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                                                                 Exhibit 10.4

                                SYNC RESEARCH, INC.
               AMENDED AND RESTATED 1995 DIRECTORS' STOCK OPTION PLAN
                              (AMENDED JUNE 12, 1998)

 1.  ADOPTION AND PURPOSE.

     The Board of Directors of Sync Research, Inc. (the "Company") hereby adopts
the Sync Research, Inc. Amended and Restated 1995 Directors' Stock Option Plan
(the "Plan"). The purposes of the Plan are to compensate non-employee members of
the Board, to provide a means for such members to increase their holdings of
Company stock, and to attract and retain the best available personnel for
service as members of the Board. 

 2.  DEFINITIONS.

     The following definitions shall apply to this Plan: 

     (a)  "ANNUAL GRANT DATE" shall mean, for each calendar year, beginning in
1996, the date of each Annual Meeting of the Company's shareholders. 

     (b)  "BOARD" shall mean the Board of Directors of the Company. 

     (c)  "CODE" shall mean the Internal Revenue Code of 1986, as amended. 

     (d)  "COMPANY" shall have the meaning set forth in Section 1. 

     (e)  "EFFECTIVE DATE" shall mean the later of the date the Board approves
this Plan or the effective date of the Registration Statement on Form S-1 for
the initial public offering of the Company's Common Stock. 

     (f)  "ELIGIBLE DIRECTOR" shall mean any person who is a member of the Board
and who is not a full or part-time employee of the Company or of any subsidiary
or affiliate of the Company. The receipt of a director's fee from the Company
shall not be sufficient in and of itself to cause a person to be an employee of
the Company. 

     (g)  "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended. 

     (h)  "GRANT DATE" shall mean the Initial Grant Date or the Annual Grant
Date, as appropriate. 

     (i)  "INITIAL GRANT DATE" shall mean the later of the date on which an
Eligible Director is first elected to the Board or the Effective Date. 

     (j)  "OPTION" shall mean an option to purchase Shares granted under this
Plan. All Options shall be "nonstatutory options" (i.e., options that are not
intended to qualify as incentive stock options under Section 422 of the Code). 


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     (k)  "OPTION AGREEMENT" shall mean the written agreement described in
Section 6. 

     (l)  "PLAN" shall have the meaning set forth in Section 1. 

     (m)  "SHARES" shall mean shares of Common Stock of the Company.

 3.  ADMINISTRATION.

     (a)  GENERAL. This Plan shall be administered by the Board in accordance
with the express provisions of this Plan. 

     (b)  POWERS OF BOARD. Subject to the limitations set forth in this Plan,
the Board shall have full and complete authority to adopt such rules and
regulations and to make all such other determinations not inconsistent with the
Plan as may be necessary for the administration of the Plan. 

 4.  SHARES SUBJECT TO PLAN.

     (a)  AGGREGATE NUMBER. Subject to adjustment in accordance with Section
6(g), an aggregate of 200,000 Shares is reserved for issuance under this Plan.
Shares sold under this Plan may be unissued Shares or reacquired Shares. If any
Options shall for any reason terminate or expire without having been exercised
in full, Shares not purchased thereunder shall be available again for grant
under this Plan. 

     (b)  RIGHTS AS SHAREHOLDER. An Eligible Director shall have no rights as 
a shareholder with respect to Shares acquired by exercise of an Option until 
the issuance (as evidenced by an appropriate entry on the books of the 
Company or a duly authorized transfer agent) of a stock certificate 
evidencing the Shares. Subject to Section 6(g), no adjustment shall be made 
for dividends or other events for which the record date is prior to the date 
the certificate is issued.

 5.  NONDISCRETIONARY GRANTS.

     All grants of Options hereunder shall be automatic and non-discretionary
and shall be made strictly in accordance with the following provisions: 

     (a)  INITIAL GRANT.  Each person who becomes an Eligible Director on or
after the Effective Date shall automatically receive on the Initial Grant Date
for such Eligible Director an Option to purchase 40,000 Shares.

     (b)  REGULAR ANNUAL GRANTS. On each Annual Grant Date, each Eligible
Director who has been such for at least six (6) months and remains such as of
such date shall receive the grant of an Option to purchase 10,000 Shares. 


