<PAGE>

  AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 30, 1997,
                             REGISTRATION NO.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                         ------------------------------
 
                                    FORM S-8
 
                             REGISTRATION STATEMENT
 
                                     UNDER
 
                           THE SECURITIES ACT OF 1933
                                ----------------
 
                              SYNC RESEARCH, INC.
             (Exact name of Registrant as specified in its charter)
 
<TABLE>
<S>                              <C>                            <C>
           DELAWARE                          3661                  33-0676350
 (State of other jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
incorporation or organization)                                      Number)
</TABLE>
 
                                  40 PARKER
                                IRVINE, CA 92618
                                 (714) 588-2070
         (Address, including zip code, and telephone number, including
            area code, of Registrant's principal executive offices)
 
            SYNC RESEARCH, INC. 1996 NON-EXECUTIVE STOCK OPTION PLAN
                            (Full title of the plan)
 
                         ------------------------------
 
                                ROGER A. DORF
                            CHIEF EXECUTIVE OFFICER
                              SYNC RESEARCH, INC.
                                   40 PARKER
                                IRVINE, CA 92618
                                 (714) 588-2070
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
 
                         ------------------------------
 
                                   COPIES TO:
                                MARK A. MEDEARIS
                               VENTURE LAW GROUP
                              2800 SAND HILL ROAD
                          MENLO PARK, CALIFORNIA 94025
                                 (415) 854-4488
 
                         ------------------------------
 
<PAGE>

                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<CAPTION>
                                                                         PROPOSED MAXIMUM   PROPOSED MAXIMUM
                  TITLE OF SECURITIES                     AMOUNT TO BE    OFFERING PRICE       AGGREGATE          AMOUNT OF
                    TO BE REGISTERED                       REGISTERED        PER SHARE       OFFERING PRICE    REGISTRATION FEE
<S>                                                       <C>            <C>                <C>                <C>
  SYNC RESEARCH INC. 1996 NON-EXECUTIVE STOCK OPTION PLAN
  Common Stock, $0.001 par value........................   756,155(1)        $3.8832          $2,936,301.10         $889.79(2) 

  Common Stock, $0.001 par value........................    70,417           $4.0313          $  283,872.05         $ 86.02(3) 
                                                           -------                            -------------         -------    
                                                           826,572(1)                         $3,220,173.15         $975.81(2) 
</TABLE>

(1) This total represents a 826,572 share increase in the shares reserved for 
    issuance under the 1996 Non-Executive Stock Option Plan (the "Plan"), 
    which increase was approved by the Registrant's Board of Directors at 
    meetings and by actions taken by unanimous written consent of the board 
    of directors on September 27, 1996, November 26, 1996, January 8, 1997, 
    January 14, 1997, January 29, 1997 and March 7, 1997. Of the 826,572 shares
    being registered hereunder, 756,155 shares are subject to outstanding 
    options and 70,417 are available for issuance.  An additional 350,500 
    shares were registered for issuance under the Plan pursuant to a previous 
    registration statement on Form S-8 filed by the Registrant, (registration 
    number 333-12315) with the Commission on September 19, 1996.

(2) Computed in accordance with Rule 457(h) under the Securities Act of 1933
    solely for the purpose of calculating the registration fee. Computation
    based on the weighted average per share exercise price (rounded to nearest
    cent) of outstanding options under the referenced plan, the shares issuable
    under which are registered hereby.

(3) Estimated in accordance with Rule 457(h) and 457(c) under the Securities 
    Act of 1933 solely for the purpose of calculating the registration fee. 
    The computation with respect to unissued options is based on the 
    average of the high and low sale prices of the Common Stock as reported on 
    The Nasdaq National Market on May 22, 1997.





<PAGE>
                                    PART II
 
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

        The contents of the Registrant's previous Registration Statement on 
    Form S-8 (No. 333-12315) pertaining to the Sync Research, Inc. 1996 
    Non-Executive Stock Option Plan are hereby incorporated by reference 
    herein.

