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                                 PROJECT ISLAND


                                      

                        TRANSITIONAL SERVICES AGREEMENT


                                      

                                  JULY 15, 2002





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                        TRANSITIONAL SERVICES AGREEMENT



     This Transitional Services Agreement (the "Agreement") is entered into
between Tekelec, a California corporation ("Tekelec"), and Catapult
Communications Corporation, a Nevada corporation ("Catapult"). Tekelec and
Catapult are sometimes referred to herein individually as a "party" or together
as the "parties." This Agreement is entered into on July 15, 2002, in connection
with the execution of and pursuant to the Asset Purchase Agreement (as defined
below) and shall become effective upon the Closing Date (as defined below).



                                    RECITALS



     WHEREAS, Tekelec and Catapult are parties to the Asset Purchase Agreement
pursuant to which, among other things, Catapult will, at the Closing, acquire
the Acquired Assets, all on the terms and conditions set forth therein; and


     WHEREAS, the parties seek an orderly transition of the Business from
Tekelec to Catapult following the Closing;


     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereby agree as
follows:



                                   ARTICLE 1

                                  DEFINITIONS


     1.1 For the purpose of this Agreement, the following capitalized terms
shall have the following meanings:


             (a) "ACQUIRED ASSETS" shall have the meaning set forth in Section
1.1(b) of the Asset Purchase Agreement.


             (b) "ADDITIONAL SERVICES" shall have the meaning set forth in
SECTION 3.4.


             (c) "ANCILLARY AGREEMENTS" shall have the meaning set forth in
Section 1.1(g) of the Asset Purchase Agreement.


             (d) "ASSET PURCHASE AGREEMENT" shall mean that certain Asset
Purchase Agreement dated July 15, 2002 between Tekelec and Catapult.


             (e) "BUSINESS" shall have the meaning set forth in Section 1.1(n)
of the Asset Purchase Agreement.




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             (f) "CLOSING" shall HAVE THE MEANING SET FORTH IN SECTION 1.1(CC)
OF THE ASSET PURCHASE AGREEMENT.


             (g) "CLOSING DATE" shall have the meaning set forth in
Section 1.1(ee) of the Asset Purchase Agreement.


             (h) "FORCE MAJEURE" shall have the meaning set forth in ARTICLE 11
hereof.


             (i) "IMPRACTICABLE" or "IMPRACTICABILITY" shall have the meaning
set forth in ARTICLE 11.


             (j) "NDD" shall mean Tekelec's Network Diagnostics Division.


             (k) "NSD" shall mean Tekelec's Network Systems Division.


             (l) "PRIME RATE" shall mean highest "Prime Rate" as published daily
in THE WALL STREET JOURNAL under the heading "Money Rates."


             (m) "SERVICE(S)" shall have the meaning set forth in SECTION 3.1
hereof.


             (n) "SUBCONTRACTOR" shall have the meaning set forth in ARTICLE 9
hereof.


             (o) "TRANSITION SERVICE SCHEDULE" shall have the meaning set forth
in SECTION 2.1 hereof.



                                   ARTICLE 2

                          TRANSITION SERVICE SCHEDULES


     2.1 DEFINITION. This Agreement will govern individual transitional services
agreed to be provided by Tekelec to Catapult hereunder, and the details of which
are set forth in the Transition Service Schedules (each transition service
schedule, a "Transition Service Schedule") attached to this Agreement. Each
Service shall be covered by this Agreement upon execution of a Transition
Service Schedule with respect thereto in substantially the form attached hereto.


     2.2 CONTENT. Each Transition Service Schedule shall be signed by a duly
authorized representative of each party and shall set forth, among other things,
(i) the time period during which the Services set forth therein will be provided
if different from the term of this Agreement (determined pursuant to ARTICLE 4
hereof); (ii) a reasonably detailed description of the Services to be provided;
(iii) the fees and charges or methodology for determining the fees and charges
to be paid by Catapult to Tekelec for the performance of the Services covered
thereby; and (iv) any other terms applicable thereto. Obligations regarding each
Transition Service Schedule attached hereto upon signing of this Agreement or at
or prior to the Closing shall be effective upon the Closing, or, if


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a particular Transition Service Schedule is amended or a new Transition Service
Schedule is executed after the Closing, the obligations created by such
amendment or new Transition Service Schedule shall be effective upon execution
of such amendment or such new Transition Service Schedule or as of such other
effective date as is set forth therein. The Transition Service Schedules shall
be deemed included within the definition of this "Agreement" and incorporated
herein wherever reference to this Agreement is made. In the event of any
inconsistency between the terms of this Agreement and the terms of any
Transition Service Schedule, the terms of the Transition Service Schedule shall
prevail.



