<PAGE>

                                    [LETTER HEAD]

                                 AMENDED SCHEDULE TO

                             LOAN AND SECURITY AGREEMENT

BORROWER:      SYNC RESEARCH, INC.
ADDRESS:       40 PARKER
               IRVINE, CALIFORNIA  92718

DATED AS OF: DECEMBER 3, 1997



CREDIT LIMIT
(Section 1.1):           An amount not to exceed $5,000,000 at any one time
                         outstanding; PROVIDED, HOWEVER, that upon a Post-IPO
                         Default (as defined in Section 2.2 of the Loan
                         Agreement as set forth in the Amendment to Loan and
                         Security Agreement dated October 5, 1995 between
                         Silicon and Borrower), the Credit Limit shall be an
                         amount not to exceed the lesser of:  (i) $5,000,000 at
                         any one time outstanding; or (ii) 70% of the Net Amount
                         of Borrower's accounts, which Silicon in its discretion
                         deems eligible for borrowing.  "Net Amount" of an
                         account means the gross amount of the account, minus
                         all applicable sales, use, excise and other similar
                         taxes and minus all discounts, credits and allowances
                         of any nature granted or claimed.

                         Without limiting the fact that the determination of
                         which accounts are eligible for borrowing is a matter
                         of Silicon's discretion, the following will not be
                         deemed eligible for borrowing:  accounts outstanding
                         for more than 90 days from the invoice date, accounts
                         subject to any contingencies, accounts owing from any
                         government agency (unless Borrower completes such
                         assignment of claims documentation and other
                         documentation that Silicon determines is necessary or
                         desirable to perfect and protect the interest of
                         Silicon therein), accounts owing from an account debtor
                         outside the United States (unless pre-approved by
                         Silicon in its discretion, or backed by a letter of
                         credit satisfactory to Silicon, or FCIA insured
                         satisfactory to Silicon), accounts owing from one
                         account debtor to the extent they exceed 25% of the
                         total eligible accounts outstanding*, accounts owing
                         from an affiliate of Borrower**, and accounts owing
                         from an account debtor to whom Borrower is or may be
                         liable for goods purchased from such account debtor or
                         otherwise.  In addition, if more than 50% of the
                         accounts owing from an account debtor are outstanding
                         more than 90 days from the invoice date or are
                         otherwise not eligible accounts, then all accounts
                         owing from that account debtor will be deemed
                         ineligible for borrowing.

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     SILICON VALLEY BANK                  AMENDED SCHEDULE TO LOAN AGREEMENT
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                         *PROVIDED THAT ACCOUNTS OWING FROM AT&T, IBM, 3 COM,
                         AND RACAL-DATACOM SHALL BE DEEMED INELIGIBLE TO THE
                         EXTENT ANY SUCH ACCOUNTS EXCEED 40% OF THE TOTAL
                         ELIGIBLE ACCOUNTS OUTSTANDING

                         **(OTHER THAN 3 COM)

                         Silicon, in its reasonable discretion, will from time
                         to time during the term of this Agreement issue letters
                         of credit for the account of the Borrower ("Letters of
                         Credit"), in an aggregate amount at any one time
                         outstanding not to exceed $1,000,000, upon the request
                         of the Borrower, provided that, on the date the Letters
                         of Credit are to be issued, Borrower has available to
                         it Accounts Loans in an amount equal to or greater than
                         the face amount of the Letters of Credit to be issued.
                         Prior to the issuance of any Letters of Credit,
                         Borrower shall execute and deliver to Silicon
                         Applications for Letters of Credit and such other
                         documentation as Silicon shall specify (the "Letter of
                         Credit Documentation").  Fees for the Letters of Credit
                         shall be as provided in the Letter of Credit
                         Documentation.   Letters of Credit may have a maturity
                         date up to twelve months beyond the Maturity Date in
                         effect from time to time, provided that if on the
                         Maturity Date, or on any earlier effective date of
                         termination, there are any outstanding letters of
                         credit issued by Silicon or issued by another
                         institution based upon an application, guarantee,
                         indemnity or similar agreement on the part of Silicon,
                         then on such date Borrower shall provide to Silicon
                         cash collateral in an amount equal to the face amount
                         of all such letters of credit plus all interest, fees
                         and cost due or to become due in connection therewith,
                         to secure all of the Obligations relating to said
                         letters of credit, pursuant to Silicon's then standard
                         form cash pledge agreement.

