REGISTRATION RIGHTS AGREEMENT

          THIS REGISTRATION RIGHTS AGREEMENT (this "AGREEMENT"), dated February
3, 1999, is made and entered into by and among Communication Telesystems
International d.b.a. WorldxChange Communications, a California corporation (the
"COMPANY"), and Atocha, L.P. ("ATOCHA").

                                       RECITALS

          WHEREAS, the Company and Atocha are parties to that certain Stock
Purchase Agreement, dated February 3, 1999 (the "PURCHASE AGREEMENT"), which
provides for Atocha's purchase from the Company of an aggregate of 3,000,000
shares of the Common Stock of the Company (with 1,500,000 of such shares (the
"INITIAL SHARES") to be purchased at the Initial Closing (as defined in the
Purchase Agreement) and 1,500,000 shares (the "REMAINING SHARES") to be
purchased at the Second Closing (as defined in the Purchase Agreement)); and

          WHEREAS, in order to induce Atocha to enter into the Purchase
Agreement, the Company has agreed to provide the registration rights set forth
in this Agreement with respect to the "REGISTRABLE SECURITIES" (as such term is
defined in Section 1).

          NOW, THEREFORE, in consideration of the foregoing premises and the
mutual covenants and agreements herein contained, the parties, intending to be
legally bound, hereby agree as follows:

          1. DEFINITIONS. FOR PURPOSES OF THIS AGREEMENT:

               (a)  the term "BONA FIDE PUBLIC OFFERING" means an underwritten
     public offering pursuant to an effective registration statement under the
     Securities Act of 1933, as amended (the "1933 ACT"), covering the offer and
     sale of Common Stock of the Company in which aggregate proceeds to the
     Company and the selling shareholders exceed $25,000,000;

               (b)  the term "COMMON STOCK" means the Company's authorized
     voting common stock, no par value, and any class of securities issued in
     exchange for the Common Stock or into which the Common Stock is converted;

               (c)  the term "HOLDER" means Atocha or any permitted transferee
     of Registrable Securities pursuant to the Purchase Agreement in accordance
     with Section 10 hereof;

               (d)  the term "INITIATING HOLDERS" means the Holders of 30% or
     more of the Registrable Securities then outstanding;



               (e)  the term "ORIGINAL REGISTRATION RIGHTS AGREEMENT" means that
     certain Registration Rights Agreement effective as of September 30, 1998 by
     and among the Company, Atocha and the other investors named therein.

               (f)  the term "REGISTRABLE SECURITIES" means: (i) if acquired by
     Atocha pursuant to the Purchase Agreement, the Initial Shares; (ii) if
     acquired by Atocha pursuant to the Purchase Agreement, the Remaining
     Shares; and (iii) any Common Stock of the Company issued as (or issuable
     upon the conversion or exercise of any warrant, right or other security
     which is issued as) a dividend or other distribution with respect to, or in
     exchange for or in replacement of such Initial Shares and/or Remaining
     Shares;

               (g)  the term "REGISTRATION EXPENSES" means all expenses incurred
     by the Company in complying with Sections 2 and 3 hereof, including,
     without limitation, all registration and filing fees, printing expenses,
     fees and disbursements of counsel for the Company, accountants' fees and
     expenses, and blue sky fees and expenses;

               (h)  the terms "REGISTER," "REGISTERED" and "REGISTRATION" refer
     to a registration effected by preparing and filing a registration statement
     or similar document in compliance with the 1933 Act, and the declaration or
     ordering of the effectiveness of such registration statement or document by
     the Securities and Exchange Commission;

               (i)  the term "SELLING EXPENSES" means all underwriting discounts
     and selling commissions applicable to the sale of Registrable Securities,
     the fees and disbursements of any counsel engaged by the Holders and any
     other expenses incurred by the Holders in connection with the registration
     and sale of the Registrable Securities;

               (j)  the number of shares of Registrable Securities "THEN
     OUTSTANDING" shall be the number of shares of Common Stock outstanding
     which are, and the number of shares of Common Stock which upon issuance of
     then exercisable or convertible securities will be, Registrable Securities;
     and

               (k)  the term "THIRD PARTY HOLDER" means (A) any person other
     than a Holder with registration rights with respect to securities of the
     Company and (B) Atocha (or any permitted transferee of Atocha) with respect
     to securities of the Company as to which Atocha (or any such transferee of
     Atocha) has registration rights pursuant to the Original Registration
     Rights Agreement.