                                   ARTICLE 3

                                    SERVICES


     3.1 SERVICES GENERALLY. For purposes of assisting in implementing an
orderly transition of the Business to Catapult from and after the Closing, and
except as otherwise provided herein or in a Transition Service Schedule, for the
term determined pursuant to ARTICLE 4 hereof, Tekelec shall provide or cause to
be provided to Catapult the services described in the Transition Service
Schedules attached hereto. The service(s) described on a single Transition
Service Schedule shall be referred to herein as a "Service." Collectively, the
services described on all the Transition Service Schedules (including Additional
Services) shall be referred to herein as "Services."


     3.2 SERVICE BOUNDARIES. Except as provided in a Transition Service Schedule
for a specific Service: (i) Tekelec shall be required to provide the Services
only at the locations in the United States of America at which such Services are
being provided by Tekelec for or as part of the Business immediately prior to
the Closing Date; and (ii) the Services will be available only for purposes of
conducting the Business substantially in the manner in which it was conducted
during the three months prior to the Closing Date.


     3.3 ADDITIONAL RESOURCES. Except as provided in a Transition Service
Schedule for a specific Service, in providing the Services, Catapult
acknowledges and agrees that Tekelec shall not be obligated to: (i) hire any
additional employees; (ii) maintain the employment of any specific employee;
(iii) purchase, lease or license any additional equipment or software; or (iv)
pay any costs related to the transfer or conversion of the Business to Catapult.
To Tekelec's knowledge, none of actions described in immediately preceding
clauses (i), (ii) or (iii) will be required for Tekelec to perform the Services.


     3.4 ADDITIONAL SERVICES. From time to time after the signing of this
Agreement, the parties may identify and reasonably agree upon Services other
than those described on the Transition Service Schedules attached hereto at
signing that Tekelec will provide to Catapult in accordance with the terms of
this Agreement (the "Additional Services"). In the event the parties identify
and agree upon any such services, the parties shall execute additional
Transition Service Schedules for such Additional Services pursuant to ARTICLE 2
and such Additional Services shall be included within the Services to be
rendered hereunder. In the event Catapult or Tekelec requests that the


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parties enter into or amend a Transition Services Schedule to provide for any
such Additional Service which is reasonably deemed by such requesting party to
be either incidental to the Services already being performed by Tekelec
hereunder or necessary or appropriate to effectuate an orderly transition of the
Business to Catapult, Tekelec and Catapult each agree to negotiate in good faith
to reach agreement on reasonable charges and other terms and conditions for the
performance of any such services by Tekelec hereunder; PROVIDED, HOWEVER, that
in the event the performance of such services would significantly disrupt
Tekelec's operations or materially increase the scope of its responsibilities or
materially increase the cost of its performance under this Agreement, Tekelec
shall not be obligated to provide such services if the parties cannot reach
agreement on such terms and conditions after such good faith negotiations. In no
event will Tekelec be required to perform any Service to the extent such Service
does not relate to the continued conduct by Catapult of the Business as it was
conducted during the three months prior to the Closing Date.



                                   ARTICLE 4

                                      TERM


     The term of this Agreement shall commence on the Closing Date and shall
remain in effect until two years after the Closing Date (the "Expiration Date"),
unless earlier terminated under ARTICLE 7. This Agreement may be extended by the
parties in writing, either in whole or with respect to one or more of the
Services; PROVIDED, however, that any such extension shall only apply to the
Services for which this Agreement is extended. The parties shall be deemed to
have extended this Agreement with respect to a specific Service if the
Transition Service Schedule for such Service specifies a completion date beyond
the aforementioned Expiration Date. The parties may agree on an earlier
expiration date respecting a specific Service by specifying such date in the
Transition Service Schedule for that Service.



                                   ARTICLE 5

                                  COMPENSATION


     5.1 CHARGES FOR SERVICES. Catapult shall pay Tekelec the charges, if any,
set forth on the Transition Service Schedules for each of the Services listed
therein. Such fees shall include costs, as set forth in or as determined using
the process described in such Transition Service Schedule for the determination
of costs. The parties shall use good faith efforts to discuss and adjust pricing
in any situation in which the actual charge for a Service is reasonably expected
to exceed the estimated charge, if any, set forth on a Transition Service
Schedule for a particular Service; provided, however, that the incurrence of
charges in excess of any such estimate on such Transition Service Schedule shall
not justify stopping the provision of, or payment for, Services under this
Agreement.


