<PAGE>
                                                                  EXHIBIT 10.25


                               SECURITY AGREEMENT

         This SECURITY AGREEMENT is made on this 8th day of January, 2002
between Radio Metrix Inc., a Florida corporation ("Debtor") and SDR METRO INC.
("Secured Party").

         WHEREAS, Secured Party and RadioMetrix Incorporated (i.e. - Radio
Metrix Inc., a Florida corporation), entered into a License Agreement as of the
14th day of March 1992, and an Amendment thereto dated by the parties on
February 14, 1997 and May 26, 1998 respectively (collectively hereinafter
referred to as the "License Agreement").

         WHEREAS, Secured Party, Brent Simon and Radio Metrix, Inc. (i.e. -
Radio Metrix Inc.) entered into a Purchase Agreement dated October 9, 2000 as
extended by that certain Extension Agreement entered into by and among the same
parties on September 25, 2001 pursuant to which the Secured Party and Brent
Simon agreed to sell to Radio Metrix Inc. U.S. Patent No. 5,337,039 ("Patent")
(collectively hereinafter referred to as the "Purchase Agreement"); and

         WHEREAS, Debtor and Secured Party, by this Security Agreement, wish to
set forth the terms and conditions pursuant to which Debtor grants to Secured
Party a security interest in the Patent.

         1.       SECURITY INTEREST. Debtor grants to Secured Party a security
interest in the Patent and the License Agreement attached as Exhibit "A" (the
"Collateral"). The security interest shall secure the payment and performance
of Debtor's Promissory Note of even date herewith in the principal amount of
Six Hundred Thousand ($600,000) Dollars ("Promissory Note").

         2.       COVENANTS.

                  (A)      Except as set forth in subparagraph (b) below, the
Debtor will not sell, dispose, or otherwise transfer the Collateral or any
interest therein without the prior written consent of Secured Party, and the
Debtor shall keep the Collateral free from unpaid charges.

                  (B)      Debtor shall have the absolute right, without
permission from or approval of Secured Party, to enter into licenses or
sublicenses regarding the Patent during the term of this Security Agreement and
to convey the Collateral as part of a merger or sale of assets, provided the
surviving party to the merger or the buyer expressly assumes all obligations
under the Promissory Note, this Security Agreement and the Remedy Upon Default
Agreement.

                  (C)      The Debtor shall execute alone or with Secured Party
any Financing Statement or other document or procure any document, and pay the
cost of filing the same in all public offices wherever filing is deemed by
Secured Party to be necessary.

         3.       TERM. This Agreement shall remain in force and effect until
the Promissory Note has been paid in full, and upon said payment, Secured Party
agrees that it will mark the Note cancelled, and return same to Debtor and
execute and file a Releasing Financing Statement.

         4.       DEFAULT. In the event of Default, the rights of the parties
shall be governed by the Remedy upon Default Agreement executed on even date by
the parties hereto and incorporated herein as Exhibit "B". Pursuant to the
Purchase Agreement, the Debtor shall be in default under this Agreement upon
the happening of noncompliance with or nonperformance of the Debtor's
obligations under the Note or this Agreement. This Agreement shall inure to the
benefit of and


<PAGE>


bind the heirs, executors, administrators, successors, and assigns of the
parties. This Agreement shall have the effect of an instrument under seal.

         IN WITNESS WHEREOF, the parties have signed this Agreement on the date
and year first above written.

Radio Metrix Inc.                          SDR Metro Inc.



