<PAGE>

                             STANDBY TERM LOAN NOTE


$30,000,000.00                                                     JUNE 30, 2000


      FOR VALUE RECEIVED, the undersigned, STAR TELECOMMUNICATIONS, INC., a
Delaware corporation (the "Maker") promises to pay to the order of MCI WORLDCOM
NETWORK SERVICES, INC., a Delaware corporation with a place of business located
at 6929 North Lacewood Avenue, M.D. 5.2-510, Tulsa, Oklahoma 74117 ("Holder"),
the principal sum of the lesser of: (a) THIRTY MILLION DOLLARS ($30,000,000.00);
or (b) the aggregate principal amount of the Advances, as defined below, made by
Holder to Maker pursuant to this Standby Term Loan Note (the "Term Note"),
together with interest on the unpaid principal amount of this Term Note,
accruing at a rate of eighteen percent (18%) PER ANNUM, based on a year of 365
or 366 days, as the case may be, and actual days elapsed, on or before the
earlier to occur of (such date being referred to herein as the "Maturity Date"):
(a) termination of the Agreement and Plan of Merger dated February 11, 2000, as
amended by that certain First Amendment to Agreement and Plan of Merger, each by
and between Maker, STI Merger Co. And World Access, Inc. (the "Merger
Agreement"); (b) consummation of the merger transaction contemplated by the
Merger Agreement; or (c) August 1, 2000, without notice, demand or presentment.
Maker shall make principal and interest payments to Holder on the outstanding
obligations evidenced hereby pursuant to the terms hereof. Maker may request
Holder to extend the Maturity Date, in writing, which request shall be reviewed
by Holder, and shall be granted, denied or modified in Holder's sole and
absolute discretion. Notwithstanding the face amount of this Term Note, the
inclusion of potential Advance Dates, as defined below, beyond August 1, 2000,
nor any other provision of this Term Note, nothing herein shall be considered or
construed to be an agreement by Holder to extend the Maturity Date beyond August
1, 2000, or to make any Advances, as defined below, to Maker on the Maturity
Date, or any date after the Maturity Date.

      PROVIDED THAT, there are no Events of Default, as defined below,
hereunder, on each of (a) July 1, 2000, (b) August 1, 2000, only if Holder, in
its sole and absolute discretion, has previously agreed, in writing, to extend
the Maturity Date beyond August 1, 2000; and (c) September 1, 2000, only if
Holder, in its sole and absolute discretion, has previously agreed, in writing,
to extend the Maturity Date beyond September 1, 2000 (each, an "Advance Date"),
Maker shall be deemed to have made, and Holder shall be deemed to have received,
an advance under this Term Note (each, an "Advance"), in an amount which is the
lesser of: (a) $10,000,000; or (b) the aggregate amounts set forth on the
invoices from Holder dated as of the applicable Advance Date relative to the
aggregate usage and other charges due by the Debtor Entities (as that term is
defined in the Workout Agreement between Maker and Holder dated as of April 12,
2000, as amended (the "Workout Agreement")) to Holder pursuant to the Service
Agreements, as defined in the Workout Agreement. Undefined capitalized terms
used herein shall have the meanings ascribed to such terms in the Workout
Agreement, unless the context clearly requires otherwise. In no event shall
Maker be discharged, nor shall Holder waive or release any Debtor Entity, from
the Debtor Entities' obligations to make immediate payment to Holder of any sums
due Holder under the Service

                                        1

<PAGE>



Agreements in excess of $10,000,000 which is due or invoiced on any Advance
Date. Except as specifically set forth in this paragraph, Maker shall not be
entitled to any advances under this Term Note. Maker acknowledges that each
Advance made hereunder is and shall be considered, for all purposes, as
"additional financing provided to STAR or its Subsidiaries by MCI WorldCom
Network Services, Inc., or any of its affiliates", as contemplated by Section
5.15 of the Merger Agreement.

      Maker shall be permitted to make voluntary prepayments of principal under
this Term Note, without penalty on any date prior to the Maturity Date. Under no
circumstances shall any voluntary prepayment or prepayments entitle Maker to
further or additional credit from Holder, or to any additional Advances from
Holder. The acceptance by Holder of any payment hereunder that is less than
payment in full of all amounts due and payable shall not constitute a waiver of
the right to exercise any of Holder's rights and remedies hereunder at that
time, or at any subsequent time, or nullify any prior exercise of any such right
or remedy without the express written consent of Holder.

      All payments and prepayments to be made in respect of principal, interest
or other amounts due from the Maker under this Term Note shall be payable on or
before 12:00 noon, Tulsa time, on the Maturity Date, and shall be payable to
Holder at the address set forth above for Holder, and directed to the attention
of Robert S. Vetera, Vice President of Corporate Credit, or at such other place
as Holder may designate in writing, in lawful money of the United States of
America in immediately available funds without setoff, counterclaim or other
deduction of any nature. The Maker expressly waives presentment, demand, notice,
protest and all other demands and notices in connection with the delivery,
acceptance, performance, default or enforcement of this Term Note, and an action
for any amounts due and unpaid shall therefore accrue immediately.

      If any payment of principal or interest under this Term Note becomes due
on a day which is a Saturday, Sunday or other day on which lending institutions
are authorized or obligated to close in Tulsa, Oklahoma, such payment shall be
made on the next following business day on which such lending institutions are
open for business and such extension of time will be included in computing
interest in connection with such payment.