     5.2 PAYMENT TERMS. Tekelec shall bill Catapult monthly for all charges
pursuant to this Agreement. Such bills shall be accompanied by reasonable
documentation or other reasonable


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explanation supporting such charges. Catapult shall pay Tekelec for all Services
provided hereunder within 30 days after receipt of an invoice therefor. Late
payments shall bear interest at the lesser of 18% per annum or the maximum rate
allowed by law.


     5.3 PERFORMANCE UNDER THE ASSET PURCHASE AGREEMENT. Notwithstanding
anything to the contrary contained herein, Catapult shall not be charged under
this Agreement for any commitments that are specifically required to be
performed under the Asset Purchase Agreement and any such other commitments
shall be honored and any charge therefore levied in accordance with the terms of
the Asset Purchase Agreement.


     5.4 ERROR CORRECTION; TRUE-UPS; ACCOUNTING. The parties shall reasonably
agree in writing on a process and procedure for conducting internal audits and
making adjustments to charges as a result of the movement of employees and
functions between parties, the discovery of errors or omissions in charges, as
well as a true-up of amounts owed. In no event shall such processes and
procedures extend beyond two (2) years after completion of a Service.



                                   ARTICLE 6

                     GENERAL OBLIGATIONS; STANDARD OF CARE


     6.1 PERFORMANCE METRICS: TEKELEC. Subject to SECTION 3.3 and all other
terms and conditions of this Agreement, Tekelec shall maintain sufficient
resources to perform its obligations hereunder and under the Transition Service
Schedules. Specific performance metrics for Tekelec for a specific Service may
be set forth in the corresponding Transition Service Schedule. Where none is set
forth, Tekelec shall use commercially reasonable efforts to provide Services in
accordance with Tekelec's applicable policies, procedures and practices in
effect immediately before the Closing Date relating to or in connection with the
Business and shall exercise not less than the same degree of care and skill as
it generally exercises in performing similar services for itself.


     6.2 PERFORMANCE METRICS: CATAPULT. Specific performance metrics for
Catapult for a specific Service may be set forth in the corresponding Transition
Service Schedule. Where none is set forth, Catapult shall use reasonable
efforts, in connection with receiving Services, to follow the policies,
procedures and practices in effect before the Closing Date and shall provide
information and documentation sufficient for Tekelec to perform the Services as
they were performed before the Closing Date and make available, as reasonably
requested by Tekelec, adequate personnel and timely decisions, approvals and
acceptances in order that Tekelec may accomplish its obligations hereunder in a
timely manner.


     6.3 TRANSITIONAL NATURE OF SERVICES; CHANGES. The parties acknowledge the
transitional nature of the Services and that Tekelec may make changes from time
to time in the manner of performing the Services if Tekelec is making similar
changes in performing similar services for itself (which condition shall not
apply if Tekelec does not provide similar services for itself) and if


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Tekelec furnishes to Catapult not less than 45 days prior written notice
regarding such changes; PROVIDED, HOWEVER that Catapult may reasonably waive
such written notice.


     6.4 RESPONSIBILITY FOR ERRORS; DELAYS. Tekelec's sole responsibility to
Catapult:


             (a) for errors or omissions in Services, other than errors or
omissions attributable to Tekelec's gross negligence or willful misconduct,
shall be to furnish correct information, payment and/or adjustment in the
Services, at no additional cost or expense to Catapult, provided that Catapult
must advise Tekelec in writing of any such error or omission of which it becomes
aware within 30 days of becoming so aware and, in any event, within 90 days
following the expiration or earlier termination of this Agreement; and


             (b) in the event of Impracticability, shall be to use commercially
reasonable efforts to perform any portion of the Services which are not
Impracticable and/or to resume performing the Services which are or have become
Impracticable as promptly as reasonably practicable in accordance with the terms
and conditions hereof, provided that in no event shall Tekelec be required to
perform Services after the Expiration Date or the date of any earlier
termination of this Agreement unless otherwise agreed to by Tekelec in writing.


             (c) Notwithstanding the foregoing, Tekelec shall have no liability
for failure to comply with the standard of care set forth in this Agreement for
performance or provision of any of the Services to the extent Tekelec reasonably
requests but does not obtain authorization from Catapult to incur any reasonable
cost necessary to perform or provide any Services not contemplated at the date
of execution of the governing Transition Service Schedule or for any material
changes in Services.


             (d) EXCEPT AS EXPRESSLY PROVIDED HEREIN OR ON ANY TRANSITION
SERVICE SCHEDULE, TEKELEC MAKES NO REPRESENTATIONS OR WARRANTIES WHATSOEVER,
EXPRESS OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
NON-INFRINGEMENT OR ANY OTHER MATTER WITH RESPECT TO ANY SERVICE PROVIDED UNDER
THIS AGREEMENT.


