THIRD LEASE AMENDMENT

     THIS THIRD LEASE AMENDMENT (the "Amendment") is executed this ______ day of
December,  1997,  by and between  DUKE REALTY  LIMITED  PARTNERSHIP,  an Indiana
limited partnership  ('Landlord"),  and THRUCOMM,  INC., a(n) __________________
corporation f/k/a Dataline-I. Ltd. ("Tenant").

W I T N E S S E T H :

        WHEREAS,  Landlord's  predecessor in interest,  Industrial  Developments
International,  Inc.,  and Tenant  entered into a certain  lease dated April 15,
1991,  as amended  September  16, 1991 and January 31, 1994  (collectively,  the
"Lease"),  whereby Tenant leased from Landlord  certain  premises  consisting of
approximately  9,400 square feet of space (the "Original  Premises")  located in
Building D at 6900 Fairfield Business Drive, Fairfield, Ohio; and

        WHEREAS,  Landlord and Tenant desire to expand the Original  Premises by
approximately 4,700 square feet (the "Additional Space"); and

        WHEREAS, Landlord and Tenant desire to amend certain
provisions of the Lease to reflect such expansion;

        NOW, THEREFORE,  in consideration of the foregoing premises,  the mutual
covenants  herein  contained  and each act  performed  hereunder by the parties,
Landlord and Tenant hereby agree as follows:

        1.      Amendment of Article 1.

                Commencing  March 1, 1998,  Article 1, Items (b), (d), (e), (h),
(i) (j), and (n) of Article 1, Basic Lease  Provisions,  are hereby  deleted and
the following is substituted in lieu thereof:

        (b)     Demised Premises Square Footage:  14,100;

        (d)     Annual Minimum Rent:
                March 1, 1998 - January 31, 1999        $115,052.63 (11 months)
                February 1, 1999 - January 31, 2000     $125,511.96 per year
                February 1, 2000 - January 31, 2001     $125,511.96 per year
                February 1, 2001 - January 31, 2002     $125,511.96 per year
                February 1, 2002 - January 31, 2003     $125,511.96 per year
                February 1, 2003 - January 31, 2004     $125,511.96 per year
                February 1, 2004 - January 31, 2005     $125,511.96 per year;

        (e)     Monthly Rental Installments:

                Months 1-71             $10,459.33 per month;

        (h)     Termination Date:  January 31, 2005;

        (i)     Term:  Through January 31, 2005;

        (j)     Tenant's Operating Expense Percentage:  35.10%;
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       (n)     Addresses for payments and notices:

                Landlord:               Duke Realty Limited Partnership
                                        4555 Lake Forest Drive, Suite 400
                                        Cincinnati, OH  45242

                With Payments to:       Duke Realty Limited Partnership
                                        P.O. Box 960664
                                        Cincinnati, OH  45296-0664

                Tenant:                 ThruComm, Inc.
                                                Attn: Mark Gianinni
                                                1641 Commerce Avenue, N.
                                                St. Petersburg, FL  33716

        3. AMENDMENT OF ARTICLE 2.      Demised Premises.  Commencing
March 1, 1998, Article 2 of the Lease is hereby deleted and the
following is substituted in lieu thereof:

        "For and in  consideration  of the  rent  hereinafter  reserved  and the
mutual covenants  hereinafter  contained,  Landlord does hereby lease and demise
unto  Tenant,  and Tenant does hereby hire,  lease and accept from  Landlord the
following premises, referred to as the "Demised Premises":  approximately 14,100
square  feet of space  located  within  6900  Fairfield  Business  Drive  within
Fairfield  Business Center (the  "Project"),  located in Butler County,  Ohio as
shown on the floor plan attached hereto as Exhibit A-1 and incorporated  herein,
all upon the terms and conditions hereinafter set forth."

        4. INCORPORATION INTO ARTICLE 17.  Construction of Demised Premises. 
The following shall be added to Article 17 of the Lease:

        Tenant has  personally  inspected  the Demised  Premises and accepts the
same "as is" without representation or warranty by Landlord of any kind and with
the  understanding  that  Landlord  shall have no  responsibility  with  respect
thereto  except that  Landlord  agrees to perform and  complete  the work on the
tenant finish  improvements for the Additional Space as set forth in Exhibit B-1
attached  hereto  and  shall  give  Tenant  written  notice  of the day on which
Landlord  expects to  complete  such  work.  Landlord  agrees to pay  Thirty-one
Thousand Eight Hundred Thirty-eight Dollars and Ninety-four Cents  ($31,838.94)
toward  the cost of the tenant  finish  improvements  and  Tenant  agrees to pay
Thirty-one  Thousand Eight Hundred  Thirty-eight  Dollars and Ninety-four  Cents
($31,838.94) toward the cost of the tenant finish improvements. Tenant shall pay
Fifteen   Thousand  Nine  Hundred   Nineteen   Dollars  and  Forty-seven   Cents
($15,919.47)  of its  portion  upon  the  execution  of this  Amendment  and the
remaining amount on the date Landlord delivers the Additional Space to Tenant.

