R)                    6-359          740v2
------------------------------------------------------------------------------
(R)                    6-360            741
------------------------------------------------------------------------------
(R)                    6-361            743
------------------------------------------------------------------------------
(R)                    6-363            744
------------------------------------------------------------------------------
(R)                    6-362            745
------------------------------------------------------------------------------
(R)                    6-364            746
------------------------------------------------------------------------------
(R)                    6-365            747
------------------------------------------------------------------------------
(R)                    6-366          748v2
------------------------------------------------------------------------------
(O)                    6-391            749
------------------------------------------------------------------------------
(R)                    6-392            750
------------------------------------------------------------------------------
(R)                    6-393          751v2
------------------------------------------------------------------------------
(R)                    6-395            755
------------------------------------------------------------------------------
(R)                    6-394            756
------------------------------------------------------------------------------
(O)                    6-396          757v2
------------------------------------------------------------------------------
(R)                    6-398            759
------------------------------------------------------------------------------
(R)                    6-399            760
------------------------------------------------------------------------------
(O)                      7-1            761
------------------------------------------------------------------------------
(R)                      7-2            762
------------------------------------------------------------------------------
(R)                      7-3            763
------------------------------------------------------------------------------
(R)                      7-4            764
------------------------------------------------------------------------------
(R)                      7-5            765
------------------------------------------------------------------------------
(R)                      7-6            766
------------------------------------------------------------------------------
(R)                      7-7            767
------------------------------------------------------------------------------
(R)                      7-8            768
------------------------------------------------------------------------------
(R)                      7-9            771
------------------------------------------------------------------------------
(R)                     7-10            772                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            20 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     7-11            773                    [
------------------------------------------------------------------------------
(R)                     7-12            774
------------------------------------------------------------------------------
(O)                     7-13            775
------------------------------------------------------------------------------
(R)                      8-1            776
------------------------------------------------------------------------------
(R)                      8-2            777
------------------------------------------------------------------------------
(R)                      8-3            778
------------------------------------------------------------------------------
(O)                      8-4            779
------------------------------------------------------------------------------
(R)                      8-5            780
------------------------------------------------------------------------------
(R)                      8-6            781
------------------------------------------------------------------------------
(R)                      8-7            782
------------------------------------------------------------------------------
(R)                      8-8            783
------------------------------------------------------------------------------
(R)                      8-9            784
------------------------------------------------------------------------------
(R)                     8-10            785
------------------------------------------------------------------------------
(R)                     8-11            786
------------------------------------------------------------------------------
(R)                     8-12            787
------------------------------------------------------------------------------
(R)                     8-13            788
------------------------------------------------------------------------------
(R)                     8-14            789
------------------------------------------------------------------------------
(R)                     8-15            790
------------------------------------------------------------------------------
(R)                     8-16            791
------------------------------------------------------------------------------
(CR)                    8-17            792
------------------------------------------------------------------------------
(CR)                    8-18            793
------------------------------------------------------------------------------
(R)                     8-19            794
------------------------------------------------------------------------------
(R)                     8-20          795v2
------------------------------------------------------------------------------
(R)                     8-22            796
------------------------------------------------------------------------------
(R)                     8-23            797
------------------------------------------------------------------------------
(R)                     8-24            798
------------------------------------------------------------------------------
(R)                     8-25            799
------------------------------------------------------------------------------
(R)                     8-26            800
------------------------------------------------------------------------------
(R)                     8-27            801
------------------------------------------------------------------------------
(R)                     8-28            802
------------------------------------------------------------------------------
(R)                     8-29            803
------------------------------------------------------------------------------
(R)                     8-30            804
------------------------------------------------------------------------------
(R)                     8-31            805
------------------------------------------------------------------------------
(R)                     8-32            806
------------------------------------------------------------------------------
(R)                     8-33            807
------------------------------------------------------------------------------
(R)                     8-34            808
------------------------------------------------------------------------------
(R)                     8-35            809
------------------------------------------------------------------------------
(R)                     8-36            810
------------------------------------------------------------------------------
(R)                     8-37            811
------------------------------------------------------------------------------
(R)                     8-38            812
------------------------------------------------------------------------------
(R)                     8-39            813
------------------------------------------------------------------------------
(R)                     8-40            814
------------------------------------------------------------------------------
(R)                     8-41            815                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            21 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     8-42            816                    [
------------------------------------------------------------------------------
(R)                     8-43            817
------------------------------------------------------------------------------
(CR)                    8-44            818
------------------------------------------------------------------------------
(R)                     8-45          819v2
------------------------------------------------------------------------------
(O)                     8-46            820
------------------------------------------------------------------------------
(O)                     8-47            821
------------------------------------------------------------------------------
(R)                     8-48            822
------------------------------------------------------------------------------
(R)                     8-49            823
------------------------------------------------------------------------------
(R)                     8-50            824
------------------------------------------------------------------------------
(R)                     8-51            825
------------------------------------------------------------------------------
(R)                     8-52            826
------------------------------------------------------------------------------
(R)                     8-53            827
------------------------------------------------------------------------------
(R)                     8-54            828
------------------------------------------------------------------------------
(R)                     8-55            829
------------------------------------------------------------------------------
(R)                     8-56            830
------------------------------------------------------------------------------
(R)                     8-57            831
------------------------------------------------------------------------------
(R)                     8-58            832
------------------------------------------------------------------------------
(R)                     8-59            833
------------------------------------------------------------------------------
(R)                     8-60            834
------------------------------------------------------------------------------
(O)                     8-61            835
------------------------------------------------------------------------------
(R)                     8-62            836
------------------------------------------------------------------------------
(R)                     8-63            837
------------------------------------------------------------------------------
(R)                     8-64            838
------------------------------------------------------------------------------
(R)                     8-65            839
------------------------------------------------------------------------------
(R)                     8-66            840
------------------------------------------------------------------------------
(R)                     8-67            841
------------------------------------------------------------------------------
(R)                     8-68            842
------------------------------------------------------------------------------
(R)                     8-69            843