     6.5 GOOD FAITH COOPERATION; CONSENTS. The parties will use good faith
efforts to cooperate with each other in all reasonable respects in all matters
relating to the provision and receipt of Services. Such cooperation shall
include exchanging information, performing true-ups and adjustments, and where
indicated in a Transition Service Schedule or otherwise reasonably necessary to
perform a Service, obtaining all third party consents, licenses, sublicenses or
approvals necessary to permit each party to perform its obligations hereunder
and under any Transition Service Schedule (including, by way of example, not by
way of limitation, rights to use third party software needed for the performance
of Services). The reasonable and documented costs of obtaining such third party
consents, licenses, sublicenses or approvals shall be shared equally by Catapult
and Tekelec unless otherwise indicated in any Transition Service Schedule. The
parties will maintain in accordance with their respective standard document
retention procedures, documentation supporting the information relevant to fee
and cost calculations contained in the Transition Service Schedules


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and cooperate in all reasonable respects with each other in making such
information available as needed in the event of a tax audit, whether in the
United States or any other country.


     6.6 ALTERNATIVES. If Tekelec reasonably believes it is unable to provide
any Service because of a failure to obtain necessary consents, licenses,
sublicenses or approvals pursuant to SECTION 6.5, the parties shall negotiate in
an effort to agree upon a reasonable alternative approach. Until such
alternative approach is found or the problem otherwise resolved to the
satisfaction of the parties, Tekelec shall use its best efforts to continue
providing the Service. To the extent a mutually agreed upon alternative approach
requires payment above and beyond that which is included in Tekelec's charge for
the Service in question, the parties shall share equally in making any such
payment unless they otherwise agree in writing.


     6.7 ASSISTANCE FROM CATAPULT. Catapult agrees to provide Tekelec with
access to its books and records to the extent necessary for Tekelec to perform
the Services, subject to the terms of this Agreement. The parties will use good
faith efforts to cooperate with each other in all matters relating to the
provision and receipt of Services. In particular, during the term of this
Agreement, Catapult shall furnish Tekelec with information in its possession and
control and such other reasonable assistance as is necessary to enable Tekelec
to perform the Services. If Catapult's failure to furnish such information and
assistance renders Tekelec's performance of any item of Service unreasonably
difficult, Tekelec may refuse, or terminate its obligation, to perform that item
of Service without liability or penalty to Tekelec.



                                   ARTICLE 7

                                  TERMINATION


7.1 TERMINATION.


             (a) Catapult may terminate this Agreement, either with respect to
all or with respect to any one or more of the Services provided to Catapult
hereunder, for any reason or for no reason, at any time upon 30 days prior
written notice to Tekelec. In addition, either party may terminate this
Agreement with respect to a specific Service if the other party materially
breaches a material provision with regard to that particular Service and does
not cure such breach (or does not take reasonable steps required under the
circumstances to cure such breach) within 30 days after being given written
notice of the breach, provided that the terminating party has complied with the
provisions of ARTICLE 12 and provided that Tekelec shall have no right to
terminate the Agreement as a result of Catapult's failure to make payment if
Catapult is disputing in good faith its obligation to pay with respect to a
default in payment.


             (b) In the event any proceeding is commenced by or against either
party for the purpose of subjecting its assets to any law relating to bankruptcy
or insolvency or for the appointment of a receiver for the business, property,
affairs or revenues of such party, or if such party makes a general assignment
of its assets for the benefit of creditors, then and in any such event,


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the other party hereto may, at its option without further notice to or demand
of, in addition to all other rights and remedies provided at law or in equity,
terminate this Agreement, effective immediately upon written notice to the other
party hereto, and all rights, privileges and licenses granted or created
hereunder.


             (c) In the event of any termination or expiration of this
Agreement, Catapult shall pay Tekelec for fees and charges payable hereunder for
Services rendered and expenses incurred by Tekelec through the date of such
termination or expiration, unless Catapult is disputing the payment of such fee
and charges in good faith subject to ARTICLE 12, in which case such fees and
charges, if owed, shall be paid promptly upon resolution of such dispute.


     7.2 SURVIVAL. In the event of any termination with respect to one or more,
but less than all Services, this Agreement shall continue in full force and
effect with respect to any Services not subject to such termination in
accordance with the terms of this Agreement.


