EXHIBIT 5.1
 
                                      May 30, 1997
 
Sync Research, Inc.
40 Parker
Irvine, CA 92618

    REGISTRATION STATEMENT ON FORM S-8
 
Ladies and Gentlemen:
 
    We have examined the Registration Statement on Form S-8 to be filed by 
you with the Securities and Exchange Commission on or about May 30, 1997 
(the "Registration Statement") in connection with the registration under the 
Securities Act of 1933, as amended, of a total of 826,572 shares of your 
Common Stock (the "Shares") reserved for issuance under the Sync Research, 
Inc. 1996 Non-Executive Stock Option Plan (the "Plan"). As your legal 
counsel, we have examined the proceedings taken and are familiar with the 
proceedings proposed to be taken by you in connection with the sale and 
issuance of the Shares under the Plan.
 
    It is our opinion that, when issued and sold in the manner referred to in
the Plan and pursuant to the respective agreement which accompanies each grant
under the plan, the Shares will be legally and validly issued, fully paid and
nonassessable.
 
    We consent to the use of this opinion as an exhibit to the Registration
Statement and further consent to the use of our name wherever it appears in the
Registration Statement and any amendments to it.
 
                                        Sincerely,
 
                                        VENTURE LAW GROUP
                                        A Professional Corporation