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE
 
    The following documents and information heretofore filed with the Securities
and Exchange Commission are hereby incorporated by reference:
 
    ITEM 3 (A)

        The Registrant's Annual Report on Form 10-K for the year ended 
    December 31, 1996, filed on March 31, 1997, pursuant to Section 13 of the 
    Securities Exchange Act of 1934, as amended (the "Exchange Act"), which 
    contains audited financial statements for the Registrant's latest fiscal 
    year for which such statements have been filed.
 
    ITEM 3 (B)
 
        The Registrant's Quarterly Report on Form 10-Q for the quarter ended 
    March 31, 1997, filed on May 12, 1997 pursuant to Section 13 of the 
    Exchange Act.
 
    ITEM 3 (C)
 
        Items 1 and 2 of the Registrant's Registration Statement on Form 8-A
    filed on October 10, 1995, and Items 1 and 2 of the Registrant's
    Registration Statement on Form 8-A, filed on November 4, 1995, each pursuant
    to Section 12 of the Exchange Act.
 
    All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered have been
sold or which deregisters all securities then remaining unsold, shall be deemed
to be incorporated by reference in this Registration Statement and to be part
hereof from the date of filing of such documents.
 
ITEM 4.  DESCRIPTION OF SECURITIES
 
    Not Applicable.
 
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL
 
    Not Applicable.
 
ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Section 145 of the Delaware General Corporation Law authorizes a court to
award, or a corporation's Board of Directors to grant indemnity to directors and
officers in terms sufficiently broad to permit such indemnification under
certain circumstances for liabilities (including reimbursement for expenses
incurred) arising under the Securities Act of 1933, as amended (the "Act").
 
    Article X of the Registrant's Amended and Restated Certificate of
Incorporation, filed November 17, 1995, provides for indemnification of its
directors, officers and employees to the maximum extent permitted by the
Delaware General Corporation Law.
 
                                      II-1
<PAGE>
    Article VI of the Registrant's Bylaws provides that the Registrant shall
indemnify its directors and officers to the fullest extent permitted by Delaware
law against expenses, judgments and other amounts actually and reasonably
incurred in connection with a proceeding arising from the person's status as an
agent of the Corporation. Such expenses shall be paid by the Corporation in
advance of the final disposition of such action if the indemnified person
undertakes to repay such amounts if it is determined that he or she is not
entitled to indemnification.
 
    The Registrant has also entered into indemnification agreements with its 
officers and directors. The indemnification agreements require the Registrant 
to indemnify such persons in proceedings if such person acted in good faith 
and in a manner he or she reasonably believed to be in or not opposed to the 
best interests of the Registrant, provided no indemnification shall be made 
if the indemnitee is adjudged liable to the Company if applicable law 
prohibits such indemnification unless the court determines that 
indemnification may nevertheless be made by the Company. With respect to any 
crimimal proceeding other than one brought by or in the right of the 
Registrant, the indemnitee also must have no reasonable cause to believe his 
or her conduct was unlawful in order to gain indemnity.
 
    Reference is also made to Section (c) of the Underwriting Agreement entered
into by the Registrant in connection with its initial public offering of its
Common Stock indemnifying officers and directors of the Registrant against
certain liabilities. In addition, the Registrant has obtained directors and
officers' liability insurance covering, subject to certain exceptions, actions
taken by the Registrant's directors and officers in their capacities as such.
 
ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED
 
    Not Applicable
 
ITEM 8.  EXHIBITS
 
<TABLE>
<CAPTION>
  EXHIBIT
   NUMBER                                                 DOCUMENT                                                PAGE
------------  ------------------------------------------------------------------------------------------------  ---------
<S>           <C>                                                                                               <C>
       4.1(1)  Amended and Restated 1991 Stock Plan and form of agreement thereunder.
       4.2(2)  Amended 1995 Employee Stock Purchase Plan and forms of agreements thereunder.
       4.3(3)  1995 Directors' Stock Option Plan and form of agreement thereunder.
       4.4(4)  Assumed TyLink Corporation 1994 Equity Incentive Plan.
       4.5     Sync Research, Inc. 1996 Non-Executive Stock Option Plan.
       5.1     Opinion of Venture Law Group, A Professional Corporation, as to Legality of Securities Being
                 Registered.
      23.1     Consent of Venture Law Group, a Professional Corporation (contained in Exhibit 5.1 hereto).
      23.2     Consent of Ernst & Young LLP, Independent Auditors.
      23.3     Consent of Price Waterhouse LLP, Independent Accountants.
      24.1     Power of Attorney.
</TABLE>
 
------------------------
 
(1)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 1996, as filed with the Commission on August
     12, 1996.