By:   /s/ S. A. Michael, President        By:  /s/ David L. E. Jones, President
      -----------------------------            --------------------------------
      Stephen A. Michael
 As Its: President                         As Its: President


<PAGE>


                                                              US005337039A
<TABLE>
<S>                                                 <C>
United States Patent [19]                           [11] Patent Number:  5,337,039
Simon                                               [45] Date of Patent: Aug. 9, 1994
-----------------------------------------------------------------------------------------
[54] PROXIMITY DETECTION SYSTEM WITH                4,453,112  6/1984 Sauer............... 318/281
     DIGITAL FREQUENCY VARIATION                    4,652,864  3/1987 Calvin.............. 340/553
     DETECTION MEANS                                4,760,490  7/1988 Murao............... 361/181
                                                    4,794,273 12/1988 McCullough et al.... 307/139
[75] Inventor: Arvin B. Simon, Cleveland, Ohio      4,998,094  3/1991 Englmeier et al..... 340/572
[73] Assignee: SDR Metro Inc., Euclid, Ohio         5,034,722  7/1991 Premack............. 340/562

[21] Appl. No.: 915,097                             Primary Examiner -- Glen R. Swann, III
                                                    Attorney, Agent, or Firm -- Gifford, Groh, Sprinkle,
[22] Filed:   Jul. 16, 1992                         Patmore and Anderson

[51] Int. Cl.(3) .................... G08B 13/26    [57]                  ABSTRACT
[52] U.S. Cl. ................ 340/562; 307/116;
               331/65; 340/938; 340/939; 340/941    An oscillator which produces a continuous wave output
[58] Field of Search ........ 340/938, 939, 941,    signal on an antenna having a preset frequency. A de-
                   562, 340/561; 307/116; 331/65    tection circuit detects changes in the preset frequency
[56]          REFERENCES CITED                      resulting from proximity between the antenna and an
                                                    object and when such an object is detected, the detec-
           U.S. PATENT DOCUMENTS                    tion circuit generates an output signal. A compensation
3,346,856 10/1967 Dobble et al.......... 340/939    circuit is also provided for compensating for changes of
3,626,637 12/1971 Rudicel et al.                    the preset frequency which are caused by factors other
3,989,932 11/1976 Koerner............... 340/938    than proximity of the antenna with an object. Such
4,075,563  2/1978 Battle................ 340/939    other factors include radio frequency interference, long
4,103 252  7/1978 Bobick................ 331/48     term component degradation, temperature, and the like.
4,169,260  9/1979 Bayer................. 340/562
4,240,528 12/1980 Krans................. 187/52 R
4,345,167  8/1982 Calvin................ 307/308                  19 Claims, 2 Drawing Sheets
</TABLE>


                                   [GRAPHIC]


                                   EXHIBIT A



<PAGE>


                               License Agreement

         This LICENSE AGREEMENT (the "Agreement") is made and entered into by
and between Radio Metrix, Incorporated ("RMI"), a Florida corporation, and SDR
Metro, Incorporated ("SDRMI"), an Ohio corporation as of this 14th day of
March, 1992.

                                  WITNESSETH:

         WHEREAS, SDRMI has developed technology for a sensing device utilizing
radio waves in a unique fashion (Radio Proximity Sensing), more fully described
in Exhibit "A" (herein the "TECHNOLOGY"); and

         WHEREAS, RMI wishes to commercialize the TECHNOLOGY for all
applications; and

         WHEREAS, SDRMI wishes to grant RMI a license to the TECHNOLOGY
pursuant to the terms and conditions of this Agreement; and

         WHEREAS, the parties wish to enter into this Agreement setting forth
the terms and provisions of their understanding.

         NOW, THEREFORE, for good and valuable consideration, in hand received,
including the mutual covenants and promises of the parties as set forth in this
Agreement, the parties mutually agree as follows:

         1. LICENSE. SDRMI hereby grants RMI the exclusive, perpetual,
worldwide right to commercialize, manufacture, sell, market, apply, and utilize
the TECHNOLOGY for all applications. SDRMI shall not permit any other person or
entity to use or apply the TECHNOLOGY, or any part thereof, for any use without
the prior written permission of RMI, which may be withheld in the sole
discretion of RMI. Further, SDRMI agrees to assist in the defense of the
TECHNOLOGY from and against any use, infringement, or claim threatened or
asserted by any other party.