     7.3 USER IDS, PASSWORDS. Each of the parties shall use good faith efforts
at the termination or expiration of this Agreement, any specific Service
hereunder or any Transition Service Schedule attached hereto to ensure that all
applicable user IDs and passwords issued to such party by the other party are
canceled or returned, as applicable.



                                   ARTICLE 8

                        RELATIONSHIP BETWEEN THE PARTIES


     It is expressly acknowledged that the parties are "independent
contractors," and nothing in this Agreement is intended and nothing shall be
construed to allow either party to exercise control or direction over the manner
or method by which the other party performs its obligations under this
Agreement; provided, that the Services to be provided hereunder shall be
furnished in a manner consistent with the standards governing such Services and
pursuant to the provisions of this Agreement. Each party understands and agrees
that (i) neither party will withhold on behalf of the other party any sums for
income tax, unemployment insurance, social security or any other withholding
pursuant to any law or requirement of any governmental body or make available
any of the benefits afforded to its employees, (ii) all of such payments,
withholdings and benefits, if any, are the sole responsibility of the party
incurring the liability, and (iii) each party will indemnify and hold the other
harmless from any and all loss or liability arising with respect to such
payments, withholdings and benefits, if any.



                                   ARTICLE 9

                                 SUBCONTRACTORS


     Tekelec may engage a "Subcontractor" reasonably acceptable to Catapult to
perform all or any portion of Tekelec's duties under this Agreement, provided
that any such Subcontractor agrees in writing to be bound by confidentiality
obligations at least as protective of Catapult as the terms of


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ARTICLE 10 regarding confidentiality below, and provided further that Tekelec
remains responsible for the performance of such Subcontractor. As used in this
Agreement, "Subcontractor" will mean any individual, partnership, corporation,
firm, association, unincorporated organization, joint venture, trust or other
entity engaged by Tekelec to perform Services hereunder.



                                   ARTICLE 10

                                CONFIDENTIALITY


     The terms of Section 6.6 of the Asset Purchase Agreement shall apply to any
Confidential Information (as defined therein) which is the subject matter of or
is disclosed pursuant to this Agreement.



                                   ARTICLE 11

                                 FORCE MAJEURE


     Each party will be excused for any failure or delay in performing any of
its obligations under this Agreement, other than the obligations of Catapult to
make payments to Tekelec hereunder for services rendered, if such failure or
delay is caused by Force Majeure, provided that Tekelec shall use the same level
of effort it uses to provide similar services internally, and no less than
reasonable efforts, to continue to provide a Service (such an excused failure or
delay in performance is referred to herein as an "Impracticability" or
"Impracticable"). "Force Majeure" means any act of God or the public enemy, any
strike or labor disturbance, accident, explosion, fire, storm, earthquake,
flood, epidemic or any other circumstance or event beyond the reasonable control
of the party relying upon such circumstance or event.



                                   ARTICLE 12

                               DISPUTE RESOLUTION


     Resolution of any and all disputes arising from or in connection with this
Agreement shall be exclusively governed by and settled in accordance with the
provisions of this ARTICLE 12.


     12.1 NEGOTIATION. The parties shall make a good faith attempt to resolve
any dispute arising out of or relating to this Agreement through negotiation
between appropriate representatives from each of Tekelec and Catapult. If at any
time after 30 days from the commencement of such communications either party
feels that such negotiations (or lack thereof if one party refuses to negotiate)
are not leading to a reasonably satisfactory resolution of the dispute, such
party may send a notice to the other party (in accordance with the notice
provisions set forth in SECTION 13.4 hereof) describing the dispute and
requesting a meeting of senior executives from each party. Within ten business
days after any such notice of a dispute is given, each party shall select one
executive officer


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of such party who shall have the authority to resolve the matter on behalf of
such party. Such designees shall then meet (in person or telephonically) to
attempt in good faith to negotiate a resolution of the dispute prior to pursuing
other available remedies. During the course of negotiations under this SECTION
12.1, all reasonable requests made by one party to the other for information,
including requests for copies of relevant documents, will be honored to the
extent reasonably possible. The specific format for such negotiations will be
left to the discretion of the designated negotiating senior executives but may
include the preparation of agreed upon statements of fact or written statements
of position furnished to the other party. In the event that any dispute arising
out of or related to this Agreement is not settled by the parties within 30 days
after the first meeting of the senior executives, either party may commence an
arbitration proceeding as described in Section 10.10 of the Asset Purchase
Agreement with respect to the dispute. Neither party shall invoke such
arbitration provisions against the other party to resolve a dispute until such
party has tried diligently and in good faith to settle the dispute through
communications with the other party during a period of at least 30 days after
the first meeting of the senior executives.