(2)  Incorporated by reference from Registrant's Quarterly Report on Form 
     10-Q for the quarter ended September 30, 1996, as filed with the 
     Commission on November 14, 1996.

(3)  Incorporated by reference from Registrant's Registration Statement on Form
     S-1 (Registration No. 33-96910), as amended, filed with the Commission on
     September 14, 1995.
 
(4)  Incorporated by reference from Registrant's Registration Statement on 
     Form S-8 (Registration Statement No. 333-12315), filed with the 
     Commission on September 19, 1996.
 
                                      II-2
<PAGE>
ITEM 9.  UNDERTAKINGS
 
    A. The undersigned Registrant hereby undertakes:
 
    (1) To file, during any period in which offers or sales are being made, a
       post-effective amendment to this Registration Statement to include any
       material information with respect to the plan of distribution not
       previously disclosed in the Registration Statement or any material change
       to such information in the Registration Statement.
 
    (2) That, for the purpose of determining any liability under the Act, each
       such post-effective amendment shall be deemed to be a new registration
       statement relating to the securities offered therein, and the offering of
       such securities at that time shall be deemed to be the initial bona fide
       offering thereof.
 
    (3) To remove from registration by means of a post-effective amendment any
       of the securities being registered which remain unsold at the termination
       of the offering.
 
    B.  The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Act, each filing of the Registrant's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to Section 15(d) of the Exchange Act) that is incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
 
    C.  Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers and controlling persons of the Registrant
pursuant to the foregoing provisions, or otherwise, the Registrant has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.
 
                                      II-3
<PAGE>
                                   SIGNATURES
 
    Pursuant to the requirements of the Securities Act of 1933, the Registrant,
Sync Research, Inc., a corporation organized and existing under the laws of the
State of Delaware, certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Irvine, State of California, on May 30, 1997.
 
                                SYNC RESEARCH, INC.
 
                                By:            /s/ RONALD J. SCIOSCIA
                                     -----------------------------------------
                                                 Ronald J. Scioscia
                                           VICE PRESIDENT OF FINANCE AND
                                     ADMINISTRATION AND CHIEF FINANCIAL OFFICER
 
                                      II-4

<PAGE>
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
  EXHIBIT
   NUMBER
------------
 
<S>           <C>
       4.1(1) Amended and Restated 1991 Stock Plan and form of agreement thereunder.
 
       4.2(2) Amended 1995 Employee Stock Purchase Plan and forms of agreements thereunder.
 
       4.3(3) 1995 Directors' Stock Option Plan and form of agreement thereunder.
 
       4.4(4) Assumed TyLink Corporation 1994 Equity Incentive Plan.
 
       4.5    Sync Research, Inc. 1996 Non-Executive Stock Option Plan.
 
       5.1    Opinion of Venture Law Group, A Professional Corporation, as to legality of securities being registered.
 
      23.1    Consent of Venture Law Group, A Professional Corporation (included in Exhibit 5.1).
 
      23.2    Consent of Ernst & Young LLP, Independent Auditors.
 
      23.3    Consent of Price Waterhouse LLP, Independent Accountants.

      24.1    Powers of Attorney.
</TABLE>
 
------------------------

(1)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 1996, as filed with the Commission on August
     12, 1996.

(2)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended September 30, 1996, as filed with the Commission on 
     November 14, 1996.

(3)  Incorporated by reference from Registrant's Registration Statement on Form
     S-1, as amended (Registration No. 33-96910), filed with the Commission on
     September 14, 1995.