                         The Credit Limit set forth above and the Loans
                         available under this Agreement at any time shall be
                         reduced by the face amount of Letters of Credit from
                         time to time outstanding.

FOREIGN EXCHANGE
 CONTRACT SUBLIMIT       Up to $1,000,000 of the Credit Limit (the "Contract
                         Limit") may be utilized for spot and future foreign
                         exchange contracts (the "Exchange Contracts").  The
                         Credit Limit shall be reduced by the following amounts
                         (the "Foreign Exchange Reserve") on each day (the
                         "Determination Date"):  (i) on all outstanding Exchange
                         Contracts on which delivery is to be effected or
                         settlement allowed more than two business days from the
                         Determination Date, 10% of the gross amount of the
                         Exchange Contracts; plus (ii) on all outstanding
                         Exchange Contracts on which delivery is to be effected
                         or settlement allowed within two business days after
                         the Determination Date, 100% of the gross amount of the
                         Exchange Contracts.  In lieu of the Foreign Exchange
                         Reserve for 100% of the gross amount of any Exchange
                         Contract, the Borrower may request that Silicon debit
                         the Borrower's bank account with Silicon for such
                         amount, provided Borrower has immediately available
                         funds in such amount in its bank account.

                         Silicon may, in its discretion, terminate the Exchange
                         Contracts at any time (a) that an Event of Default
                         occurs or (b) that there is not


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     SILICON VALLEY BANK                  AMENDED SCHEDULE TO LOAN AGREEMENT
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                         sufficient availability under the Credit Limit and
                         Borrower does not have available funds in its bank
                         account to satisfy the Foreign Exchange Reserve.  If
                         either Silicon or Borrower terminates the Exchange
                         Contracts, and without limitation of the FX Indemnity
                         Provisions (as referred to below), Borrower agrees to
                         reimburse Silicon for any and all fees, costs and
                         expenses relating thereto or arising in connection
                         therewith.

                         Borrower shall not permit the total gross amount of all
                         Exchange Contracts on which delivery is to be effected
                         and settlement allowed in any two business day period
                         to be more than $500,000 (the "Settlement Limit"), nor
                         shall Borrower permit the total gross amount of all
                         Exchange Contracts to which Borrower is a party,
                         outstanding at any one time, to exceed the Contract
                         Limit.

                         Notwithstanding the above, however, the amount which
                         may be settled in any two (2) business day period may,
                         in Silicon's sole discretion, be increased above the
                         Settlement Limit up to, but in no event to exceed, the
                         amount of the Contract Limit (the "Discretionary
                         Settlement Amount") under either of the following
                         circumstances (the "Discretionary Settlement
                         Circumstances"):

                           (i) if there is sufficient availability under the
                           Credit Limit in the amount of the Foreign Exchange
                           Reserve as of each Determination Date, and Silicon
                           in advance shall reserve the full amount of the
                           Foreign Exchange Reserve against the Credit Limit;
                           or

                           (ii) if there is insufficient availability under the
                           Credit Limit as to settlements within any two (2)
                           business day period, and if Silicon is able to: (A)
                           verify good funds overseas prior to crediting
                           Borrower's deposit account with Silicon (in the case
                           of Borrower's sale of foreign currency); or (B)
                           debit Borrower's deposit account with Silicon prior
                           to delivering foreign currency overseas (in the case
                           of Borrower's purchase of foreign currency);

                         PROVIDED that it is expressly understood that Silicon's
                         willingness to adopt the Discretionary Settlement
                         Amount is a matter of Silicon's sole discretion and the
                         existence of the Discretionary Settlement Circumstances
                         in no way means or implies that Silicon shall be
                         obligated to permit the Borrower to exceed the
                         Settlement Limit in any two business day period.