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     (c)  ADJUSTMENT. The number of Shares for which options are granted in
accordance with this Section 5 and the number of Shares subject to any Option
shall be subject to adjustment in accordance with Section 6(g). 

     (d)  NO DISCRETION; EXCESS SHARES. No person shall have any discretion to
select which Eligible Directors shall be granted Options or to determine the
number of Shares to be subject to such Options. In the event that a grant would
cause the number of Shares subject to outstanding Options plus the number of
Shares previously purchased upon exercise of Options to exceed the number set
forth in Section 4(a), then each Option so granted shall be for that number of
Shares determined by dividing the remaining Shares available for grant by the
number of Eligible Directors receiving Options at such time. 

     (e)  Notwithstanding the foregoing, each Eligible Director who received an
Option on an Initial Grant Date on or after January 30, 1998 and prior to June
12, 1998 in the amount of 20,000 shares, shall be automatically granted, on the
date of the Company's first Annual Meeting of Stockholders after January 30,
1998 at which the amendments to this Plan are approved by the Company's
stockholders, an Option in the amount of 20,000 shares at the applicable
exercise price on the grant date pursuant to Section 6(c); PROVIDED that such
Eligible Director remains a member of the Company's Board of Directors
immediately following such meeting.

 6.  TERMS OF OPTION AGREEMENTS.

     Upon the grant of each Option, the Company and the Eligible Director shall
enter into an Option Agreement which shall specify the Grant Date and the
exercise price, and shall include or incorporate by reference the substance of
all of the following provisions and such other provisions consistent with this
Plan as the Board may determine: 

     (a)  TERM. The term of the Option shall expire 10 years from its Grant
Date, subject to earlier termination in accordance with Sections 6(f) or 6(h). 

     (b)  OPTION EXERCISE. Each Option held by an Eligible Director that is
received on either an Initial Grant Date or an Annual Grant Date shall initially
be non-exercisable but shall become exercisable as to 1/4 of the Shares subject
to such Option on the date which is one year after such Initial Grant Date or
Annual Grant Date, as the case may be, and at the rate of 1/48th of the Shares
subject to such Option for each month thereafter, provided, in each case, that
the holder thereof remains an Eligible Director as of such date.  The
exercisability of an Option shall also be subject to the effectiveness of any
registration statement or qualification required by applicable law with respect
to the issuance of the Shares reserved under the Plan. 

     (c)  PURCHASE PRICE. The purchase price of the Shares subject to each
Option shall be their fair market value determined based on the closing sales
price for Shares or the closing bid if no sales were reported, as quoted on the
Nasdaq National Market, on the Grant Date of such Option, or on the last
preceding business day if such Grant Date is not a business day. 


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     (d)  PAYMENT OF PURCHASE PRICE. The purchase price of Shares acquired
pursuant to an option shall be paid in full at the time the Option is exercised
in cash, by check or by delivery of Shares having a fair market value on the
date of exercise (determined in the same manner as the purchase price is
determined) equal to the aggregate purchase price (and, if such Shares were
acquired from the Company, shall have been held for at least six months) or by
some combination of the foregoing. 

     (e)  TRANSFERABILITY. No Option shall be transferable otherwise than by
will or the laws of descent and distribution or pursuant to a qualified domestic
relations order (as defined by the Code or the rules thereunder). 

     (f)  TERMINATION OF MEMBERSHIP ON THE BOARD. If an Eligible Director's
membership on the Board terminates for any reason, an Option held at the date of
termination which is then exercisable under the terms of Section 6(b) may be
exercised in whole or in part at any time within thirty (30) days after the date
of such termination (but in no event after the term of the Option expires). Any
Option not so exercised shall thereafter terminate. 

     (g)  CAPITALIZATION CHANGES. If any change is made in the Shares subject to
the Plan or subject to any Option granted under the Plan, through merger,
consolidation, reorganization, recapitalization, stock dividend, dividend in
property other than cash, stock split, liquidating dividend, combination of
shares, exchange of shares, change in corporate structure or otherwise, the
Board shall make appropriate adjustments as to the maximum number of Shares
subject to the Plan, the number of Shares covered by any Option grant, the
maximum number of Shares for which Options may be granted to any Eligible
Director, and the number of Shares and price per Share covered by outstanding
Options. 