(4)  Incorporated by reference from Registrant's Registration Statement on 
     Form S-8 (Registration Statement No. 333-12315), filed with the Commission
     on September 19, 1996.
[{"type": "S-8", "sequence": "1", "description": "S-8", "secsgml_size_bytes": 17350}]
{"company-data": {"conformed-name": "SYNC RESEARCH INC", "cik": "0001000695", "assigned-sic": "3577", "irs-number": "330676350", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-28045", "film-number": "97616442"}, "business-address": {"street1": "7 STUDEBAKER", "city": "IRVINE", "state": "CA", "zip": "92718", "phone": "7145882070"}, "mail-address": {"street1": "7 STUDEBAKER", "city": "IRVINE", "state": "CA", "zip": "92718"}}
AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 30, 1997,
                             REGISTRATION NO.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                         ------------------------------
 
                                    FORM S-8
 
                             REGISTRATION STATEMENT
 
                                     UNDER
 
                           THE SECURITIES ACT OF 1933
                                ----------------
 
                              SYNC RESEARCH, INC.
             (Exact name of Registrant as specified in its charter)
DELAWARE                          3661                  33-0676350
 (State of other jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
incorporation or organization)                                      Number)
40 PARKER
                                IRVINE, CA 92618
                                 (714) 588-2070
         (Address, including zip code, and telephone number, including
            area code, of Registrant's principal executive offices)
 
            SYNC RESEARCH, INC. 1996 NON-EXECUTIVE STOCK OPTION PLAN
                            (Full title of the plan)
 
                         ------------------------------
 
                                ROGER A. DORF
                            CHIEF EXECUTIVE OFFICER
                              SYNC RESEARCH, INC.
                                   40 PARKER
                                IRVINE, CA 92618
                                 (714) 588-2070
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
 
                         ------------------------------
 
                                   COPIES TO:
                                MARK A. MEDEARIS
                               VENTURE LAW GROUP
                              2800 SAND HILL ROAD
                          MENLO PARK, CALIFORNIA 94025
                                 (415) 854-4488
 
                         ------------------------------
CALCULATION OF REGISTRATION FEE
PROPOSED MAXIMUM   PROPOSED MAXIMUM
                  TITLE OF SECURITIES                     AMOUNT TO BE    OFFERING PRICE       AGGREGATE          AMOUNT OF
                    TO BE REGISTERED                       REGISTERED        PER SHARE       OFFERING PRICE    REGISTRATION FEE
SYNC RESEARCH INC. 1996 NON-EXECUTIVE STOCK OPTION PLAN
  Common Stock, $0.001 par value........................   756,155(1)        $3.8832          $2,936,301.10         $889.79(2) 

  Common Stock, $0.001 par value........................    70,417           $4.0313          $  283,872.05         $ 86.02(3) 
                                                           -------                            -------------         -------    
                                                           826,572(1)                         $3,220,173.15         $975.81(2)
(1) This total represents a 826,572 share increase in the shares reserved for 
    issuance under the 1996 Non-Executive Stock Option Plan (the "Plan"), 
    which increase was approved by the Registrant's Board of Directors at 
    meetings and by actions taken by unanimous written consent of the board 
    of directors on September 27, 1996, November 26, 1996, January 8, 1997, 
    January 14, 1997, January 29, 1997 and March 7, 1997. Of the 826,572 shares
    being registered hereunder, 756,155 shares are subject to outstanding 
    options and 70,417 are available for issuance.  An additional 350,500 
    shares were registered for issuance under the Plan pursuant to a previous 
    registration statement on Form S-8 filed by the Registrant, (registration 
    number 333-12315) with the Commission on September 19, 1996.

(2) Computed in accordance with Rule 457(h) under the Securities Act of 1933
    solely for the purpose of calculating the registration fee. Computation
    based on the weighted average per share exercise price (rounded to nearest
    cent) of outstanding options under the referenced plan, the shares issuable
    under which are registered hereby.

(3) Estimated in accordance with Rule 457(h) and 457(c) under the Securities 
    Act of 1933 solely for the purpose of calculating the registration fee. 
    The computation with respect to unissued options is based on the 
    average of the high and low sale prices of the Common Stock as reported on 
    The Nasdaq National Market on May 22, 1997.
PART II
 
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

        The contents of the Registrant's previous Registration Statement on 
    Form S-8 (No. 333-12315) pertaining to the Sync Research, Inc. 1996 
    Non-Executive Stock Option Plan are hereby incorporated by reference 
    herein.

