<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                   FORM 10-K/A

                               Amendment No. 1 to
                  Annual Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934
                   For the fiscal year ended December 31, 1996

                           COMMISSION FILE NO. 0-24303


                   COHERENT COMMUNICATIONS SYSTEMS CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

DELAWARE                                                           11-2162982
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)

                             44084 RIVERSIDE PARKWAY
                            LANSDOWNE BUSINESS CENTER
                            LEESBURG, VIRGINIA 22075
                                 (703) 729-6400

               (Address of principal executive offices) (Zip Code)
              (Registrant's telephone number, including area code)

Securities registered pursuant to section 12(b) of the Act:

Title of each class                                     Name of each exchange on
                                                                which registered

       None                                                  Not applicable

Securities registered pursuant to section 12(g) of the Act:

                     COMMON STOCK, PAR VALUE $.01 PER SHARE

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. [X]

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
495 of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment of this Form 10-K. [X]

     The aggregate market value of voting stock held by nonaffiliates of the
registrant as of March 13, 1997, was approximately $153,044,650 based on the
sale price of the Common Stock on March 13, 1997, of $16.75 as reported by the
NASDAQ National Market System. As of March 13, 1997, the registrant had
outstanding 15,146,522 shares of its Common Stock, par value $.01 per share.

DOCUMENTS INCORPORATED BY REFERENCE

     Portions of the Proxy Statement for the Annual Meeting of Stockholders to
be held on May 15, 1997 are incorporated herein by reference in Part III, Items
10, 11, 12 and 13.
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Coherent Communications Systems Corp.




                                     PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

         (a)  The following documents are filed as part of this Annual Report on
              Form 10-K:

         1.   Consolidated Financial Statements:

              The consolidated financial statements filed as a part of this
              report are listed in the "Index to Consolidated Financial
              Statements and Financial Statement Schedule" at Item 8.

         2.   Consolidated Financial Statement Schedule:

              The consolidated financial statement schedule filed as part of
              this report is listed in the "Index to Consolidated Financial
              Statements and Financial Statement Schedule" at Item 8.

              Schedules other than those listed on the accompanying Index to
              Consolidated Financial Statements and Financial Statement Schedule
              are omitted for the reason that they are either not required, not
              applicable, or the required information is included in the
              consolidated financial statements or notes thereto.

         (b)  REPORTS ON FORM 8-K     None.

         (c)  Exhibits:

              The following is a list of exhibits required by Item 601 of
              Regulation S-K filed as part of this report. Where so indicated by
              footnote, exhibits which were previously filed are incorporated by
              reference. Exhibits incorporated by reference, the location of the
              exhibit in the previous filing is indicated in parentheses. All
              other exhibits are being filed with this report.

<TABLE>
<CAPTION>
       Exhibit No.                           Description
       -----------                           -----------
<S>                   <C>
           3(i)   -   Certificate of Incorporation of the Company, as amended by
                      a Certificate of Amendment.(3) (Exhibit 3.1(i))

          3(ii)   -   By-laws of the Company as amended.(5)(Exhibit 3(ii))

            4.1   -   Specimen stock certificate representing the Common
                      Stock.(3)(Exhibit 4.1)

           10.1   -   Administrative Services Agreement dated as of December 1,
                      1993, between the Company and Safeguard Scientifics,
                      Inc.(3)(Exhibit 10.1)

           10.2   -   Asset Purchase Agreement dated as of March 18, 1987
                      between COMSAT Telesystems, Inc. and the
                      Company.(1)(Exhibit 10.2)

          *10.3   -   1982 Stock Option Plan.(1)(Exhibit 10.3)

          *10.4   -   1993 Equity Compensation Plan, as amended and restated.

        *10.4.1   -   Stock Ownership Plan(5)(Exhibit 10.4.1)

         10.4.2   -   Compensation Plan for Outside Directors

          *10.5   -   Form of Non-Qualified Stock Option Agreement of the
                      Company for Employees.(2)(Exhibit 10.5)

          *10.6   -   Form of Non-Qualified Stock Option Agreement of the
                      Company for Directors.(2)(Exhibit 10.6)

          *10.7   -   Form of Incentive Stock Option Agreement of the Company
                      for Employees.(2)(Exhibit 10.7)


           10.8   -   Lease dated as of February 1, 1980, as amended, between
                      LE-AX Corp. and the Company, for the property at 60
                      Commerce Drive, Hauppauge, New York.(1)(Exhibit 10.8)
</TABLE>




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<PAGE>   3
Coherent Communications Systems Corp.




ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

         (c)  Exhibits (continued):

         10.9.1   -   Lease dated as of July 31, 1992 between Linpro Lansdowne
                      Two Limited Partnership and the Company, for the property
                      at 44084 Riverside Parkway, Leesburg, Virginia.(1)(Exhibit
                      10.9.1)

         10.9.2   -   Sublease dated as of August 1993 between G.D. Searle & Co.
                      and the Company, for the property at 44084 Riverside
                      Parkway, Leesburg, Virginia.(1)(Exhibit 10.9.2)

         10.9.3   -   Lease dated August 9, 1996 by and between Opus East,,
                      L.L.C., Landlord, and the Company for the premises located
                      in Loudon County, Virginia known as University Center.