                         In the case of Borrower's purchase of foreign currency,
                         Borrower shall instruct Silicon in advance upon
                         settlement either to treat the settlement amount as an
                         advance under the Credit Limit, or to debit Borrower's
                         account for the amount settled.

                         The Borrower shall execute all standard form
                         applications and agreements of Silicon in connection
                         with the Exchange Contracts, and without limiting any
                         of the terms of such applications and agreements, the
                         Borrower will pay all standard fees and charges of
                         Silicon in connection with the Exchange Contracts.


                                         -3-
<PAGE>

     SILICON VALLEY BANK                  AMENDED SCHEDULE TO LOAN AGREEMENT
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                         Without limiting any of the other terms of this Loan
                         Agreement or any such standard form applications and
                         agreements of Silicon, Borrower agrees to indemnify
                         Silicon and hold it harmless, from and against any and
                         all claims, debts, liabilities, demands, obligations,
                         actions, costs and expenses (including, without
                         limitation, attorneys' fees of counsel of Silicon's
                         choice), of every nature and description, which it may
                         sustain or incur, based upon, arising out of, or in any
                         way relating to any of the Exchange Contracts or any
                         transactions relating thereto or contemplated thereby
                         (collectively referred to as the "FX Indemnity
                         Provisions").

                         The Exchange Contracts shall have maturity dates no
                         later than the Maturity Date.

INTEREST RATE
(Section 1.2):           A rate equal to the "Prime Rate" in effect from time to
                         time, per annum, calculated on the basis of a 360-day
                         year for the actual number of days elapsed.  "Prime
                         Rate" means the rate announced from time to time by
                         Silicon as its "prime rate;" it is a base rate upon
                         which other rates charged by Silicon are based, and it
                         is not necessarily the best rate available at Silicon.
                         The interest rate applicable to the Obligations shall
                         change on each date there is a change in the Prime
                         Rate.

FACILITY FEE
(Section 1.3):           As per the Amendment to Loan Agreement of even date.

MATURITY DATE
(Section 5.1):           OCTOBER 5, 1998

PRIOR NAMES OF BORROWER
(Section 3.2):           FALLON & ASSOCIATES, SPECTRUM COMMUNICATIONS, INC.,
                         TYLINK CORPORATION

TRADE NAMES OF BORROWER
(Section 3.2):           SYNCVIEW, INTERNETWORKING SNA


OTHER LOCATIONS AND
ADDRESSES (Section 3.3): 10C COMMERCE WAY, NARRON, MA  02766

MATERIAL ADVERSE
LITIGATION
(Section 3.10):          AS DISCLOSED IN THE BORROWER'S SEPTEMBER 30, 1997 10-Q
                         REPORT

NEGATIVE COVENANTS-
EXCEPTIONS(Section 4.6): Without Silicon's prior written consent, Borrower may
                         do the following, provided that, after giving effect
                         thereto, no Event of Default has occurred and no event
                         has occurred which, with notice or passage of time or
                         both, would constitute an Event of Default, and
                         provided that the following are done in compliance with
                         all applicable laws, rules and regulations:  (i)
                         repurchase shares of Borrower's stock pursuant to any
                         employee stock purchase or benefit plan, provided that
                         the total amount paid by Borrower for such stock does
                         not exceed $75,000 in any fiscal year.