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE
 
    The following documents and information heretofore filed with the Securities
and Exchange Commission are hereby incorporated by reference:
 
    ITEM 3 (A)

        The Registrant's Annual Report on Form 10-K for the year ended 
    December 31, 1996, filed on March 31, 1997, pursuant to Section 13 of the 
    Securities Exchange Act of 1934, as amended (the "Exchange Act"), which 
    contains audited financial statements for the Registrant's latest fiscal 
    year for which such statements have been filed.
 
    ITEM 3 (B)
 
        The Registrant's Quarterly Report on Form 10-Q for the quarter ended 
    March 31, 1997, filed on May 12, 1997 pursuant to Section 13 of the 
    Exchange Act.
 
    ITEM 3 (C)
 
        Items 1 and 2 of the Registrant's Registration Statement on Form 8-A
    filed on October 10, 1995, and Items 1 and 2 of the Registrant's
    Registration Statement on Form 8-A, filed on November 4, 1995, each pursuant
    to Section 12 of the Exchange Act.
 
    All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered have been
sold or which deregisters all securities then remaining unsold, shall be deemed
to be incorporated by reference in this Registration Statement and to be part
hereof from the date of filing of such documents.
 
ITEM 4.  DESCRIPTION OF SECURITIES
 
    Not Applicable.
 
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL
 
    Not Applicable.
 
ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Section 145 of the Delaware General Corporation Law authorizes a court to
award, or a corporation's Board of Directors to grant indemnity to directors and
officers in terms sufficiently broad to permit such indemnification under
certain circumstances for liabilities (including reimbursement for expenses
incurred) arising under the Securities Act of 1933, as amended (the "Act").
 
    Article X of the Registrant's Amended and Restated Certificate of
Incorporation, filed November 17, 1995, provides for indemnification of its
directors, officers and employees to the maximum extent permitted by the
Delaware General Corporation Law.
 
                                      II-1
Article VI of the Registrant's Bylaws provides that the Registrant shall
indemnify its directors and officers to the fullest extent permitted by Delaware
law against expenses, judgments and other amounts actually and reasonably
incurred in connection with a proceeding arising from the person's status as an
agent of the Corporation. Such expenses shall be paid by the Corporation in
advance of the final disposition of such action if the indemnified person
undertakes to repay such amounts if it is determined that he or she is not
entitled to indemnification.
 
    The Registrant has also entered into indemnification agreements with its 
officers and directors. The indemnification agreements require the Registrant 
to indemnify such persons in proceedings if such person acted in good faith 
and in a manner he or she reasonably believed to be in or not opposed to the 
best interests of the Registrant, provided no indemnification shall be made 
if the indemnitee is adjudged liable to the Company if applicable law 
prohibits such indemnification unless the court determines that 
indemnification may nevertheless be made by the Company. With respect to any 
crimimal proceeding other than one brought by or in the right of the 
Registrant, the indemnitee also must have no reasonable cause to believe his 
or her conduct was unlawful in order to gain indemnity.
 
    Reference is also made to Section (c) of the Underwriting Agreement entered
into by the Registrant in connection with its initial public offering of its
Common Stock indemnifying officers and directors of the Registrant against
certain liabilities. In addition, the Registrant has obtained directors and
officers' liability insurance covering, subject to certain exceptions, actions
taken by the Registrant's directors and officers in their capacities as such.
 
ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED
 
    Not Applicable
 
ITEM 8.  EXHIBITS
EXHIBIT
   NUMBER                                                 DOCUMENT                                                PAGE
------------  ------------------------------------------------------------------------------------------------  ---------
4.1(1)  Amended and Restated 1991 Stock Plan and form of agreement thereunder.
       4.2(2)  Amended 1995 Employee Stock Purchase Plan and forms of agreements thereunder.
       4.3(3)  1995 Directors' Stock Option Plan and form of agreement thereunder.
       4.4(4)  Assumed TyLink Corporation 1994 Equity Incentive Plan.
       4.5     Sync Research, Inc. 1996 Non-Executive Stock Option Plan.
       5.1     Opinion of Venture Law Group, A Professional Corporation, as to Legality of Securities Being
                 Registered.
      23.1     Consent of Venture Law Group, a Professional Corporation (contained in Exhibit 5.1 hereto).
      23.2     Consent of Ernst & Young LLP, Independent Auditors.
      23.3     Consent of Price Waterhouse LLP, Independent Accountants.
      24.1     Power of Attorney.
------------------------
 
(1)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 1996, as filed with the Commission on August
     12, 1996.

