<PAGE>


                                                                     EXHIBIT 4.7


                             STOCK PLEDGE AGREEMENT


This PLEDGE AGREEMENT, dated as of September 27, 2001, between INTEGRATED
SECURITY SYSTEMS, INC., a Delaware corporation ("Pledgor"), FROST NATIONAL BANK,
CUSTODIAN ("Custodian"), FBO RENAISSANCE US GROWTH & INCOME TRUST PLC, a public
limited company registered in England and Wales ("RUSGIT"), FROST NATIONAL BANK,
CUSTODIAN, FBO RENAISSANCE CAPITAL GROWTH & INCOME FUND III, INC., a Texas
corporation ("Renaissance III") ("RUSGIT and Renaissance III collectively
referred to as "Secured Party"), AND RENAISSANCE CAPITAL GROUP, INC., a Texas
corporation, as Agent for the Lender (the "Agent").

                                    RECITALS

         A. Secured Party has lent to Pledgor the aggregate principal amount of
One Hundred Fifty Thousand Dollars ($150,000) evidenced by the Pledgor's
promissory notes of even date herewith (the "Notes").

         B. Pledgor is the owner of the shares of capital stock issued by each
subsidiary ("Subsidiary") named on Schedule A, and Pledgor has agreed to pledge
and assign to Secured Party a security interest in such shares, together with
any additional shares of capital stock of a Subsidiary or of any subsidiary of
Pledgor subsequently issued or acquired by Pledgor (collectively, the "Shares"),
to secure payment of the Notes of Pledgor and all other indebtedness of Pledgor
to Secured Party (collectively, the "Obligations").

         NOW, THEREFORE, in consideration of the foregoing recitals and the
mutual covenants, the parties agree as follows:

         1. Pledge of Shares. Pledgor hereby pledges and assigns to the Secured
Party the Shares for the purpose of securing the full and prompt payment, when
due, by Pledgor of the Obligations.

         2. Delivery of Shares. Upon execution of this Pledge, Pledgor shall
deliver to the Custodian all the certificates representing the Shares, together
with duly executed stock powers, in blank. Custodian shall hold all such
certificates and stock powers subject to the terms of this Pledge Agreement.

         3. Voting of Shares and Receipt of Dividends. Pledgor shall have the
right to vote the Shares and to receive dividends and distributions on the
shares, except upon the occurrence of a default in the full and prompt payment
of the Obligations, when due (a "Default"), in which event Secured Party shall
have such rights.

         4. Representations and Warranties. Pledgor hereby warrants, represents
and covenants as follows:


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            a. Pledgor owns the Shares, free from any pledges, security
interests, adverse claims or liens;

            b. Pledgor will notify Secured Party of, and will defend the Shares
against, all claims and demands of all persons at any time claiming the Shares
or any interest therein;

            c. Pledgor will pay all taxes and assessments upon the Shares prior
to the date of delinquency for payment of such taxes and assessments;

            d. Pledgor has the full power, authority and capacity to grant the
security interest hereunder; and

            e. The Subsidiaries are the only operating subsidiaries of the
Pledgor, and the number of shares set forth on Schedule A constitute all of the
outstanding capital stock of the Subsidiaries.

         5. Return of Security. When the Obligations have been paid in full,
Agent shall promptly deliver the certificates representing the Shares then held
by it and all related stock powers to Pledgor.

         6. Occurrence of a Default. If a Default occurs, Agent or Secured Party
shall have the right to exercise any rights and remedies provided under the
Uniform Commercial Code of Texas or any other applicable law with respect to the
Shares.

         7. Duration of Pledge. This Pledge shall be terminated upon the earlier
of: (i) foreclosure by Secured Party of the security interest granted hereunder
upon the occurrence of a Default, or (ii) return of the Shares to Pledgor upon
payment of the Obligations.

         8. Miscellaneous.

            a. Governing Law. This Pledge shall be governed by and construed and
enforced in accordance with the substantive laws of the State of Texas, without
regard to the conflicts of laws provisions thereof, and the applicable laws of
the United States. Venue and jurisdiction shall be in the state or federal
courts in Dallas County, Texas.

            b. Binding Effect. All of the terms, covenants, representations,
warranties and conditions herein shall be binding upon, and inure to the benefit
of, and be enforceable by the parties and their respective successors and
assignees.

            c. Waiver. This Pledge may not be amended, modified, superseded or
canceled, nor may any of the terms, covenants, representations, warranties or
conditions hereof be waived, except by a written instrument executed by the
party against whom such amendment, modification, supersedure, cancellation or
waiver is charged. The failure of any party at any time or times to require
performance of any provision hereof shall in no manner affect the right at a
later time to enforce the same. No waiver by any party of any condition, or of
any breach of any term, covenant, representation or warranty contained herein,
in any one or more instances, shall


                                  Page 2 of 7
<PAGE>


be deemed to be or construed as a further or continuing waiver of any such
condition or breach or waiver of any other condition or of any breach of any
other term, covenant, representation or warranty.

            d. Attorneys' Fees. If any party brings an action in connection with
the performance, breach or interpretation of this Pledge, or in any action
related to the transaction contemplated hereby, the prevailing party in such
action shall be entitled to recover from the losing party in such action all
reasonable costs and expenses of such litigation, including attorneys' fees,
court costs, costs of investigation, accounting and other costs reasonably
incurred or related to such litigation.