     12.2 PROCEEDINGS. Notwithstanding SECTION 12.1, no dispute regarding the
following is required to be negotiated prior to seeking relief from a court of
competent jurisdiction: breach of any obligation of confidentiality;
infringement, misappropriation, or misuse of any intellectual property right; or
any other claim where interim relief from the court is sought to prevent serious
and irreparable injury to a party. However, the parties shall make a good faith
effort to negotiate such dispute, in accordance with SECTION 12.1, while such
court action is pending.


     12.3 PAY AND DISPUTE. Except as provided herein, in the event of any
dispute regarding which party is responsible for payment of a third-party
invoice (subject to standard verification of receipt of products or services)
relating to Services provided hereunder or under any Transition Service
Schedule, the party named in such invoice must make timely payment to such third
party, even if the party named in the invoice desires to pursue the dispute
resolution procedures outlined in this ARTICLE 12. If the party that paid the
invoice is found pursuant to this ARTICLE 12 to not be responsible for such
payment, such paying party shall be entitled to reimbursement, with interest
accrued at a compounded annual rate of the Prime Rate plus 2%, from the party
found responsible for such payment. Such reimbursement shall be paid within 15
days after the parties agree or it is otherwise determined under this ARTICLE 12
that reimbursement is appropriate.


     12.4 CONTINUITY OF SERVICE AND PERFORMANCE. Unless otherwise agreed in
writing, the parties will continue to provide service and honor all other
obligations under this Agreement during the course of dispute resolution
pursuant to the provisions of this ARTICLE 12 with respect to all matters not
subject to such dispute, controversy or claim.



                                   ARTICLE 13

                                 MISCELLANEOUS


13.1 LIMITATION OF LIABILITY.


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             (a) SUBJECT TO SECTION 13.1(B) BELOW, IN NO EVENT SHALL EITHER
PARTY OR ITS SUBSIDIARIES OR OTHER AFFILIATES BE LIABLE TO THE OTHER PARTY OR
ITS SUBSIDIARIES OR OTHER AFFILIATES FOR ANY SPECIAL, CONSEQUENTIAL, INDIRECT,
INCIDENTAL OR PUNITIVE DAMAGES OR LOST PROFITS, HOWEVER CAUSED AND ON ANY THEORY
OF LIABILITY (INCLUDING NEGLIGENCE) ARISING IN ANY WAY OUT OF THIS AGREEMENT,
WHETHER OR NOT SUCH PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES
(COLLECTIVELY, "CONSEQUENTIAL DAMAGES").


             (b) IN THE EVENT THAT DURING THE SIX-MONTH PERIOD FOLLOWING THE
CLOSING DATE, Tekelec, INTENDING TO CAUSE SERIOUS AND MATERIAL INJURY TO
CATAPULT, BREACHES THIS AGREEMENT IN THE PERFORMANCE OF SERVICES UNDER
TRANSITION SERVICE SCHEDULE NO. 1 HERETO, THE LIMITATION ON CONSEQUENTIAL
DAMAGES SET FORTH IN SECTION 13.1(A) ABOVE SHALL NOT APPLY TO ANY CONSEQUENTIAL
DAMAGES RESULTING FROM SUCH BREACH, PROVIDED CATAPULT ASSERTS ITS CLAIM FOR SUCH
CONSEQUENTIAL DAMAGES IN WRITING NO LATER THAN 30 DAYS AFTER THE BREACH OCCURS
or is first discovered AND THAT NO CLAIMS MAY BE ASSERTED MORE THAN 30 DAYS
AFTER THE END OF SUCH SIX-MONTH PERIOD; PROVIDED, HOWEVER, THAT TEKELEC'S
MAXIMUM AGGREGATE LIABILITY FOR ANY SUCH CONSEQUENTIAL DAMAGES RESULTING FROM
BREACHES OCCURRING DURING SUCH SIX-MONTH PERIOD SHALL BE $5,000,000.


             (c) ALL LIABILITY OF TEKELEC FOR CONSEQUENTIAL DAMAGES UNDER
SECTION 13.1(B) SHALL BE DEEMED TO BE, AND SHALL BE INCLUDED WITHIN, LOSSES OF
TEKELEC FOR PURPOSES OF Article 8 OF THE PURCHASE AGREEMENT AND, WITHOUT
LIMITING THE GENERALITY OF THE FOREGOING, SUCH DAMAGES SHALL BE SUBJECT TO THE
LIMITATION ON RECOVERY TO AMOUNTS IN EXCESS OF THE BASKET AMOUNT AND SHALL BE
INCLUDED WITHIN TEKELEC'S LOSSES FOR PURPOSES OF DETERMINING TEKELEC'S
$18,000,000 AND $60,000,000 MAXIMUM AGGREGATE LIABILITY UNDER SECTION 8.6(a) OF
THE PURCHASE AGREEMENT.