         RMI's license to the TECHNOLOGY for any specific application shall
become nonexclusive should RMI not commence sales of the TECHNOLOGY for that
specific application within 18 months after the date on which the final product
development has been completed and is available for commercial sale (the
"COMMERCIALIZATION PERIOD"). In such event, RMI's license to all other
applications of the TECHNOLOGY shall remain exclusive. The COMMERCIALIZATION
PERIOD will be extended for an additional six-month period upon good cause
being demonstrated. In the event that RMI's exclusivity for any specific
application is lost pursuant to the provisions of this paragraph, the royalty
responsibility of RMI to SDRMI for TECHNOLOGY used in that specific
application shall be equal to or better than the royalty arrangement or other
compensatory arrangement granted to any other party.

         2. COMMERCIALIZATION. RMI agrees to exercise its best efforts to
commercialize the TECHNOLOGY through commercial sales, sublicenses, joint
development agreements, and other commercialization efforts. RMI agrees to
immediately conduct a patentability search and providing that the TECHNOLOGY is
found to be patentable to promptly proceed with filing and prosecuting, at
RMI's sole cost, patent applications in the United States and in selected
international jurisdictions.


                                   EXHIBIT A



<PAGE>
Patent applications shall be jointly prepared by RMI and SDRMI, with SDRMI
working directly with the selected patent counsel. All patent applications
shall reflect Arvin Brent Simon as the sole inventor and SDRMI as the assignee.
SDRMI may assign its status as assignee to a corporation organized by SDRMI,
provided that said corporation becomes jointly bound under the terms of this
Agreement with SDRMI.

         3. ROYALTY. RMI agrees to pay SDRMI a royalty equal to forty percent
(40%) of all royalties received by RMI from the sale of products incorporating
the TECHNOLOGY or from the sale or use of the TECHNOLOGY. Once aggregate
royalty payments paid to SDRMI equal $75,000.00, all subsequent royalty
payments shall be reduced to twenty percent (20%) of all royalties received by
RMI from the sale of products incorporating the TECHNOLOGY or from the sale or
use of the TECHNOLOGY.

         In addition to the foregoing described royalty, an additional royalty
equaling ten percent (10%) (the "Volume Royalty") of all royalties received by
RMI from the sale of products incorporating TECHNOLOGY or from the use or sale
of the TECHNOLOGY to any single sublicensee of RMI which has sold a minimum of
200,000 units of a specific product incorporating the TECHNOLOGY in any
calendar year (the "Increase Royalty Level") shall be paid to SDRMI. The Volume
Royalty shall be computed each year for each sublicensee, with the sublicensee's
sales for each product starting at zero on January 1st of each year. The Volume
Royalties shall be paid commencing with the 200,001st unit of that product sold
by that specific sublicensee in each calendar year.

         Should RMI manufacture or market products incorporating the
TECHNOLOGY, RMI shall, in lieu of the foregoing royalty and Volume Royalty,
pay SDRMI a royalty equal to twenty-five percent (25%) of adjusted gross
revenues of RMI from such sales. "Adjusted Gross Revenues" shall mean gross
revenues from products manufactured or marketed by RMI, less only the cost of
materials, manufacturing costs, advertising costs, and sales costs paid to
parties who are not officers, directors, or stockholders of RMI or members of
their families. Reasonability of costs to be judged by generally accepted
accounting principals.

Should RMI grant a sublicense to any entity affiliated by stock ownership with
RMI, the royalty due and payable to SDRMI shall not be reduced as a result of
said sublicense arrangement from what the royalty would have been had the
manufacturing or sales been effected directly by RMI.

RMI shall pay all royalties on or before the 10th day of the month following
the receipt of said revenue by RMI. All royalty payments shall be accomplished
by a written report specifying revenues and the manner of calculation. SDRMI
shall have the right to inspect the books and records of RMI at any reasonable
time.