------------------------------------------------------------------------------
(R)                     8-70            844
------------------------------------------------------------------------------
(R)                     8-71            845
------------------------------------------------------------------------------
(R)                     8-72            846
------------------------------------------------------------------------------
(R)                     8-73            847
------------------------------------------------------------------------------
(R)                     8-74            848
------------------------------------------------------------------------------
(R)                     8-75            849
------------------------------------------------------------------------------
(R)                     8-76          850v2
------------------------------------------------------------------------------
(R)                     8-77            851
------------------------------------------------------------------------------
(R)                     8-78            852
------------------------------------------------------------------------------
(R)                     8-79            853
------------------------------------------------------------------------------
(R)                     8-80            854
------------------------------------------------------------------------------
(R)                     8-81            855
------------------------------------------------------------------------------
(R)                     8-82            856
------------------------------------------------------------------------------
(R)                     8-83            857
------------------------------------------------------------------------------
(R)                     8-84            858                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            22 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                     8-85            859                    [
------------------------------------------------------------------------------
(R)                     8-86            860
------------------------------------------------------------------------------
(R)                     8-87            861
------------------------------------------------------------------------------
(R)                     8-88            862
------------------------------------------------------------------------------
(R)                     8-89            863
------------------------------------------------------------------------------
(R)                     8-90            864
------------------------------------------------------------------------------
(R)                     8-91            865
------------------------------------------------------------------------------
(R)                     8-92            866
------------------------------------------------------------------------------
(R)                     8-93            867
------------------------------------------------------------------------------
(R)                     8-94            868
------------------------------------------------------------------------------
(R)                     8-95            869
------------------------------------------------------------------------------
(O)                     8-96            870
------------------------------------------------------------------------------
(O)                     8-97            871
------------------------------------------------------------------------------
(O)                     8-98            872
------------------------------------------------------------------------------
(R)                     8-99            873
------------------------------------------------------------------------------
(O)                    8-100            874
------------------------------------------------------------------------------
(R)                    8-101            875
------------------------------------------------------------------------------
(R)                    8-102            876
------------------------------------------------------------------------------
(R)                    8-103            877
------------------------------------------------------------------------------
(R)                    8-104            878
------------------------------------------------------------------------------
(R)                    8-105            879
------------------------------------------------------------------------------
(O)                    8-106            880
------------------------------------------------------------------------------
(R)                    8-107            881
------------------------------------------------------------------------------
(R)                    8-108            882
------------------------------------------------------------------------------
(R)                    8-109            883
------------------------------------------------------------------------------
(R)                    8-110            884
------------------------------------------------------------------------------
(R)                    8-111            885
------------------------------------------------------------------------------
(R)                    8-112            886
------------------------------------------------------------------------------
(R)                    8-113            887
------------------------------------------------------------------------------
(R)                    8-114            888
------------------------------------------------------------------------------
(R)                    8-115            889
------------------------------------------------------------------------------
(R)                    8-116            890
------------------------------------------------------------------------------
(R)                    8-117            891
------------------------------------------------------------------------------
(CR)                   8-118            892
------------------------------------------------------------------------------
(R)                    8-119            893
------------------------------------------------------------------------------
(R)                    8-121            894
------------------------------------------------------------------------------
(R)                    8-122            895
------------------------------------------------------------------------------
(R)                    8-123            896
------------------------------------------------------------------------------
(R)                    8-124            897
------------------------------------------------------------------------------
(R)                    8-125            898
------------------------------------------------------------------------------
(R)                    8-126            899
------------------------------------------------------------------------------
(R)                    8-127          900v2
------------------------------------------------------------------------------
(R)                    8-128            901                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            23 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    8-129            902                    [
------------------------------------------------------------------------------
(R)                     3-54            903
------------------------------------------------------------------------------
(R)                     3-61            904
------------------------------------------------------------------------------
(R)                     3-68            905
------------------------------------------------------------------------------
(R)                     3-72            906
------------------------------------------------------------------------------
(R)                     3-73            907
------------------------------------------------------------------------------
(R)                     3-99            908
------------------------------------------------------------------------------
(O)                    3-112            909
------------------------------------------------------------------------------
(CR)                    4-20            910
------------------------------------------------------------------------------
(R)                      5-4            911
------------------------------------------------------------------------------
(R)                      5-5            912
------------------------------------------------------------------------------
(CR)                    5-48            913
------------------------------------------------------------------------------
(R)                     5-51            914
------------------------------------------------------------------------------
(CR)                    5-52            915
------------------------------------------------------------------------------
(R)                     5-53            916
------------------------------------------------------------------------------
(O)                     5-83            917
------------------------------------------------------------------------------
(R)                     5-95            918
------------------------------------------------------------------------------
(R)                    5-102            919
------------------------------------------------------------------------------
(R)                    5-103            920
------------------------------------------------------------------------------
(R)                    5-113            921
------------------------------------------------------------------------------
(R)                    5-118            922
------------------------------------------------------------------------------
(R)                    5-119            923
------------------------------------------------------------------------------
(R)                    5-120            924
------------------------------------------------------------------------------
(R)                    5-121            925
------------------------------------------------------------------------------
(R)                    5-125            926
------------------------------------------------------------------------------
(R)                    5-128            927
------------------------------------------------------------------------------
(O)                    5-135            928
------------------------------------------------------------------------------
(O)                    5-138            929
------------------------------------------------------------------------------
(R)                    5-143            930
------------------------------------------------------------------------------
(R)                    5-208            931
------------------------------------------------------------------------------
(R)                    5-222            932
------------------------------------------------------------------------------
(R)                    5-223            933
------------------------------------------------------------------------------
(R)                    5-224            934
------------------------------------------------------------------------------
(R)                    5-225            935
------------------------------------------------------------------------------
(O)                    5-226            936
------------------------------------------------------------------------------
(O)                    5-230            937
------------------------------------------------------------------------------
(R)                      6-3            938                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            24 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 