(2)  Incorporated by reference from Registrant's Quarterly Report on Form 
     10-Q for the quarter ended September 30, 1996, as filed with the 
     Commission on November 14, 1996.

(3)  Incorporated by reference from Registrant's Registration Statement on Form
     S-1 (Registration No. 33-96910), as amended, filed with the Commission on
     September 14, 1995.
 
(4)  Incorporated by reference from Registrant's Registration Statement on 
     Form S-8 (Registration Statement No. 333-12315), filed with the 
     Commission on September 19, 1996.
 
                                      II-2
ITEM 9.  UNDERTAKINGS
 
    A. The undersigned Registrant hereby undertakes:
 
    (1) To file, during any period in which offers or sales are being made, a
       post-effective amendment to this Registration Statement to include any
       material information with respect to the plan of distribution not
       previously disclosed in the Registration Statement or any material change
       to such information in the Registration Statement.
 
    (2) That, for the purpose of determining any liability under the Act, each
       such post-effective amendment shall be deemed to be a new registration
       statement relating to the securities offered therein, and the offering of
       such securities at that time shall be deemed to be the initial bona fide
       offering thereof.
 
    (3) To remove from registration by means of a post-effective amendment any
       of the securities being registered which remain unsold at the termination
       of the offering.
 
    B.  The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Act, each filing of the Registrant's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to Section 15(d) of the Exchange Act) that is incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
 
    C.  Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers and controlling persons of the Registrant
pursuant to the foregoing provisions, or otherwise, the Registrant has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.
 
                                      II-3
SIGNATURES
 
    Pursuant to the requirements of the Securities Act of 1933, the Registrant,
Sync Research, Inc., a corporation organized and existing under the laws of the
State of Delaware, certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Irvine, State of California, on May 30, 1997.
 
                                SYNC RESEARCH, INC.
 
                                By:            /s/ RONALD J. SCIOSCIA
                                     -----------------------------------------
                                                 Ronald J. Scioscia
                                           VICE PRESIDENT OF FINANCE AND
                                     ADMINISTRATION AND CHIEF FINANCIAL OFFICER
 
                                      II-4
INDEX TO EXHIBITS
EXHIBIT
   NUMBER
------------
4.1(1) Amended and Restated 1991 Stock Plan and form of agreement thereunder.
 
       4.2(2) Amended 1995 Employee Stock Purchase Plan and forms of agreements thereunder.
 
       4.3(3) 1995 Directors' Stock Option Plan and form of agreement thereunder.
 
       4.4(4) Assumed TyLink Corporation 1994 Equity Incentive Plan.
 
       4.5    Sync Research, Inc. 1996 Non-Executive Stock Option Plan.
 
       5.1    Opinion of Venture Law Group, A Professional Corporation, as to legality of securities being registered.
 
      23.1    Consent of Venture Law Group, A Professional Corporation (included in Exhibit 5.1).
 
      23.2    Consent of Ernst & Young LLP, Independent Auditors.
 
      23.3    Consent of Price Waterhouse LLP, Independent Accountants.

      24.1    Powers of Attorney.
------------------------

(1)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 1996, as filed with the Commission on August
     12, 1996.

(2)  Incorporated by reference from Registrant's Quarterly Report on Form 10-Q
     for the quarter ended September 30, 1996, as filed with the Commission on 
     November 14, 1996.

(3)  Incorporated by reference from Registrant's Registration Statement on Form
     S-1, as amended (Registration No. 33-96910), filed with the Commission on
     September 14, 1995.

(4)  Incorporated by reference from Registrant's Registration Statement on 
     Form S-8 (Registration Statement No. 333-12315), filed with the Commission
     on September 19, 1996.