            e. Severability. If any provision hereof is determined to be illegal
or unenforceable, such determination shall not affect the validity or
enforceability of the remaining provisions hereof, all of which shall remain in
full force and effect.

            f. Further Documents. Each party covenants and agrees that, from
time to time, after the date hereof, at the reasonable request of any other
party, and without further consideration, such party will execute and deliver
such other documents and take such other action reasonably required to carry
out, in all respects, the transactions contemplated and intended by this Pledge.

            g. Notices. Any notices or other communications required or
permitted to be given by this Agreement or any other documents and instruments
referred to herein must be (i) given in writing and personally delivered, mailed
by prepaid certified or registered mail or sent by overnight service, such as
FedEx, or (ii) made by telex or facsimile transmission delivered or transmitted
to the party to whom such notice or communication is directed, with confirmation
thereupon given in writing and personally delivered or mailed by prepaid
certified or registered mail.

         If to Pledgor:


                  Integrated Security Systems, Inc.
                  8200 Springwood Drive, Suite 230
                  Irving, Texas  75063
                  Telephone:  (972) 444-8280
                  Facsimile:  (972) 869-3843

                  with a copy to:

                  David H. Oden, Esq.
                  Haynes and Boone, LLP
                  1600 N. Collins, Suite 2000
                  Richardson, TX 75080
                  Telephone:  (972) 680-7550
                  Facsimile:  (972) 680-7551



                                  Page 3 of 7
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                  If to Secured Party:

                  Renaissance US Growth & Income Trust PLC
                  c/o Renaissance Capital Group, Inc.
                  8080 North Central Expressway, Suite 210-LB59
                  Dallas, Texas 75206
                  Attn.:   Russell Cleveland
                           President and Chief Executive Officer
                  Telephone:        (214) 891-8294
                  Facsimile:        (214) 891-8291

                  Renaissance Capital Growth & Income Fund III, Inc.
                  c/o Renaissance Capital Group, Inc.
                  8080 North Central Expressway, Suite 210-LB59
                  Dallas, Texas 75206
                  Attn.:   Russell Cleveland
                           President and Chief Executive Officer
                  Telephone:        (214) 891-8294
                  Facsimile:        (214) 891-8291

                  with a copy to:

                  Norman R. Miller, Esq.
                  Kirkpatrick & Lockhart LLP
                  1717 Main Street, Suite 3100
                  Dallas, Texas 75201
                  Telephone:        (214) 939-4906
                  Facsimile:        (214) 939-4949

                  If to Agent:

                  Renaissance Capital Group, Inc.
                  8080 North Central Expressway, Suite 210-LB59
                  Dallas, Texas 75206
                  Attn.:   Russell Cleveland
                           President and Chief Executive Officer
                  Telephone:        (214) 891-8294
                  Facsimile:        (214) 891-8291

                  with a copy to:

                  Norman R. Miller, Esq.
                  Kirkpatrick & Lockhart LLP
                  1717 Main Street, Suite 3100
                  Dallas, Texas 75201
                  Telephone:        (214) 939-4906
                  Facsimile:        (214) 939-4949


                                  Page 4 of 7
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         Any notice delivered personally in the manner provided herein will be
deemed given to the party to whom it is directed upon the party's (or its
agent's) actual receipt. Any notice addressed and mailed in the manner provided
herein will be deemed given to the party to whom it is addressed at the close of
business, local time of the recipient, on the fourth business day after the day
it is placed in the mail, or, if earlier, the time of actual receipt.

            h. Parties in Interest. Nothing in this Pledge, whether express or
implied, is intended to confer any rights or remedies under or by reason of this
Pledge on any persons other than the parties and their respective successors and
assigns, nor is anything in this Pledge intended to relieve or discharge the
obligation or liability of any third persons to any party to this Pledge, nor
shall any provision give any third persons any right of subrogation or action
over or against any party to this Pledge.

            i. Defined Terms. All capitalized terms, unless otherwise specified,
have the same meanings assigned to them in the Loan Agreement and Notes.

[The remainder of this page is intentionally left blank; signature page
follows.]


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         IN WITNESS WHEREOF, this Pledge Agreement is executed as of the date
first above written.

                                    PLEDGOR:

                                    INTEGRATED SECURITY SYSTEMS, INC.




                                    By:
                                        ----------------------------------------
                                        C. A. Rundell, Chairman and
                                        Chief Executive Officer

                                    SECURED PARTY:

                                    RENAISSANCE US GROWTH & INCOME TRUST PLC



                                    By:
                                        ----------------------------------------
                                        Russell Cleveland, Director


                                    RENAISSANCE CAPITAL GROWTH &
                                    INCOME FUND III, INC.

                                    By: Renaissance Capital Group, Inc.,
                                        Investment Adviser

                                        By:
                                            ------------------------------------
                                            Russell Cleveland, President and
                                            Chief Executive Officer


                                    AGENT:

                                    RENAISSANCE CAPITAL GROUP, INC.


                                    By:
                                        ----------------------------------------
                                        Russell Cleveland, President and
                                        Chief Executive Officer


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                                   SCHEDULE A



<Table>
<Caption>
                    SUBSIDIARIES                        NO. OF SHARES
                    ------------                        -------------
<S>                                                     <C>
           B&B Electromatic, Inc.                           1,000
           Intelli-Site, Inc.                               1,000
</Table>



                                  Page 7 of 7