          10.10   -   Lease dated as of October 15, 1990 between Kibswell
                      Holdings Limited and the Company, for the property at Unit
                      B The Quadrant, Barton Lane, Abingdon,
                      England.(1)(Exchange 10.10)

          10.11   -   Tax Agreement dated January 1, 1983 between Safeguard
                      Scientifics, Inc. and the Company.(1)(Exhibit 10.11)

         *10.12   -   Severance and Non-Competition Agreement dated as of
                      February 10, 1994 between Daniel McGinnis and the
                      Company.(1)(Exhibit 10.12)

          10.13   -   Form of Demand Promissory Note of Safeguard Scientifics,
                      Inc., dated April 2, 1993, payable to the Company, as
                      amended by letter Agreement dated January 12,
                      1994.(1)(Exhibit 10.13)

          10.14   -   Form of Promissory Note of the Company payable to
                      Safeguard Scientifics, Inc. with respect to the redemption
                      of redeemable convertible preferred stock.(3)(Exhibit
                      10.14)

          10.15   -   Supply and License Agreement dated February 7, 1992,
                      between the Company and TRT Telecommunications
                      Radioelectriques et Telephoniques.(1)(Exhibit 10.15)

          10.16   -   International Distribution Agreement dated as of January
                      2, 1992 between the Company and Cohpac Communications
                      Systems Pty Limited.(1)(Exhibit 10.16)

          10.17   -   North America Value Added Reseller Agreement dated as of
                      December 7, 1992 between the Company and Wandel &
                      Goltermann Inc.(1)(Exhibit 10.17)

         *10.18   -   Management Incentive Compensation Plan, as adopted by the
                      Company.(2)(Exhibit 10.18)

          10.19   -   License Agreement, effective as of June 1, 1994, between
                      the Company and Systems Technology Associates, Inc.
                      (3)(Exhibit 10.19)

          10.20   -   Value Added Reseller Agreement dated December 31, 1992 as
                      amended June 13, 1995 between the Company and Nokia
                      Telecommunications Oy(5)(Exhibit 10.21)**

          10.21   -   Memorandum of Understanding dated February 27,1997 between
                      the Company and Nokia Telecommunications Oy**

           11.0   -   Computation of net income per share.




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<PAGE>   4
Coherent Communications Systems Corp.




ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

         (c)  Exhibits (continued):

           21.0   -   Subsidiaries of registrant.

           23.0   -   Consent of KPMG Peat Marwick LLP

           27.0   -   Financial Data Schedule.

----------------

(1) Filed on March 31, 1994 as an exhibit to the Company's Registration
    Statement on Form S-1 (No.33-77160) and incorporated by reference.

(2) Filed on May 24, 1994 as an exhibit to the Company's Registration Statement
    on Form S-1 Amendment #1 (No.33-77160) and incorporated by reference.

(3) Filed on June 10, 1994 as an exhibit to the Company's Registration Statement
    on Form S-1 Amendment #2 (No.33-77160) and incorporated by reference.

(4) Filed as an exhibit to the Company's Annual Report on Form 10-K for the year
    ended December 31, 1994 and incorporated by reference.

(5) Filed as an exhibit to the Company's Annual Report on Form 10-K for the year
    ended December 31, 1995 and incorporated by reference.

*   Management contract or compensatory plan or arrangement.

**  Confidential portions of the exhibit have been omitted and filed separately
    with the Securities and Exchange Commission pursuant to a request for
    confidential treatment.




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<PAGE>   5
Coherent Communications Systems Corp.




    SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this to be signed on its
behalf by the undersigned, thereunto duly authorized.


                                   COHERENT COMMUNICATIONS SYSTEMS CORPORATION


                                   By:    /s/ Melba G. Chan
                                      ----------------------------------------
                                              Melba G. Chan,
                                              Chief Financial Officer


                                   Date: October 15, 1997




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<PAGE>   6
Coherent Communications Systems Corp.




                                  EXHIBIT INDEX

The following is a list of exhibits required by Item 601 of Regulation S-K filed
as part of this Report. Where so indicated by footnote, exhibits which were
previously filed are incorporated by reference. For exhibits incorporated by
reference, the location of the exhibit in the previous filing is indicated in
parentheses. The page numbers listed refer to the page numbers where such
exhibits are located using the sequential numbering system specified by Rule
0-3.


<TABLE>
<CAPTION>
       Exhibit No.                           Description
       -----------                           -----------
<S>                   <C>
           3(i)   -   Certificate of Incorporation of the Company, as amended by
                      a Certificate of Amendment.(3) (Exhibit 3.1(i))

          3(ii)   -   By-laws of the Company as amended.

            4.1   -   Specimen stock certificate representing the Common
                      Stock.(3)(Exhibit 4.1)

           10.1   -   Administrative Services Agreement dated as of December 1,
                      1993, between the Company and Safeguard Scientifics,
                      Inc.(3)(Exhibit 10.1)

           10.2   -   Asset Purchase Agreement dated as of March 18, 1987
                      between COMSAT Telesystems, Inc. and the
                      Company.(1)(Exhibit 10.2)

          *10.3   -   1982 Stock Option Plan.(1)(Exhibit 10.3)

          *10.4   -   1993 Equity Compensation Plan, as amended and restated.