         4. SUBLICENSEE. Thirty percent (30%) of any sublicensee received by RMI
(excluding Development Payments and Advance Royalty Payments paid by any
sublicensee) shall be paid to SDRMI by the 10th day following the month of
receipt by RMI.

         Any sublicense proposed to be granted by RMI shall require the prior
approval of SDRMI, which shall not be unreasonably withheld. RMI shall give
SDRMI written notice of any proposed


                                      -2-

<PAGE>
sublicense arrangement, and SDRMI shall have 10 days to approve or reject the
sublicense as proposed. Rejection of a sublicense proposal by SDRMI shall be
made by written notification delivered to RMI within 10 days after said notice,
which written rejection shall specify the reason for said rejection. Failure of
SDRMI to object within said 10-day period shall constitute approval.

         Should SDRMI wish to obtain information or verification of sales by
any sublicensee, said request shall be made directly to RMI, and the inspection
request will be made under the contractual sublicense arrangement between RMI
and the sublicensee. In such event, SDRMI shall receive notice of the time and
place of said inspection and be permitted to have a representative present.

         5. DEVELOPMENT. RMI shall pay SDRMI $65.00 for each development hour
expended by SDRMI at the written request of RMI, together with a reimbursement
of the actual cost of development materials utilized. Any development funds
made available by any third party, including, but not limited to, sublicensees
("Development Funds"), shall be applied fifty percent (50%) for development
efforts by SDRMI and fifty percent (50%) for development-related and
commercialization activities by RMI, unless the allocation of the proceeds is
otherwise agreed upon by SDRMI and RMI, or unless the application of the
development funds are otherwise specified by the contributor of the funds.

         Any development effort by RMI shall be shared with SDRMI and shall be
deemed part of the TECHNOLOGY covered by this Agreement.

         Simultaneously with the execution of this Agreement, RMI shall pay
SDRMI an initial development payment of $12,500.00. In consideration for the
initial development payment, SDRMI shall deliver, on or before April 1, 1992,
to RMI a PC board and related materials constituting a working safety sensor,
manually adjustable and without CPU control (as yet to be developed)
incorporating the TECHNOLOGY for use on a parking boom, and a demonstration
prototype of a sensor device by April 3, 1992, incorporating the TECHNOLOGY for
use on an electric, overhead door. The parking boom shall be suitable for use
on parking booms manufactured by Magnetic Maulburg and the prototype for
overhead doors shall be suitable for use on overhead door openers manufactured
by manufacture(s) designated by RMI. The units shall, at the election of RMI,
either be delivered to the home offices of RMI, Sarasota, Florida, or shall be
available to be picked up by RMI at the home offices of SDRMI in Euclid, Ohio.

         6. REPRESENTATIONS AND WARRANTIES OF SDRMI. SDRMI makes the following
representations and warranties to RMI, each of which shall survive the closing:

                  (a)      SDRMI is the sole owner of the technology, subject
to no claims, interests, or rights of any third party.

                  (b)      SDRMI has full right and authority to enter into
this Agreement and to grant the license provided for herein.

                  (c)      SDRMI agrees to assist in the defense of the
TECHNOLOGY and any patents describing the TECHNOLOGY from any infringement upon
the rights of a third party or other patent and from any claim of any third
party.

                  (d)      The grant of the license and the license granted
herein do not require the approval


                                      -3-

<PAGE>

of any other party and do not violate or breach any agreement or obligation to
which SDRMI is party or to which the TECHNOLOGY is subject.

                  (e) Timothy McCullough has no right, claim, or interest in or
to the TECHNOLOGY, and SDRMI shall assist in the defense of the TECHNOLOGY and
RMI and its assigns from any claim or any right to compensation asserted by Mr.
McCullough or any other party. Should any compensation or other payment be due
Mr. McCullough as a result of the TECHNOLOGY, said payment and compensation
shall be the sole responsibility of SDRMI. Should no compensation be paid to
Mr. McCullough during any calendar year, the royalty fee due SDRMI shall be
reduced by 1.5% of RMI revenues; said reduction will only apply if RMI is
paying royalties to Robert Wilson.