     13.2 ENTIRE AGREEMENT. This Agreement and the Asset Purchase Agreement and
the Exhibits and Schedules referenced or attached hereto or thereto constitute
the entire agreement between the parties with respect to the subject matter
hereof and thereof and supersede all prior written and oral and all
contemporaneous oral agreements and understandings with respect to the subject
matter hereof and thereof.


     13.3 GOVERNING LAW. This Agreement shall be construed in accordance with
and all disputes hereunder shall be governed by the laws of the State of
California, excluding its conflict of law rules and the United Nations
Convention on Contracts for the International Sale of Goods. All claims brought
by Catapult are required to be brought and maintained in the Superior Court of
Los


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Angeles County or in the federal court for the Central District of California,
and all claims brought by Tekelec are required to be brought and maintained in
the Superior Court of Santa Clara County or in the federal court for the
Northern District of California, San Jose Division. Any and all counterclaims in
any action must be brought in the same court in which the related proceeding was
initiated in accordance with the foregoing provisions. The parties agree that
such courts shall have exclusive jurisdiction and venue over all disputes
between the parties that are permitted to be brought in a court of law pursuant
to SECTION 12.2 above.


     13.4 NOTICES. Any notice, demand, offer, request or other communication
required or permitted to be given by either party pursuant to the terms of this
Agreement shall be in writing and shall be deemed effectively given (i) if
delivered personally, on the date of such delivery, (ii) one Business Day after
being delivered by facsimile (with receipt of appropriate confirmation), (iii)
one Business Day after being deposited with a nationally recognized overnight
courier service, charges prepaid, or (iv) four days after being deposited in the
U.S. mail, First Class, with postage prepaid, in each case addressed to the
attention of the parties as follows:

         If to Tekelec:
         --------------

                           Tekelec
                           26580 W. Agoura Road
                           Calabasas, CA 91302
                           Attn:  Vice President and General Counsel
                           Fax:  (818) 880-0176

         with a copy to (which shall not constitute notice):

                           Bryan Cave LLP
                           120 Broadway, Suite 300
                           Santa Monica, CA 90401
                           Attn:  Katherine F. Ashton, Esq.
                           Fax:  (310) 576-2200

         If to Catapult:
         --------------

                           Catapult Communications Corporation
                           160 South Whisman Road
                           Mountain View, CA 94041
                           Attn:  Chief Operating Officer
                           Fax:  (650) 960-1029

         with a copy to (which shall not constitute notice):

                           Wilson Sonsini Goodrich & Rosati, P.C.
                           650 Page Mill Road

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                           Palo Alto, CA 94304
                           Attn:  Henry P. Massey, Jr., Esq.
                           Fax:  (650) 493-6811

     Tekelec and Catapult may substitute a different address or facsimile
number, from time to time, if such substitute is provided to the intended notice
recipient in writing by notice given in the manner provided in this SECTION
13.4.


     13.5 COUNTERPARTS. This Agreement, including the Schedules and any Exhibits
hereto and the other documents referred to herein, may be executed in
counterparts via facsimile or otherwise, each of which shall be deemed to be an
original but all of which shall constitute one and the same agreement.


     13.6 BINDING EFFECT; NONASSIGNABILITY. This Agreement shall inure to the
benefit of and be binding upon the parties hereto and their respective legal
representatives and successors, and nothing in this Agreement, express or
implied, is intended to confer upon any other Person any rights or remedies of
any nature whatsoever under or by reason of this Agreement. Except as herein
specifically provided to the contrary, neither party may assign this Agreement
or any rights or obligations hereunder, without the prior written consent of the
other party, and any such assignment shall be void; provided, however, that
either party (or its permitted successive assignees or transferees hereunder)
may assign or transfer this Agreement as a whole without consent to an entity
that succeeds to all or substantially all of the business or assets of such
party to which this Agreement relates.