     (h)  CHANGE OF OWNERSHIP. In the event of (i) a dissolution or liquidation
of the Company, (ii) a sale of all or substantially all of the Company's assets,
(iii) a merger or consolidation in which the Company is not the surviving
corporation, or (iv) any other capital reorganization in which more than fifty
percent (50%) of the shares of the Company entitled to vote are exchanged, the
Eligible Director shall have a reasonable time following the adoption of the
plan for liquidation, dissolution, sale, merger, consolidation or reorganization
to exercise the Option, including any part of the Option that would not
otherwise be exercisable under Section 6(b), prior to the effectiveness of such
liquidation, dissolution, sale, merger, consolidation or reorganization, at the
end of which time the Option shall terminate, unless the Eligible Director has
the right to exercise the Option, including any part of the Option that would
not otherwise be exercisable under Section 6(b), or to receive a substitute
option with comparable terms, as to an equivalent number of shares of stock of
the corporation succeeding the Company or acquiring its business by reason of
such liquidation, dissolution, sale, merger, consolidation or reorganization. 

 7.  USE OF PROCEEDS.

     Proceeds from the sale of Shares pursuant to this Plan shall be used by the
Company for general corporate purposes. 


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 8.  AMENDMENT OF PLAN.

     The Board may amend the Plan at any time, provided that any amendment which
increases the number of shares as to which Options may be granted, modifies the
requirements as to eligibility for participation, materially increases the
benefits accruing under the Plan or otherwise must be approved by shareholders
to comply with Rule 16b-3 of the Exchange Act, shall be subject to obtaining new
shareholder approval as provided in Section 11. No amendment shall affect the
rights of the holder of any Option, except with that holder's consent.
Notwithstanding anything to the contrary in this Plan, the provisions set forth
in Section 5 (and any other Sections of the Plan that affect the formula award
terms required to be specified by Rule 16b-3) shall not be amended more than
once every six (6) months, other than to comply with changes in the Code, the
Employee Retirement Income Security Act of 1974, or the rules thereunder. 

 9.  TERMINATION OR SUSPENSION OF PLAN.

     The Board at any time may suspend or terminate this Plan. This Plan, unless
sooner terminated, shall terminate on the tenth anniversary of its adoption by
the Board. No Option may be granted under this Plan while this Plan is suspended
or after it is terminated. Suspension or termination of this Plan shall not
affect the rights of the holder of any Option, except with that holder's
consent. 

 10.  CONDITIONS UPON ISSUANCE OF SHARES.  

     (a)  COMPLIANCE. Shares shall not be issued pursuant to the exercise of an
Option unless the exercise of such Option and the issuance and delivery of such
Shares pursuant thereto shall comply with all relevant provisions of law,
including, without limitation, the Securities Act of 1933, as amended, the
Exchange Act, the rules and regulations promulgated thereunder, state securities
laws, and the requirements of any stock exchange upon which the Shares may then
be listed, and shall be further subject to the approval of counsel for the
Company with respect to such compliance. 

     (b)  CONDITION TO EXERCISE. As a condition to the exercise of an Option,
the Company may require the person exercising such Option to represent and
warrant at the time of any such exercise that the Shares are being purchased
only for investment and without any present intention to sell or distribute such
Shares, if, in the opinion of counsel for the Company, such a representation is
required by any of the aforementioned relevant provisions of law. 

     (c)  NO LIABILITY. Inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company's
counsel to be necessary to the lawful issuance and sale of any Shares hereunder,
shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained. 

 11.  SHAREHOLDER APPROVAL.


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     This Plan is subject to approval by the shareholders of the Company within
12 months after the date the Board approves this Plan either by the written
consent of the holders of a majority of the outstanding shares of capital stock
or by the affirmative vote of a majority of the votes cast at a duly held
shareholders' meeting at which a quorum of the voting power of the Company is
represented in person or by proxy. Options may be granted, but not exercised,
before such shareholder approval. If the shareholders fail to approve this Plan
within the required time period, any Options granted under this Plan shall be
void, and no additional Options shall be granted. 