        *10.4.1   -   Stock Ownership Plan(5)(Exhibit 10.4.1)

         10.4.2   -   Compensation Plan for Outside Directors

          *10.5   -   Form of Non-Qualified Stock Option Agreement of the
                      Company for Employees.(2)(Exhibit 10.5)

          *10.6   -   Form of Non-Qualified Stock Option Agreement of the
                      Company for Directors.(2)(Exhibit 10.6)

          *10.7   -   Form of Incentive Stock Option Agreement of the Company
                      for Employees.(2)(Exhibit 10.7)

           10.8   -   Lease dated as of February 1, 1980, as amended, between
                      LE-AX Corp. and the Company, for the property at 60
                      Commerce Drive, Hauppauge, New York.(1)(Exhibit 10.8)

         10.9.1   -   Lease dated as of July 31, 1992 between Linpro Lansdowne
                      Two Limited Partnership and the Company, for the property
                      at 44084 Riverside Parkway, Leesburg, Virginia.(1)(Exhibit
                      10.9.1)

         10.9.2   -   Sublease dated as of August 1993 between G.D. Searle & Co.
                      and the Company, for the property at 44084 Riverside
                      Parkway, Leesburg, Virginia.(1)(Exhibit 10.9.2)

         10.9.3   -   Lease dated August 9, 1996 by and between Opus East,,
                      L.L.C., Landlord, and the Company, for the premises
                      located in Loudon County, Virginia known as University
                      Center.

          10.10   -   Lease dated as of October 15, 1990 between Kibswell
                      Holdings Limited and the Company, for the property at Unit
                      B The Quadrant, Barton Lane, Abingdon,
                      England.(1)(Exchange 10.10)

          10.11   -   Tax Agreement dated January 1, 1983 between Safeguard
                      Scientifics, Inc. and the Company.(1)(Exhibit 10.11)

         *10.12   -   Severance and Non-Competition Agreement dated as of
                      February 10, 1994 between Daniel McGinnis and the
                      Company.(1)(Exhibit 10.12)
</TABLE>




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<PAGE>   7
Coherent Communications Systems Corp.




          10.13   -   Form of Demand Promissory Note of Safeguard Scientifics,
                      Inc., dated April 2, 1993, payable to the Company, as
                      amended by letter Agreement dated January 12,
                      1994.(1)(Exhibit 10.13)

          10.14   -   Form of Promissory Note of the Company payable to
                      Safeguard Scientifics, Inc. with respect to the redemption
                      of redeemable convertible preferred stock.(3)(Exhibit
                      10.14)

          10.15   -   Supply and License Agreement dated February 7, 1992,
                      between the Company and TRT Telecommunications
                      Radioelectriques et Telephoniques.(1)(Exhibit 10.15)

          10.16   -   International Distribution Agreement dated as of January
                      2, 1992 between the Company and Cohpac Communications
                      Systems Pty Limited.(1)(Exhibit 10.16)

          10.17   -   North America Value Added Reseller Agreement dated as of
                      December 7, 1992 between the Company and Wandel &
                      Goltermann Inc.(1)(Exhibit 10.17)

         *10.18   -   Management Incentive Compensation Plan, as adopted by the
                      Company.(2)(Exhibit 10.18)

          10.19   -   License Agreement, effective as of June 1, 1994, between
                      the Company and Systems Technology Associates, Inc.
                      (3)(Exhibit 10.19)

          10.20   -   Value Added Reseller Agreement dated December 31, 1992 as
                      amended June 13, 1995 between the Company and Nokia
                      Telecommunications Oy (5)(Exhibit 10.21)**

          10.21   -   Memorandum of Understanding dated February 27,1997 between
                      the Company and Nokia Telecommunications Oy**

           11.0   -   Computation of net income per share.

           21.0   -   Subsidiaries of registrant.

           23.0   -   Consent of KPMG Peat Marwick LLP

           27.0   -   Financial Data Schedule

----------------

(1) Filed on March 31, 1994 as an exhibit to the Company's Registration
    Statement on Form S-1 (No.33-77160) and incorporated by reference.

(2) Filed on May 24, 1994 as an exhibit to the Company's Registration Statement
    on Form S-1 Amendment #1 (No.33-77160) and incorporated by reference.

(3) Filed on June 10, 1994 as an exhibit to the Company's Registration Statement
    on Form S-1 Amendment #2 (No.33-77160) and incorporated by reference.

(4) Filed as an exhibit to the Company's Annual Report on Form 10-K for the year
    ended December 31, 1994 and incorporated by reference.

(5) Filed as an exhibit to the Company's Annual Report on Form 10-K for the year
    ended December 31, 1995 and incorporated by reference.

*   Management contract or compensatory plan or arrangement.

**  Confidential portions of the exhibit have been omitted and filed separately
    with the Securities and Exchange Commission pursuant to a request for
    confidential treatment.




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