                  (f) SDRMI shall not, during the term of this Agreement,
compete with the TECHNOLOGY in any application for which the TECHNOLOGY is
suitable. For purposes hereof, competition shall mean designing, developing,
marketing, commercializing, or manufacturing any product or any technology which
has a use or function similar to that served or which may be the TECHNOLOGY
(the "Competitive Activity") or serving as an officer, director, owner,
partner, shareholder, agent, or employee of any entity engaged in a Competitive
Activity.

                  (g) The TECHNOLOGY is proprietary and has not been disclosed
to any third party in a fashion which would adversely affect the confidentiality
or proprietary nature of the TECHNOLOGY.

                  (h) The TECHNOLOGY is patentable.

                  (i) Magnetic Maulburg has no right, title, or interest in or
to the TECHNOLOGY, and SDRMI agrees to assist RMI in defending any claim
asserted by Magnetic Maulburg to the TECHNOLOGY or any patent rights therein.

                  (j) SDRMI has no contractual or compensatory obligation to
Robert Wilson.

         7.       REPRESENTATIONS AND WARRANTIES OF RMI. RMI makes the following
representations and warranties to SDRMI, each of which shall survive the
closing:

                  (a) RMI has full right and authority to enter into this
Agreement.

                  (b) RMI will exercise its best efforts and good faith to
commercialize the TECHNOLOGY.

                  (c) RMI will exercise its best effort and good faith to
assist SDRMI in any way possible in developing the TECHNOLOGY for all
applications deemed appropriate.

                  (d) RMI shall not, during the term of this Agreement, compete
with the TECHNOLOGY in any application for which the TECHNOLOGY is suitable.
For purposes hereof, competition shall mean designing, developing, marketing,
commercializing, or manufacturing any product or any technology which has a use
or function similar to that served, or which may be served, by the TECHNOLOGY
(the "Competitive Activity") or serving as an officer, director, owner,
partner, shareholder, agent, or employee of any entity engaged in a Competitive
Activity.


                                      -4-


<PAGE>

                  (e) RMI shall grant Robert Wilson a royalty of up to five
percent of RMI'S net royalty interest in consideration for obtaining a general
release and shall exercise its best efforts to obtaining a general release and
shall exercise its best efforts to obtain from Mr. Wilson a general release in
favor of both SDRMI and RMI, a Confidentiality Agreement concerning the
TECHNOLOGY, and a Covenant not to Compete with the TECHNOLOGY executed by Mr.
Wilson.

         8.       NON-FRUSTRATION. Neither party to this Agreement shall commit
any act or take any action which frustrates or hampers the rights of the other
parties under this Agreement. Each party shall act in good faith and engage in
fair dealing when taking any action under or related to this Agreement.

         9.       ARBITRATION. Any dispute arising under this Agreement shall
be resolved solely by binding arbitration before the American Arbitration
Association. The party commencing the arbitration may select the location of
the arbitration hearing, which may be located in either Cleveland, Ohio, or
Sarasota, Florida. The finding of the arbitration panel shall be final and
binding and shall constitute the sole and exclusive means for resolving any
dispute under this Agreement. The determination of arbitrators may be reduced
to a final judgment in any court of competent jurisdiction.

         10.      MISCELLANEOUS. This agreement constitutes the entire
understanding of the parties and shall not be amended or otherwise altered,
except in writing, and executed by the parties hereto. This Agreement may not
be assigned by either party without the prior written approval of the other
party to this Agreement. This Agreement shall not be construed more stringently
against any party, regardless of who may have served as the draftsman. This
Agreement and the resolution of any dispute shall be governed by the laws of the
state Florida. This Agreement has been prepared by Samuel S. Duffey, as legal
counsel for RMI. SDRMI has been advised that Mr. Duffey is providing legal
services only to RMI and that SDRMI is entitled to consult with and rely upon
the advice of independent legal counsel.