 12.  ADDITIONAL RESTRICTIONS OF RULE 16b-3.

     The terms and conditions of Options granted hereunder shall comply with the
applicable provisions of Rule 16b-3. This Plan and the Options granted hereunder
shall be deemed to contain such additional conditions and restrictions as may be
required for this Plan to qualify as a "formula plan" under Rule 16b-3, as then
applicable to the Company, and to qualify for the maximum exemptions from
Section 16 of the Exchange Act with respect to Plan transactions.


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                                SYNC RESEARCH, INC.
                                          
                         1995 DIRECTORS' STOCK OPTION PLAN
                                          
                            NOTICE OF STOCK OPTION GRANT




Optionee
Address


     You have been granted an option to purchase Common Stock of Sync Research,
Inc. (the "Company") as follows:

     Date of Grant                      Date of Grant

     Vesting Commencement Date          Vest Commencement Date

     Exercise Price per Share           $ Exercise Price Per Shar

     Total Number of Shares Granted     Total Number Shares Gra

     Total Exercise Price               $ TotalExercisePrice

     Expiration Date                    ExpirationDate

     Vesting Schedule                   This Option may be exercised, in whole
                                        or in part, in accordance with the
                                        following schedule:  1/4th of the shares
                                        subject to this option vest one year
                                        after the Date of Grant and 1/48th of
                                        such shares vest on the monthly
                                        anniversary thereafter.
     
                                        Termination Period  This Option may be
                                        exercised for 30 days after termination
                                        of Optionee's status as an Eligible
                                        Director, but in no event later than the
                                        Term/Expiration Date as provided above.


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     By your signature and the signature of the Company's representative below,
you and the Company agree that this option is granted under and governed by the
terms and conditions of the 1995 Directors' Stock Option Plan and the
Nonstatutory Stock Option Agreement, all of which are attached and made a part
of this document.


OPTIONEE:                               SYNC RESEARCH, INC.


                                        By:
-----------------------------------        -----------------------------------
Signature


                                        Title:
-----------------------------------           --------------------------------
Print Name




                                       2

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                                 SYNC RESEARCH, INC.
                                          
                        NONSTATUTORY STOCK OPTION AGREEMENT
                                          
                                          

     1.   GRANT OF OPTION.  The Board of Directors of the Company hereby grants
to the Optionee named in the Notice of Stock Option Grant attached as Part I of
this Agreement (the "Optionee"), an option (the "Option") to purchase a number
of Shares, as set forth in the Notice of Stock Option Grant, at the exercise
price per share set forth in the Notice of Stock Option Grant (the "Exercise
Price"'), subject to the terms and conditions of the 1995 Directors' Stock
Option Plan (the "Plan"), which is incorporated herein by reference.
(Capitalized terms not defined herein shall have the meanings ascribed to such
terms in the Plan.) In the event of a conflict between the terms and conditions
of the Plan and the terms and conditions of this Nonstatutory Stock Option
Agreement, the terms and conditions of the Plan shall prevail.

     2.   EXERCISE OF OPTION.

          (a)  RIGHT TO EXERCISE.  This Option is exercisable during its term in
accordance with the Vesting Schedule set out in the Notice of Stock Option Grant
and the applicable provisions of the Plan and this Nonstatutory Stock Option
Agreement.  In the event of Optionee's death, disability or other termination of
Optionee's employment or consulting relationship, the exercisability of the
Option is governed by the applicable provisions of the Plan and this
Nonstatutory Stock Option Agreement.

          (b)  METHOD OF EXERCISE.  This Option is exercisable by delivery of an
exercise notice, in the form attached as Exhibit A (the "Exercise Notice"),
which shall state the election to exercise the Option, the number of Shares in
respect of which the Option is being exercised (the "Exercised Shares"), and
such other representations and agreements as may be required by the Company
pursuant to the provisions of the Plan.  The Exercise Notice shall be signed by
the Optionee and shall be delivered in person or by certified mail to the
Secretary of the Company.  The Exercise Notice shall be accompanied by payment
of the aggregate Exercise Price as to all Exercised Shares.  This Option shall
be deemed to be exercised upon receipt by the Company of such fully executed
Exercise Notice accompanied by such aggregate Exercise Price.