     13.7 SEVERABILITY. The parties hereto have negotiated and prepared the
terms of this Agreement in good faith with the intent that each and every one of
the terms, covenants and conditions herein be binding upon and inure to the
benefit of the respective parties. Accordingly, if any one or more of the terms,
provisions, promises, covenants or conditions of this Agreement or the
application thereof to any person or circumstance shall be adjudged to any
extent invalid, unenforceable, void or voidable for any reason whatsoever by a
court of competent jurisdiction, such provision shall be as narrowly construed
as possible or, if necessary, deleted herefrom, and each and all of the
remaining terms, provisions, promises, covenants and conditions of this
Agreement or their application to other persons or circumstances shall not be
affected thereby and shall be valid and enforceable to the fullest extent
permitted by law. To the extent this Agreement is in violation of applicable
law, then the parties agree to negotiate in good faith to amend the Agreement,
to the extent possible consistent with its purposes, to conform to law.


     13.8 WAIVER OF BREACH. The waiver by either party hereto of a breach or
violation of any provision of this Agreement shall not operate as, or be
construed to constitute, a waiver of any subsequent breach of the same or
another provision hereof.


     13.9 AMENDMENT AND EXECUTION. This Agreement and amendments hereto shall be
in writing and executed in multiple copies via facsimile or otherwise on behalf
of Tekelec and Catapult


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by their respective duly authorized officers and representatives. Each multiple
copy shall be deemed an original, but all multiple copies together shall
constitute one and the same instrument.


     13.10 AUTHORITY. Each of the parties hereto represents to the other that
(a) it has the corporate or other requisite power and authority to execute,
deliver and perform this Agreement, (b) the execution, delivery and performance
of this Agreement by it have been duly authorized by all necessary corporate or
other actions, (c) it has duly and validly executed and delivered this
Agreement, and (d) this Agreement is a legal, valid and binding obligation,
enforceable against it in accordance with its terms subject to applicable
bankruptcy, insolvency, reorganization, moratorium or other similar laws
affecting creditors' rights generally and general equity principles.


     13.11 DESCRIPTIVE HEADINGS. The headings contained in this Agreement or in
any Exhibit or Schedule hereto are for reference purposes only and shall not
affect in any way the meaning or interpretation of this Agreement. Any
capitalized term used in any Schedule or Exhibit but not otherwise defined
therein, shall have the meaning assigned to such term in this Agreement. When a
reference is made in this Agreement to an Article or a Section, Exhibit or
Schedule, such reference shall be to an Article or Section of, or an Exhibit or
Schedule to, this Agreement unless otherwise indicated.


     13.12 GENDER AND NUMBER. Whenever the context of this Agreement requires,
the gender of all words herein shall include the masculine, feminine and neuter,
and the number of all words herein shall include the singular and plural.


     13.13 ADDITIONAL ASSURANCES. Except as may be specifically provided herein
to the contrary, the provisions of this Agreement shall be self-operative and
shall not require further agreement by the parties; PROVIDED, HOWEVER, that at
the request of either party, the other party shall execute such additional
instruments and take such additional acts as are reasonably necessary to
effectuate this Agreement; and PROVIDED FURTHER, that unless otherwise expressly
agreed by the parties or expressly provided for above, or in a Transition
Service Schedule, the requesting party shall bear all costs and expenses
associated with any such additional instruments and acts. The additional acts
required to be taken as provided in this SECTION 13.13 shall not include the
performance of any additional services that are not expressly included herein.


     13.14 NON-OCCURRENCE OF CLOSING. In the event that the Closing does not
occur on or before October 31, 2002, and unless the parties otherwise
specifically agree in writing, or in the event the Asset Purchase Agreement is
terminated in accordance with ARTICLE 9 thereof, this Agreement shall
automatically terminate as of such date or as of the date of such termination
and shall be of no further force and effect. Neither party will thereafter have
any liability or obligation to the other party hereunder or as a result of such
termination.


     13.15 SPECIFIC PERFORMANCE. The parties agree that irreparable damage would
occur in the event that any of the provisions of this Agreement were not
performed in accordance with their specific terms or were otherwise breached. It
is accordingly agreed that either party shall be entitled to seek an injunction
or injunctions or other equitable relief to prevent breaches of this Agreement


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and to enforce specifically the terms and provisions hereof in any court of the
United States or any state having jurisdiction over the dispute.


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     IN WITNESS WHEREOF, each of the parties has caused this Agreement to be
executed in duplicate originals by its duly authorized representatives.


                                   CATAPULT COMMUNICATIONS CORPORATION

                                   By:    /s/ Richard A. Karp
                                   Name:  Richard A. Karp
                                   Title: President and Chief Executive Officer


                                   TEKELEC

                                   By:    /s/ Frederick M. Lax
                                   Name:  Frederick M. Lax
                                   Title: Executive Vice President, Chief
                                          Operating Officer

                                   By:    /s/ Danny L. Parker
                                   Name:  Danny L. Parker
                                   Title: Vice President, Corporate Development`