Exhibit 99.7

                                    GUARANTEE

         In consideration of, and in order to induce Alethea Limited
Partnership, a Delaware limited partnership (the "Lender") to enter into the
Line of Credit Agreement dated as of the date hereof (the "Line of Credit
Agreement") with Digilog, Inc. ("Digilog") and Numerex Corp. ("Guarantor"), and
to advance monies to Digilog in accordance with the terms thereof, the
Guarantor, being the parent of Digilog, guarantees the full and prompt payment
and performance of all of the obligations of Digilog to the Lender, whether
direct or indirect, absolute or contingent, due or to become due, now existing
or hereafter arising (the "Obligations"), which are incurred by Digilog pursuant
to (a) the Line of Credit Agreement, (b) the Term Promissory Note dated as of
the date hereof and issued by Digilog to the Lender pursuant to the Line of
Credit Agreement (the "Note"), and (c) the Security and Pledge Agreement dated
of the date hereof, among Digilog, the Guarantor and the Lender (the "Security
and Pledge Agreement"), or otherwise. This Guarantee is one of payment and not
of collectability. The liability of the Guarantor hereunder shall be unlimited
and shall continue, regardless of the payment, reduction, creation, or any
change in the amount of Obligations, and this Guarantee shall not be terminated
by the absence, from time to time, of indebtedness under the Line of Credit
Agreement or the Note being guaranteed hereby, but shall apply equally to all
new indebtedness thereafter created under the Line of Credit Agreement, the Note
or the Security and Pledge Agreement.

         The Guarantor waives presentment, protest, notice of acceptance of this
Guarantee, notice of any advances made, extensions granted, or other action
taken in reliance hereon and all demands and notices of every kind in connection
with this Guarantee or the Obligations hereby guaranteed; assents to any
renewal, extension or postponement of the time of payment or any other
indulgence, to any substitution, exchange or release of collateral, and/or to
the addition or release of any other person primarily or secondarily liable; and
it agrees to the provisions of the Line of Credit Agreement, the Note and/or
other paper evidencing the Obligations hereby guaranteed. The Guarantor waives
any claim or other right now existing or hereafter acquired against Digilog, or
any other party, that arises from the performance of Guarantor's obligations
under this Guarantee, including, without limitation, any right of reimbursement,
recourse, subrogation, indemnity, exoneration, as well as any rights or remedies
relating to any collateral security which the lender now has or hereafter may
acquire under the Security and Pledge Agreement or otherwise.

         It is agreed that the Lender may, upon any breach or default of Digilog
under the Line of Credit Agreement, the Note or the Security and Pledge
Agreement, or at any time thereafter, make demand upon the Guarantor, and
receive payment and performance of the Obligations, with or without notice or
demand for payment or performance on Digilog.



         This Guarantee shall inure to the benefit of the Lender and its
successors and assigns and shall be binding upon the Guarantor and the
successors and permitted assigns and/or other legal representatives of the
Guarantor.

         The Guarantor agrees to indemnify the Lender and hold it harmless from
and against all loss and expense, including legal fees, suffered or incurred by
the Lender as a result of claims to compel the return of any payment received by
the Lender from Digilog, or transfers for the Lender's account or collateral,
with respect to the Obligations of Digilog guaranteed herein. The Obligations of
Digilog guaranteed herein shall be automatically reinstated if and to the extent
the Lender is compelled to return any payment by or on behalf of Digilog, and
the Guarantor agrees to remain liable for such Obligations even though this
Guarantee may have been terminated and/or the agreements evidencing the debt
canceled, together with all costs, expenses and reasonable attorneys' fees
incurred in connection with the enforcement of this Guarantee.

         The Guarantor agrees to pay all of the Lender's costs and expenses,
including attorneys' fees and legal expenses incurred in connection with the
enforcement of this Guarantee. This Guarantee binds the undersigned by the sole
fact, that it bears the undersigned's signature. This Guarantee can be altered
only by a document or letter signed by the duly authorized representatives of
each of the Lender and the Guarantor. The Guarantor waives all rights to invoke
any condition, promise, or representation made by anyone which might have the
effect of invalidating this Guarantee or of limiting its interests.

         No failure or delay on the part of the Lender in exercising any right,
power, or privilege hereunder and no course of dealing between the Lender and
the Guarantor shall operate as a waiver of such right, power or privilege.

         The Obligations of the Guarantor under this Guarantee shall continue in
full force and effect until the payment, observance and performance in full of
the Obligations.

         This Guarantee and the rights and obligations of the Guarantor
hereunder shall be construed in accordance with the laws of the State of Florida
without giving effect to the conflict of laws rules. This Guarantee may be
signed in counterparts, each of which shall be deemed to be an original.

         Any judicial proceeding brought against the Guarantor with respect to
this Guarantee may be brought in the courts of the State of Florida, and by
execution and delivery of this Guarantee, the Guarantor (i) accepts, generally
and unconditionally, the nonexclusive jurisdiction of such courts and any
related appellate court, and irrevocably agrees to be bound by any judgment
rendered thereby in connection with this Guarantee and (ii) irrevocably waives
any objection it may now or hereafter have as to the venue of any such suit,
action or proceeding brought in such courts or that any such court is an
inconvenient forum. Nothing herein shall affect the right of the Lender to bring
proceedings against the Guarantor in the courts of any other jurisdiction. The
Guarantor hereby consents to service of process in any suit, action or other
proceeding arising out of the transactions contemplated hereby, and hereby
irrevocably appoints the Florida office of CT Corporation as its
attorney-in-fact for the purpose of receiving service of process in any action,
suit, or proceeding in any of such courts.



         THE GUARANTOR AND THE LENDER EACH HEREBY WAIVE, TO THE FULLEST EXTENT
PERMITTED BY LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY OF ANY DISPUTE
ARISING UNDER OR RELATING TO THIS GUARANTEE, AND EACH HEREBY AGREES THAT ANY
SUCH DISPUTE SHALL BE TRIED BEFORE A JUDGE SITTING WITHOUT A JURY.

         IN WITNESS WHEREOF, the Guarantor has caused this Guarantee to be
executed as of this ___ day of March, 2003.

                                    Guarantor:

                                    NUMEREX CORP.

                                    By: /s/ Michael Marrett
                                        ----------------------------------------
                                    Name:  Michael Marrett
                                    Title: Executive Vice President

STATE OF GEORGIA___________)
                           ) ss:
COUNTY OF FULTON___________)

On this ___ day of March, 2003, before me, ________________________, the
undersigned officer, personally appeared, ___________________________ who
acknowledged him/herself to be the _________________________ of Numerex Corp.,
and that he/she, being duly authorized so to do, executed the foregoing
instrument for the purposes therein contained, and who duly acknowledged the
execution of the same to be his/her free act and deed individually and as such
officer, and the free act and deed of said corporation for the purposes therein
contained, by signing the name of the corporation by him/herself as such
officer.

IN WITNESS WHEREOF, I hereunto set my hand.

                                       _____________________________________
                                                   Notary Public

My Commission Expires: ____________________