<PAGE>

SILICON VALLEY BANK

                           AMENDMENT TO LOAN AND SECURITY
                                     AGREEMENT


BORROWER:      SYNC RESEARCH, INC.
ADDRESS:       40 PARKER
               IRVINE, CALIFORNIA  92618

DATED:         APRIL 14, 1999

     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,
by that Amendment to Loan and Security Agreement dated June 10, 1997 and by
that Amendment to Loan and Security Agreement dated as of December 3, 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.   MODIFICATION TO SECTIONS 2.2 AND 2.2A.  Section 2.2 and Section
2.2A of the Loan Agreement are hereby replaced in their entirety with the
following Section 2.2 and Section 2.2A:

     "2.2  GRANT OF SECURITY INTEREST IN COLLATERAL.  The Borrower grants
     Silicon a continuing security interest in all of the Borrower's interest in
     the Collateral (as defined below in Section 2.2A) as security for all
     Obligations.

     2.2A  COLLATERAL.  The term 'Collateral' as used herein shall mean all of
     the Borrower's interest in the types of property described below, whether
     now owned or hereafter acquired, and wherever located:  (a) All accounts,
     contract rights, chattel paper, letters of credit, documents, securities,
     money, and instruments, and all other obligations now or in the future
     owing to the Borrower; (b) All inventory, goods, merchandise, materials,
     raw materials, work in process, finished goods, farm products, advertising,
     packaging and shipping materials, supplies, and all other tangible personal
     property which is held for sale or lease or furnished under contracts

                                       -1-

<PAGE>


     of service or consumed in the Borrower's business, and all warehouse
     receipts and other documents; and (c) All equipment, including without
     limitation all machinery, fixtures, trade fixtures, vehicles, furnishings,
     furniture, materials, tools, machine tools, office equipment, computers and
     peripheral devices, appliances, apparatus, parts, dies, and jigs; (d) All
     general intangibles including, but not limited to, deposit accounts,
     goodwill, names, trade names, trademarks and the goodwill of the business
     symbolized thereby, trade secrets, drawings, blueprints, customer lists,
     patents, patent applications, copyrights, security deposits, loan
     commitment fees, federal, state and local tax refunds and claims, all
     rights in all litigation presently or hereafter pending for any cause or
     claim (whether in contract, tort or otherwise), and all judgments now or
     hereafter arising therefrom, all claims of Borrower against Silicon, all
     rights to purchase or sell real or personal property, all rights as a
     licensor or licensee of any kind, all royalties, licenses, processes,
     telephone numbers, proprietary information, purchase orders, and all
     insurance policies and claims (including without limitation credit,
     liability, property and other insurance), and all other rights, privileges
     and franchises of every kind; (e) All books and records, whether stored on
     computers or otherwise maintained; and (f) All substitutions, additions and
     accessions to any of the foregoing, and all products, proceeds and
     insurance proceeds of the foregoing, and all guaranties of and security
     for the foregoing; and all books and records relating to any of the
     foregoing.  Silicon's security interest in any present or future technology
     (including patents, trade secrets, and other technology) shall be subject
     to any licenses or rights now or in the future granted by the Borrower to
     any third parties in the ordinary course of Borrower's business; provided
     that if the Borrower proposes to sell, license or grant any other rights
     with respect to any technology in a transaction that, in substance, conveys
     a major part of the economic value of that technology, Silicon shall first
     be requested to release its security interest in the same, and Silicon may
     withhold such release in its discretion."

     3.    MODIFICATION TO SECTION 3.7.  Section 3.7 of the Loan Agreement is
hereby amended in its entirety to read as follows:

     "3.7  FINANCIAL CONDITION AND STATEMENTS.  All financial statements now or
     in the future delivered to Silicon have been, and will be, prepared in
     conformity with generally accepted accounting principles and now and in the
     future will completely and accurately reflect the financial condition of
     the Borrower, at the times and for the periods therein stated.  Since the
     last date covered by any such statement, there has been no material adverse
     change in the financial condition or business of the Borrower.  The
     Borrower is now and will continue to be solvent.  The Borrower will provide
     Silicon:  (i) within 30 days after the end of each month, a monthly
     financial statement prepared by the Borrower, and a Compliance Certificate
     in such form as Silicon shall reasonably specify, signed by the Chief
     Financial Officer of the Borrower, certifying that as of the end of such
     month the Borrower was in full compliance with all of the terms and
     conditions of this Agreement, and setting forth calculations showing
     compliance with the financial covenants set forth on the Schedule and such
     other information as Silicon shall reasonably request #; and (ii) within
     120 days following the end of the Borrower's fiscal year, complete annual
     financial statements, certified by independent certified public accountants
     acceptable to Silicon and accompanied by the unqualified report thereon by
     said independent certified public accountants.   *

     # (AND SUCH INFORMATION SHALL INCLUDE WITHOUT LIMITATION BANK AND BROKERAGE
     STATEMENTS OR OTHER EVIDENCE SATISFACTORY TO SILICON REGARDING THE
     LIQUIDITY FINANCIAL COVENANT SET FORTH IN THE SCHEDULE TO THIS AGREEMENT)

                                       -2-

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     * BORROWER SHALL ALSO SUPPLY TO SILICON (i) WITHIN 5 DAYS AFTER THE EARLIER
     OF THE DATE THE REPORT 10-Q IS FILED OR IS REQUIRED TO BE FILED WITH THE
     SECURITIES AND EXCHANGE COMMISSION WITH RESPECT TO BORROWER, SUCH 10-Q
     REPORT; AND (ii) WITHIN 5 DAYS AFTER THE EARLIER OF THE DATE THE REPORT
     10-K IS FILED OR IS REQUIRED TO BE FILED WITH THE SECURITIES EXCHANGE
     COMMISSION WITH RESPECT TO BORROWER, SUCH 10-K REPORT."