      All notices and other communications required or permitted to be made to
the Maker or Holder, as the case may be, hereunder shall be made in writing and
will be deemed delivered when received by the other party by messenger, telex,
telecopier, overnight courier, or mail, which notice shall be delivered to the
respective addresses of Maker and Holder, as the case may be, set forth in the
Workout Agreement, or such other address as each party may notify the other
party in writing from time to time.

      Upon the occurrence of any one of the following events (each an "Event of
Default"), the entire principal amount outstanding hereunder together with
accrued interest, shall (i) at the option of Holder in the case of the "Events
of Default" set forth in (a) through (c), below, or (ii) without the necessity
for any demand, notice or action by Holder in the case of the "Events of
Default" set forth in (d) through (e), below, become immediately due and payable
in full and Holder may, without further delay, undertake any one or more of the
actions and become entitled to any of

                                        2

<PAGE>


the remedies specified in this Term Note or any other WorldCom Document, as
defined below, or which are otherwise available at law or in equity:

      (a)   Failure of Maker to pay any installment of principal or interest or
any other sum on the date when it is due under this Term Note or the Note; or

      (b)   Maker fails to perform or observe any of its other covenants or
agreements under this Term Note or any other WorldCom Document, and any
amendments, extensions, renewals or replacements to or of any of the foregoing,
whether presently existing or hereafter arising (collectively, the "WorldCom
Documents"), and such default continues beyond any applicable grace, waiver or
cure period set forth therein, if any; or

      (c)   Any material representation or warranty made by the Maker pursuant
to this Term Note or any other WorldCom Document shall prove to have been false
or misleading in any material respect as of the time when made; or

      (d)   If Maker, or any Guarantor shall make a general assignment for the
benefit of its respective creditors, or shall admit in writing its inability to
pay its debts as they become due, or shall file a petition in bankruptcy, or
shall be adjudicated bankrupt or insolvent, or shall file a petition seeking any
relief under any present or future statute, law or regulation relating to
bankruptcy or insolvency or shall file an answer admitting or not contesting the
material allegations of a petition filed against it in any such proceeding or
shall seek or consent to or acquiesce in the appointment of any trustee or
receiver of itself or any material part of its respective properties; or

      (e)   If any proceeding against Maker seeking any relief under any present
or future statute, law or regulation relating to bankruptcy or insolvency shall
have been filed or shall be prosecuted or if an appointment shall have been made
without the consent or acquiescence of Maker or of any material part of their
respective properties and such appointment shall not have been vacated; or

      If an Event of Default occurs, then, Maker agrees to indemnify and hold
Holder harmless from any and all reasonable fees and expenses of Holder's
attorneys, accountants, appraisers, consultants, engineers and other
professional, paraprofessional or non-professional fees and expenses incurred by
Holder in collecting the obligations evidenced hereby, or in protecting or
otherwise enforcing any of its rights under this Term Note or any of the other
WorldCom Documents, or in the prosecution or defense of any action related to
this Term Note or any of the WorldCom Documents, or the preservation,
maintenance, disposition or liquidation of any collateral securing the Maker's
obligations evidenced by this Term Note, or any portion thereof.

      The exercise of any remedy hereunder or under any other WorldCom Document
shall not be construed as a waiver by Holder of any remedy available to Holder
under any other agreement, document, or applicable law. Holder hereby expressly
reserves all of its rights under applicable law.


                                        3

<PAGE>


      In the event the rate of interest provided for in this Term Note is
finally determined by any government or political subdivision or any agency,
authority, bureau, central bank, commission, department or instrumentality of
either, or any court, tribunal, grand jury or arbitrator, in each case whether
foreign or domestic (each as "Official Body"), to exceed the maximum rate of
interest permitted by applicable usury or similar law (including common law),
constitution, statute, treaty, regulation, rule, ordinance, order, injunction,
writ, decree or award of any Official Body ("Law"), their or its application
will be suspended and there will be charged instead the maximum rate of interest
permitted by such Laws. Interest at the rates applicable to the Term Note as set
forth herein shall continue to accrue on any judgment entered on this Term Note
until the judgment together with interest and costs has been paid in full.

      This Term Note is governed by, and will be construed and enforced in
accordance with, the laws of the State of Oklahoma without regard to principles
of conflicts of law in the State of Oklahoma. The Maker consents to the
exclusive jurisdiction and venue of the Federal and State courts located in
Tulsa, Oklahoma with respect to any suit arising out of, relating to, or
mentioning this Term Note. The terms of this Term Note shall be binding upon and
inure to the benefit of the successors and assigns of Holder, and shall not be
assignable by Maker, unless Holder has provided its prior, written consent to
such assignment.

EACH OF MAKER AND HOLDER EXPRESSLY, KNOWINGLY AND VOLUNTARILY
WAIVES ALL BENEFIT AND ADVANTAGE OF ANY RIGHT TO A TRIAL BY JURY, AND NEITHER
WILL AT ANY TIME INSIST UPON, OR PLEAD OR IN ANY MANNER WHATSOEVER CLAIM OR TAKE
THE BENEFIT OR ADVANTAGE OF A TRIAL BY JURY IN ANY ACTION ARISING IN CONNECTION
HEREWITH OR THE OTHER WORLDCOM DOCUMENTS.

INITIAL:       ____  MAKER


               ____  HOLDER

      IN WITNESS WHEREOF, and intending to be legally bound, the Maker has
executed, issued and delivered this Standby Term Loan Note as of the day and
year first above written.

ATTEST:                                STAR TELECOMMUNICATIONS, INC.

By:                                    By:
   -------------------------------        -------------------------------
Name:                                  Name:
     -----------------------------          -----------------------------
Title:                                 Title:
      ----------------------------           ----------------------------



                                       4