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     SILICON VALLEY BANK                  AMENDED SCHEDULE TO LOAN AGREEMENT
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FINANCIAL COVENANTS
(Section 4.1):           Borrower shall comply with all of the following
                         covenants.  Compliance shall be determined as of the
                         end of each fiscal quarter, except as otherwise
                         specifically provided below:

     QUICK ASSET RATIO:  Borrower shall maintain a ratio of "Quick Assets" to
                         current liabilities of not less than 3.5 to 1.


     TANGIBLE NET WORTH: Borrower shall maintain a tangible net worth of not
                         less than $27,500,000, provided that tangible net worth
                         shall be computed excluding loans by the Borrower to
                         its officers.
     DEBT TO TANGIBLE
     NET WORTH RATIO:    Borrower shall maintain a ratio of total liabilities to
                         tangible net worth of not more than .40 to 1.

     PROFITABILITY:      Borrower shall not incur a loss (after taxes) for the
                         fiscal year ending December 31, 1998.

     DEFINITIONS:        "Current assets," and "current liabilities" shall have
                         the meanings ascribed to them in accordance with
                         generally accepted accounting principles.

                         "Tangible net worth" means the excess of total assets
                         over total liabilities, determined in accordance with
                         generally accepted accounting principles, excluding
                         however all assets which would be classified as
                         intangible assets under generally accepted accounting
                         principles, including without limitation goodwill,
                         licenses, patents, trademarks, trade names, copyrights,
                         and franchises.

                         "Quick Assets" means cash on hand or on deposit in
                         banks, readily marketable securities issued by the
                         United States, readily marketable commercial paper
                         rated "A-1" by Standard & Poor's Corporation (or a
                         similar rating by a similar rating organization),
                         certificates of deposit and banker's acceptances, and
                         accounts receivable (net of allowance for doubtful
                         accounts).

     SUBORDINATED DEBT:  "Liabilities" for purposes of the foregoing covenants
                         do not include indebtedness which is subordinated to
                         the indebtedness to Silicon under a subordination
                         agreement in form specified by Silicon or by language
                         in the instrument evidencing the indebtedness which is
                         acceptable to Silicon.

OTHER COVENANTS
     (Section 4.1):      Borrower shall at all times comply with all of the
                         following additional covenants:

                         1.   BANKING RELATIONSHIP.  Borrower shall at all times
                         maintain its primary banking relationship with Silicon.

                         2.   MONTHLY BORROWING BASE CERTIFICATE AND LISTING.
                         After the occurrence of a Post-IPO Default, within 20
                         days after the end of each month thereafter (including
                         any month in which the Post-IPO Default



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     SILICON VALLEY BANK                  AMENDED SCHEDULE TO LOAN AGREEMENT
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                         occurs), Borrower shall provide Silicon with a
                         Borrowing Base Certificate in such form as Silicon
                         shall specify, and an aged listing of Borrower's
                         accounts receivable and accounts payable.

                         3.   INDEBTEDNESS.  Without limiting any of the
                         foregoing terms or provisions of this Agreement,
                         Borrower shall not in the future incur indebtedness for
                         borrowed money, except for (i) indebtedness to Silicon,
                         and (ii) indebtedness incurred in the future for the
                         purchase price of or lease of equipment in an aggregate
                         amount not exceeding $250,000 at any time outstanding.

                         4.   [RESERVED.]

                         5.   NEGATIVE PLEDGE.  Borrower shall not grant a
                         security interest in any of its present or future
                         Collateral, other than for specific liens on capital
                         equipment relating to obligations incurred pursuant to
                         paragraph 3 above and a lien in favor of Silicon.

                         6.   AGREEMENT TO TERMINATE SECURITY INTEREST UPON IPO;
                         POST-IPO DEFAULT UCCS; ETC.  Due to the prior
                         completion of the IPO Consummation, Silicon has
                         terminated its security interest in the Collateral.
                         Notwithstanding the foregoing, upon the occurrence of a
                         Post-IPO Default, Borrower agrees that Borrower shall
                         be deemed to have granted to Silicon a security
                         interest in the Collateral as set forth in Section 2.2
                         hereof at such time, and that Borrower agrees to
                         execute and deliver to Silicon forthwith such UCC
                         financing statements, instruments and other
                         documentation as Silicon determines is necessary or
                         desirable in connection therewith in order to perfect
                         and otherwise protect its security interest in the
                         Collateral.