     4.    MODIFICATION TO SECTION 4.5.  Section 4.5 of the Loan Agreement is
hereby deleted in its entirety and replaced with the following:

     "4.5  ACCESS TO COLLATERAL, BOOKS AND RECORDS.  At all reasonable times,
     and upon one business day notice, Silicon, or its agents, shall have the
     right to inspect the Collateral, and the right to audit and copy the
     Borrower's accounting books and records and Borrower's books and records
     relating to the Collateral.  Silicon shall take reasonable steps to keep
     confidential all information obtained in any such inspection or audit, but
     Silicon shall have the right to disclose any such information to its
     auditors, regulatory agencies, and attorneys, and pursuant to any subpoena
     or other legal process.  The foregoing audits shall be at Silicon's
     expense, except that the Borrower shall reimburse Silicon for its
     reasonable out of pocket costs for semi-annual accounts receivable audits
     by third parties retained by Silicon, and Silicon may debit Borrower's
     deposit accounts with Silicon for the cost of such semi-annual accounts
     receivable audits (in which event Silicon shall send notification thereof
     to the Borrower).  Notwithstanding the foregoing, after the occurrence of
     an Event of Default all audits shall be at the Borrower's expense."

     5.    FEE.  Borrower shall pay to Silicon a facility fee in the amount
of $15,000 concurrently, which shall be in addition to all interest and all
other amounts payable under the Loan Agreement, and which shall not be
refundable.

     6.    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.

     7.    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.

BORROWER:                              SILICON:

SYNC RESEARCH, INC.                    SILICON VALLEY BANK

BY  /S/ RICHARD MARTIN                 BY  /S/ MARLA JOHNSON
   -----------------------------         -----------------------------
    PRESIDENT OR VICE PRESIDENT        TITLE   VICE PRESIDENT

BY  /S/ WILLIAM K. GUERRY
   -----------------------------
    SECRETARY OR ASS'T SECRETARY


                                       -3-



<PAGE>

SILICON VALLEY BANK

                               AMENDED SCHEDULE TO

                           LOAN AND SECURITY AGREEMENT

BORROWER:         SYNC RESEARCH, INC.
ADDRESS:          40 PARKER
                  IRVINE, CALIFORNIA  92618

DATED:            APRIL 14, 1999


CREDIT LIMIT
(Section 1.1):             An amount not to exceed (i) $3,000,000 at any one
                           time outstanding or (ii) 80% 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.

INTEREST RATE
(Section 1.2):             A rate equal to the "Prime Rate" in effect from time
                           to time plus .50%, 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.

                                       -1-

<PAGE>


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

MATURITY DATE
(Section 5.1):             APRIL 14, 2000

PRIOR NAMES OF BORROWER
(Section 3.2):             TYLINK CORPORATION

TRADE NAMES OF BORROWER
(Section 3.2):             NONE


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

MATERIAL ADVERSE
LITIGATION (Section 3.10): AS SET FORTH IN THE BORROWER'S DECEMBER 31, 1998 10-K
                           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 employee stock option plans or
                           other similar plans in an amount not to exceed
                           $75,000 during any fiscal year of the Borrower and
                           (ii) repurchase up to 500,000 shares of the
                           Borrower's stock during the term of this Agreement in
                           accordance with previously announced Borrower plans
                           as disclosed to Silicon.


FINANCIAL COVENANTS
(Section 4.1):             Borrower shall comply with all of the following
                           covenants. Compliance shall be determined as of the
                           end of each month, except as otherwise specifically
                           provided below:

  LIQUIDITY COVENANT       Borrower shall maintain cash on hand, cash
                           equivalents and marketable securities in an amount
                           not less than $9,000,000, with the understanding that
                           at least $3,000,000 thereof shall be on deposit with
                           Silicon at all times.

  DEBT TO TANGIBLE
  NET WORTH RATIO:         Borrower shall maintain a ratio of total liabilities
                           to tangible net worth of not more than 1.00 to 1.

  PROFITABILITY:           Borrower shall not incur a loss (after taxes) for the
                           fiscal quarter ending March 31, 1999 in excess of
                           $3,000,000; Borrower shall not incur a loss (after
                           taxes) for the fiscal quarter ending June 30, 1999 in
                           excess of $1,500,000; Borrower shall not incur a loss
                           (after taxes) for the fiscal quarter ending September
                           30, 1999 in excess of $500,000; and, thereafter,
                           Borrower shall not incur a loss (after taxes) in any



                                       -2-
<PAGE>


                           fiscal quarter. It is understood and agreed that net
                           losses through the quarter end period of September
                           30, 1999 may be cumulative.

  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.
                           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. MATERIAL ADVERSE CHANGE EVENT OF DEFAULT. Without
                           limitation of the terms and conditions of the Loan
                           Agreement, the occurrence of a material adverse
                           change in the business, operations, or condition
                           (financial or otherwise) of the Borrower, or (ii) a
                           material impairment of the prospect of repayment of
                           any portion of the Obligations or (iii) a material
                           impairment of the value or priority of Silicon's
                           security interests in the Collateral shall constitute
                           an Event of Default under this Agreement.



                                       -3-
<PAGE>


                                        BORROWER:

                                               SYNC RESEARCH, INC.


                                               BY /s/ RICHARD MARTIN
                                                 -------------------------------
                                                 President or Vice President

                                               BY /s/ WILLIAM K. GUERRY
                                                 -------------------------------
                                                  Secretary or Ass't Secretary

                                        SILICON:

                                               SILICON VALLEY BANK


                                               BY /s/ MARLA JOHNSON
                                                 -------------------------------
                                               TITLE Vice President
                                                    ----------------------------


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