         IN WITNESS WHEREOF, the parties have set their hand and seal on the
day and year first above written.

                                RMI
                                Radio Metrix, Incorporated



                                By:  /s/ Stephen Michael, 3-14-92
                                     ------------------------------------------
                                     STEPHEN MICHAEL, President


                                SDRMI
                                SDR Metro, Incorporated



                                By: /s/ David Lloyd E. Jones, President 3-14-92
                                    -------------------------------------------
                                    DAVID LLOYD E. JONES, President


                                      -5-

<PAGE>


                                    EXHIBIT A

                                       to

                               License Agreement
                                    Between
                                 SDRMI and RMI

Set forth below is a description of the TECHNOLOGY:

(5 hand written pages and 2 drawings attached as noted by signing parties)


                                                     /s/ S. A. Michael   3-14-92

                                                    /s/ D. L. E. Jones   3-14-92



                                      -6-
<PAGE>

                                                    Attach to License Agreement

                          FORM 10 - INDEX TO EXHIBITS
                          ITEM 10 - MATERIAL CONTRACT
                                FILING SCHEDULE

                               REDACTED MATERIAL

         The description of TECHNOLOGY is proprietary and contains
confidential/trade secret information and therefore is redacted, and not filed
herewith.

<PAGE>

                        AMENDMENT TO LICENSE AGREEMENT

         THIS AMENDMENT to License Agreement (the "Amendment") is made and
entered into by and between Radio Metrix, Incorporated ("RMI"), a Florida
corporation, and SDR Metro, Incorporated ("SDRMI"), an Ohio corporation as of
the day and year hereinafter written.

                                  WITNESSETH

         WHEREAS, RMI and SDRMI entered into a License Agreement dated March
14, 1992 (the "License Agreement"); and

         WHEREAS, RMI has selected a financial partner to further finance the
development, commercialization, manufacturing and marketing of various product
applications for the technology, as defined in the License Agreement
("TECHNOLOGY"); and

         WHEREAS, RMI and SDRMI wish to enter into this Addendum to: (i)
confirm that the License Agreement is in good standing and not subject to any
claims or acts of default and (ii) to alter the royalty payment requirements
under Paragraph 3 of the Agreement to accommodate concerns of RMI's financial
partner.

         NOW, THEREFORE, for good and valuable consideration, in hand received,
including but not limited to the mutual covenants and promises of the parties
as set forth in this Agreement, the parties mutually agree as follows:

         1.       The License Agreement is in good standing and is not subject
                  to any act or claim of default by either party.

         2.       RMI has completed product development of the application of
                  the TECHNOLOGY for parking barrier gates which constitutes
                  the only application for the TECHNOLOGY for which final
                  product development has been completed.

         3.       RMI commenced sales of products containing the TECHNOLOGY for
                  application on parking barrier gates within 18 months of the
                  final product development as required by the License
                  Agreement.

         4.       Mr. Carl Burnett, as a prior employee of RMI, invented a
                  proprietary noise-cancelling circuit which has applications
                  in conjunction with the TECHNOLOGY (the "Burnett Invention").
                  Mr. Burnett has assigned his invention to RMI.


===============================================================================
Amendment to License Agreement                                          Page 1


<PAGE>

                  RMI is in the process of filing a provisional or formal
                  Patent Application for the Burnett Invention, which
                  Patent(s), together with the proprietary circuitry, will be
                  owned exclusively by RMI. RMI confirms and agrees that no
                  royalty will be charged to SDRMI for any use of the Burnett
                  invention in connection with or in conjunction with the
                  TECHNOLOGY. SDRMI acknowledges that it has no interest in or
                  claim to the Burnett Invention.