                         BORROWER:

                            SYNC RESEARCH, INC.

                            BY
                              ---------------------------------------
                               PRESIDENT OR VICE PRESIDENT

                            BY
                              ---------------------------------------
                               SECRETARY OR ASS'T SECRETARY

                         SILICON:

                            SILICON VALLEY BANK


                            BY
                              ---------------------------------------

                            TITLE
                                  -----------------------------------




                                         -6-

<PAGE>

                                    [LETTER HEAD]

                       AMENDMENT TO LOAN AND SECURITY AGREEMENT

BORROWER:      SYNC RESEARCH, INC.
ADDRESS:       40 PARKER
               IRVINE, CALIFORNIA  92718

DATED AS OF: DECEMBER 3, 1997

     THIS AMENDMENT TO LOAN AGREEMENT is entered into between SILICON VALLEY
BANK ("Silicon") and the borrower named above (the "Borrower").

     The Parties agree to amend the Loan and Security Agreement between them,
dated September 18, 1991, as amended by that Extension Agreement dated August 3,
1992, by that Amendment to Loan Agreement dated October 20, 1992, by that
Amendment to Loan Agreement dated August 23, 1993, by that Amendment to Loan
Agreement dated February 10, 1994, by that Amendment to Loan Agreement dated
July 18, 1994, by that Amendment to Loan Agreement dated September 20, 1994, by
that Amendment to Loan and Security Agreement dated August 31, 1995, by that
Amendment to Loan and Security Agreement (the "October 1995 Amendment") dated
October 5, 1995, by that Amendment to Loan Agreement dated July 3, 1996, by that
Amendment to Loan and Security Agreement dated October 6, 1996 and by that
Amendment to Loan and Security Agreement dated June 10, 1997 (the "Loan
Agreement"), as follows.  (Capitalized terms used but not defined in this
Agreement, shall have the meanings set forth in the Loan Agreement.)

     1.   REVISED SCHEDULE.  The Schedule to Loan Agreement is hereby replaced
in its entirety with the Schedule to Loan Agreement as attached hereto.

     2.   FEE.  Borrower shall pay to Silicon a facility fee in the amount of
$25,000 concurrently, which shall be in addition to all interest and all other
amounts payable under the Loan Agreement, and which shall not be refundable.

     3.   REPRESENTATIONS TRUE.  Borrower represents and warrants to Silicon
that all representations and warranties set forth in the Loan Agreement, as
amended hereby, are true and correct.

     4.   GENERAL PROVISIONS.  This Amendment, the Loan Agreement, any prior
written amendments to the Loan Agreement signed by Silicon and the Borrower, and
the other written documents and agreements between Silicon and the Borrower set
forth in full all of the representations and agreements of the parties with
respect to the subject matter hereof and supersede all prior discussions,
representations, agreements and understandings between the parties with respect
to the subject hereof.  Except as herein expressly amended, all of the terms and
provisions of the Loan Agreement, as so amended, and all other documents and
agreements between Silicon and the Borrower shall continue in full force and
effect and the same are hereby ratified and confirmed.


                                         -1-
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     SILICON VALLEY BANK                                CERTIFIED RESOLUTION
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BORROWER:                               SILICON:

SYNC RESEARCH, INC.                     SILICON VALLEY BANK

BY                                      BY
  --------------------------------        --------------------------------
     PRESIDENT OR VICE PRESIDENT        TITLE
                                             -----------------------------
BY
  --------------------------------
     SECRETARY OR ASS'T SECRETARY


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