        Upon  completion  of the  work in the  Additional  Space,  Tenant  shall
execute a letter of understanding as referred to in Article 17 of the Lease.

        5. ADDITION OF ARTICLES 36 AND 37.  Articles 36 and 37 are hereby added
to the Lease:

        Article  36.  Financial  Statements.  During  the  Lease  Term  and  any
extensions thereof,  Tenant shall provide to Landlord on an annual basis, within
ninety (90) days  following the end of Tenant's  fiscal year, a copy of Tenant's
most recent certified and audited financial statements prepared as of the end of
Tenant's most recent fiscal year. Such financial statements shall be prepared in
conformity with generally accepted accounting principles, consistently applied.
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        Article 37.  Representations and  Indemnifications.  Any representations
and  indemnifications  of Landlord  contained  in the Lease shall not be binding
upon (i) any mortgagee having a mortgage  presently existing or hereafter placed
on the Building, or (ii) a successor to Landlord which has obtained or is in the
process  of  obtaining  fee  title  interest  to the  Building  as a result of a
foreclosure of any mortgage or a deed in lieu thereof.

        6. TENANT'S  REPRESENTATIONS AND WARRANTIES.  The undersigned represents
and warrants to Landlord that (i) Tenant is duly organized, validly existing and
in good  standing  in  accordance  with the laws of the state under which it was
organized;  (ii)  all  action  necessary  to  authorize  the  execution  of this
Amendment  has been  taken by Tenant;  and (iii) the  individual  executing  and
delivering  this Amendment on behalf of Tenant has been authorized to do so, and
such execution and delivery shall bind Tenant.  Tenant,  at Landlord's  request,
shall provide Landlord with evidence of such authority.

        7. EXAMINATION OF AMENDMENT.  Submission of this instrument for 
examination or signature to Tenant does not constitute a reservation or option,
and it is not effective until execution by and delivery to both Landlord and
Tenant.

        8. DEFINITIONS.  Except as otherwise provided herein, the capitalized 
terms used in this Amendment shall have the definitions set forth in the Lease.

        9. INCORPORATION.  This Amendment shall be incorporated into and made a
part of the Lease, and all provisions of the Lease not expressly modified or 
amended hereby shall remain in full force and effect.































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        IN WITNESS  WHEREOF,  the  parties  have  caused  this  Amendment  to be
executed on the day and year first written above.

        LANDLORD:

                                      DUKE REALTY LIMITED PARTNERSHIP,
WITNESSES:                            an Indiana limited partnership

__________________________
(Signature)
                                      By: Duke Realty Investments, Inc.,
__________________________                its general partner
(Printed)

__________________________            By: _________________________
(Signature)                               Robert D. Fessler
                                          Vice President and
__________________________                General Manager
(Printed)


        TENANT:

                                          THRUCOMM, INC., a(n)
                                       ----------------------------
WITNESSES:

__________________________             By: ___________________________
(Signature)                                 (Signature)

__________________________                 ____________________________
(Printed)                                   (Printed)

__________________________             Title: _________________________
(Signature)

__________________________
(Printed)



















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STATE OF _________________      )
                                ) SS:
COUNTY OF ________________      )

        Before me, a Notary Public in and for said County and State,  personally
appeared Robert D. Fessler, by me known and by me known to be the Vice President
and General Manager of Duke Realty  Investments,  Inc., an Indiana  corporation,
the  general  partner of Duke Realty  Limited  Partnership,  an Indiana  limited
partnership,  who  acknowledged  the  execution  of the  foregoing  "Third Lease
Amendment" on behalf of said partnership.

        WITNESS my hand and Notarial Seal this _____day of_______________, 1997.



                                             ---------------------------------
                                               Notary Public

                                             ---------------------------------
                                              (Printed Signature)

My Commission Expires:

My County of Residence:




STATE OF __________     )
                                ) SS:
COUNTY OF _________     )

        Before me, a Notary Public in and for said County and State,  personally
appeared  , by me known and by me known to be the  _________________________  of
ThruComm,  Inc., a(n)  ________________  who  acknowledged  the execution of the
foregoing "Third Lease Amendment" on behalf of said corporation.

        WITNESS my hand and Notarial Seal this _____day of _____________, 1997.


                                        _________________________________
                                                Notary Public

                                        _________________________________
                                                (Printed Signature)

My Commission Expires:

My County of Residence:








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