         5.       The royalty payment requirements, as specified in Paragraph 3
                  of the License Agreement, are hereby amended and superseded
                  by the following:

                           "Should RMI manufacture or market products
                           incorporating the TECHNOLOGY, RMI shall in lieu of
                           the foregoing Royalty and Volume Royalty (and as the
                           only royalty due SDRMI for such sales) pay SDRMI a
                           royalty equal to the following declining percentage
                           of adjusted gross revenues:

                           25% of the adjusted gross revenues until aggregate
                           royalty paid to SDRMI in any calendar year are equal
                           to or less than $500,000.

                           20% of adjusted gross revenues until aggregate
                           royalty payments paid to SDRMI in any calendar year
                           are greater than $500,000 but less than $1,000,000.

                           15% of adjusted gross revenues once aggregate
                           royalty payments paid to SDRMI in any calendar year
                           exceed $1,000,000.

                           Royalties received by SDRMI shall mean the total of
                           royalties received from RMI and through RMI from any
                           sublicensee for each calendar year. The royalty
                           shall start over on January 1st of each year.


===============================================================================
Amendment to License Agreement                                          Page 2


<PAGE>

                           Adjusted gross revenues shall mean gross revenues
                           from products manufactured or marketed by RMI or any
                           sublicensee of RMI incorporating the TECHNOLOGY less
                           only the cost of materials, manufacturing costs,
                           advertising costs and sales costs paid to parties
                           who are not officers, directors or stockholders of
                           RMI or members of their families. Reasonability of
                           cost to be judged be generally accepted accounting
                           principals. It is intended by the parties that all
                           costs associated with manufacturing, marketing and
                           commercializing products incorporating the
                           TECHNOLOGY be deducted, including but not limited to
                           the costs of materials, sales, development,
                           warranty, advertising, promotional activities,
                           overhead and general administrative costs. Only
                           costs paid directly or indirectly to Stephen A.
                           Michael or Samuel S. Duffey or members of their
                           family, or costs which are not directly or
                           indirectly related to the TECHNOLOGY or products
                           incorporating the TECHNOLOGY shall not be a
                           deductible cost."

         6.       Any inconsistency between this Addendum and the License
                  Agreement shall be construed in favor of this Addendum. All
                  remaining terms and conditions of the License Agreement shall
                  remain in full force and effect.

         THIS ADDENDUM constitutes the entire understanding of the parties
concerning the subject matter hereof and shall not be amended or otherwise
altered except in writing executed by the parties hereto. This Addendum shall
not be construed more stringently against any party, regardless of who may have
served as the draftsman. This Addendum shall be governed by the laws of the
State of Florida. This Addendum has been prepared by Samuel S. Duffey, as legal
counsel for RMI and SDRMI has been advised that Mr. Duffey is providing legal
services only to RMI and that SDRMI is entitled to consult with and rely upon
the advice of independent legal counsel.


===============================================================================
Amendment to License Agreement                                          Page 3


<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Addendum as of the
day and year hereinafter written.


                                           RMI
                                           Radio Metrix, Incorporated



                                        By: /s/ Stephen A. Michael   14 Feb, 97
                                            -----------------------------------
                                           Stephen A. Michael, President  Date


                                           SDRMI
                                           SDR Metro, Incorporated



                                        By: /s/ David Lloyd E. Jones, President
                                                                        5/26/98
                                            -----------------------------------
                                           David Lloyd E. Jones, President Date



wpdata\radiomet\amend-li.agr


===============================================================================
Amendment to License Agreement                                          Page 4

<PAGE>

 Attach to Exhibit B - Remedy Upon Default Agreement under Security Agreement

                   FILING SCHEDULE PURSUANT TO PARAGRAPH 2.
   INSTRUCTIONS TO ITEM 601 UNDER SECTION 229.601 EXHIBITS OF REGULATION S-K

         Exhibit B - Remedy Upon Default Agreement is filed as the next
numbered Exhibit to this Index.