          No Shares shall be issued pursuant to the exercise of this Option
unless such issuance and exercise complies with all relevant provisions of law
and the requirements of any stock exchange or quotation service upon which the
Shares are then listed.  Assuming such compliance, for income tax purposes the
Exercised Shares shall be considered transferred to the Optionee on the date the
Option is exercised with respect to such Exercised Shares.

     3.   METHOD OF PAYMENT.  Payment of the aggregate Exercise Price shall be
by any of the following, or a combination thereof, at the election of the
Optionee:

          (a)  cash; 


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          (b)  check;

          (c)  delivery of a properly executed exercise notice together with
such other documentation as the Administrator and the broker, if applicable,
shall require to effect an exercise of the Option and delivery to the Company of
the sale or loan proceeds required to pay the exercise price; or

          (d)  surrender of other Shares which (i) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares.

     4.   NON-TRANSFERABILITY OF OPTION.  This Option may not be transferred in
any manner otherwise than by will or by the laws of descent or distribution or
pursuant to a domestic relations order (as defined by the Code or the rules
thereunder) and may be exercised during the lifetime of Optionee only by the
Optionee or a transferee permitted by Section 6 of the Plan.  The terms of the
Plan and this Nonstatutory Stock Option Agreement shall be binding upon the
executors, administrators, heirs, successors and assigns of the Optionee.

     5.   TERM OF OPTION.  This Option may be exercised only within the term set
out in the Notice of Stock Option Grant, and may be exercised during such term
only in accordance with the Plan and the terms of this Nonstatutory Stock Option
Agreement.

     6.   TAX CONSEQUENCES.  Set forth below is a brief summary of certain
federal and California tax consequences relating to this Option under the law in
effect as of the date of grant.  THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE
TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE.  OPTIONEE SHOULD CONSULT HIS OR
HER OWN TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE SHARES.

          (a)  EXERCISING THE OPTION.  Since this Option does not qualify as an
incentive stock option under Section 422 of the Code, the Optionee may incur
regular federal and California income tax liability upon exercise.  The Optionee
will be treated as having received compensation income (taxable at ordinary
income tax rates) equal to the excess, if any, of the fair market value of the
Exercised Shares on the date of exercise over their aggregate Exercise Price.  

          (b)  DISPOSITION OF SHARES.  If the Optionee holds the Option Shares
for more than one year, gain realized on disposition of the Shares will be
treated as long-term capital gain for federal and California income tax
purposes. 

                                       2


<PAGE>

     By your signature and the signature of the Company's representative below,
you and the Company agree that this Option is granted under and governed by the
terms and conditions of the Plan and this Nonstatutory Stock Option Agreement. 
Optionee has reviewed the Plan and this Nonstatutory Stock Option Agreement in
their entirety, has had an opportunity to obtain the advice of counsel prior to
executing this Nonstatutory Stock Option Agreement and fully understands all
provisions of the Plan and Nonstatutory Stock Option Agreement.  Optionee hereby
agrees to accept as binding, conclusive and final all decisions or
interpretations of the Administrator upon any questions relating to the Plan and
Nonstatutory Stock Option Agreement.
     

SYNC RESEARCH, INC.


By:                                       
  ---------------------------------       -----------------------------------
                                          Optionee

Title:
      ----------------------------

                                       3


<PAGE>

                                  CONSENT OF SPOUSE

     The undersigned spouse of Optionee has read and hereby approves the 
terms and conditions of the Plan and this Nonstatutory Stock Option 
Agreement.  In consideration of the Company's granting his or her spouse the 
right to purchase Shares as set forth in the Plan and this Nonstatutory Stock 
 Option Agreement, the undersigned hereby agrees to be irrevocably bound by 
the terms and conditions of the Plan and this Nonstatutory Stock Option 
Agreement and further agrees that any community property interest shall be 
similarly bound.  The undersigned hereby appoints the undersigned's spouse as 
attorney-in-fact for the undersigned with respect to any amendment or 
exercise of rights under the Plan or this Nonstatutory Stock Option Agreement.



                                        ------------------------------------
                                        Spouse of Optionee