------------------------------------------------------------------------------
(R)                      6-4            939                    [
------------------------------------------------------------------------------
(O)                     6-53            940
------------------------------------------------------------------------------
(R)                     6-67            941
------------------------------------------------------------------------------
(CR)                    6-68            942
------------------------------------------------------------------------------
(CR)                    6-69            943
------------------------------------------------------------------------------
(R)                     6-71            944
------------------------------------------------------------------------------
(R)                     6-74            945
------------------------------------------------------------------------------
(R)                     6-75            946
------------------------------------------------------------------------------
(R)                     6-76            947
------------------------------------------------------------------------------
(R)                     6-77            948
------------------------------------------------------------------------------
(R)                     6-79            949
------------------------------------------------------------------------------
(R)                     6-82            950
------------------------------------------------------------------------------
(R)                    6-169            951
------------------------------------------------------------------------------
(CR)                   6-174            952
------------------------------------------------------------------------------
(O)                    6-175            953
------------------------------------------------------------------------------
(R)                    6-178            954
------------------------------------------------------------------------------
(R)                    6-179            955
------------------------------------------------------------------------------
(O)                    6-183            956
------------------------------------------------------------------------------
(CR)                   6-188            957
------------------------------------------------------------------------------
(R)                    6-191            958
------------------------------------------------------------------------------
(O)                    6-193            959
------------------------------------------------------------------------------
(R)                    6-197            960
------------------------------------------------------------------------------
(R)                    6-199            961
------------------------------------------------------------------------------
(O)                    6-202            962
------------------------------------------------------------------------------
(CR)                   6-204            963
------------------------------------------------------------------------------
(R)                    6-207            964
------------------------------------------------------------------------------
(O)                    6-209            965
------------------------------------------------------------------------------
(R)                    6-213            966
------------------------------------------------------------------------------
(R)                    6-215            967
------------------------------------------------------------------------------
(O)                    6-218            968
------------------------------------------------------------------------------
(R)                    6-221            969
------------------------------------------------------------------------------
(CR)                   6-225            970
------------------------------------------------------------------------------
(R)                    6-226            971
------------------------------------------------------------------------------
(R)                    6-227            972
------------------------------------------------------------------------------
(R)                    6-230            973
------------------------------------------------------------------------------
(R)                    6-231            974
------------------------------------------------------------------------------
(R)                    6-232            975
------------------------------------------------------------------------------
(CR)                   6-233            976
------------------------------------------------------------------------------
(R)                    6-234            977
------------------------------------------------------------------------------
(R)                    6-235            978
------------------------------------------------------------------------------
(R)                    6-237            979
------------------------------------------------------------------------------
(R)                    6-242            980
------------------------------------------------------------------------------
(R)                    6-243            981                           **]
------------------------------------------------------------------------------

_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            25 of 26


<PAGE>
Positron Fiber Systems    Proprietary

                                  **Confidential treatment has been requested 
                                    with respect to the information contained 
                                      within the "[**]" markings. Such marked 
                                  portions have been omitted from this filing 
                                      and have been filed separately with the 
                                           Securities and Exchange Commission 


------------------------------------------------------------------------------
(R)                    6-244            982                    [
------------------------------------------------------------------------------
(R)                    6-246            983
------------------------------------------------------------------------------
(CR)                   6-249            984
------------------------------------------------------------------------------
(CR)                   6-250            985
------------------------------------------------------------------------------
(R)                    6-257            986
------------------------------------------------------------------------------
(R)                    6-260            987
------------------------------------------------------------------------------
(R)                    6-267            988
------------------------------------------------------------------------------
(R)                    6-281            989
------------------------------------------------------------------------------
(O)                    6-283            990
------------------------------------------------------------------------------
(R)                    6-285            991
------------------------------------------------------------------------------
(O)                    6-286            992
------------------------------------------------------------------------------
(O)                    6-287            993
------------------------------------------------------------------------------
(O)                    6-292            994
------------------------------------------------------------------------------
(R)                    6-329            995
------------------------------------------------------------------------------
(R)                    6-340            996
------------------------------------------------------------------------------
(R)                    6-368            997
------------------------------------------------------------------------------
(CR)                   6-369            998
------------------------------------------------------------------------------
(CR)                   6-373            999
------------------------------------------------------------------------------
(R)                    6-374           1000
------------------------------------------------------------------------------
(O)                    6-375           1001
------------------------------------------------------------------------------
(CR)                   6-377           1002
------------------------------------------------------------------------------
(R)                    6-378           1003
------------------------------------------------------------------------------
(O)                    6-379           1004
------------------------------------------------------------------------------
(R)                    6-383           1005
------------------------------------------------------------------------------
(R)                    6-384           1006
------------------------------------------------------------------------------
(CR)                   6-385           1007
------------------------------------------------------------------------------
(R)                    6-387           1008
------------------------------------------------------------------------------
(CR)                   6-388           1009
------------------------------------------------------------------------------
(O)                    6-397           1010
------------------------------------------------------------------------------
(CR)                    8-21           1011
------------------------------------------------------------------------------
(R)                    8-120           1012                           **]
------------------------------------------------------------------------------


_______________________________________________
OSIRIS SONET OC3 GR-1400-CORE Compliance Report


Issue 1.0, October 24, 1996            26 of 26