          2. DEMAND REGISTRATION RIGHTS.

               (a)  If the Company shall receive, at any time during the one-
     year period commencing three years after the date of this Agreement (and in
     such additional years as may be required by Section 2(d)), a written
     request from the Initiating Holders with respect to the Registrable
     Securities that the Company file a registration statement under the 1933
     Act covering the registration of


                                          2



     Registrable Securities having an estimated aggregate initial public
     offering price of not less than $5,000,000, provided that a Bona Fide
     Public Offering has not been commenced by the Company, the Company shall
     promptly give written notice of such request to all Holders and shall use
     reasonable efforts to effect the registration under the 1933 Act of all
     such Registrable Securities which the Initiating Holders request to be
     registered, together with all of the Registrable Securities of any other
     Holder or Holders who so request by notice to the Company which is given
     within 10 days after receipt of the notice from the Company described
     above. Notwithstanding the foregoing, if the Company shall furnish to the
     Initiating Holders a certificate signed by the President of the Company
     stating that in the good faith judgment of the Board of Directors it would
     be seriously detrimental to the Company for a registration statement to be
     filed in the near future, then the Company's obligation to use its
     reasonable efforts to file a registration statement shall be deferred for a
     period not to exceed 90 days (provided, however, that the Company may make
     only one such deferral with respect to each demand registration).
     Securities of the Company to be sold by the Company or by a Third Party
     Holder may be included in such registration statement, subject to the
     provisions of Section 2(c) below.

               (b)  If the Initiating Holders intend to distribute the
     Registrable Securities covered by their request by means of an
     underwriting, they shall so advise the Company as a part of their request
     made pursuant to this Section 2 and the Company shall include such
     information in the written notice referred to in Section 2(a). In such
     event, the right of any Holder to include its Registrable Securities in
     such registration shall be conditioned upon such Holder's participation in
     such underwriting and the inclusion of such Holder's Registrable Securities
     in the underwriting (unless otherwise mutually agreed by a majority in
     interest of the Initiating Holders, by the underwriter, by the Company, and
     by such Holder) to the extent provided herein.

               (c)  All Holders and Third Party Holders proposing to distribute
     their securities through such underwriting (together with the Company as
     provided in Section 4(e)) shall enter into an underwriting agreement in
     customary form with the representative of the underwriter or underwriters
     selected for such underwriting by the Company, or if no underwriter is
     selected by the Company, by a majority in interest of the Initiating
     Holders and reasonably acceptable to the Company. Notwithstanding any other
     provisions of this Section 2, if the underwriter advises the Initiating
     Holders in writing that marketing factors require a limitation of the
     number of shares to be underwritten, the Initiating Holders shall so advise
     all Holders of Registrable Securities, and the number of shares of
     Registrable Securities that may be included in the registration and
     underwriting by the Holders shall be allocated among all Holders thereof,
     all Third Party Holders, and the Company, pro rata based on the number of
     shares for which registration was requested. No Registrable Securities
     excluded from the underwriting by reason of the marketing limitation shall
     be included in such registration. If any Holder of Registrable Securities
     disapproves of the terms of the underwriting, such person may elect to
     withdraw therefrom by written notice


                                          3



     to the Company, the underwriter and, unless otherwise provided, the
     Initiating Holders.

               (d)  The Company is obligated to effect only one demand
     registration for the Holders pursuant to this Section 2; provided, however,
     that if any Registrable Securities of a Holder requested to be registered
     (regardless of whether a Holder withdraws such Registrable Securities
     pursuant to Section 2(c) or Section 6) are excluded by the underwriter in a
     demand registration pursuant to Section 2(c) or in a "piggyback"
     registration pursuant to Section 6 (which excluded Registrable Securities
     are referred to herein as the "EXCLUDED SECURITIES"), then the Company,
     upon the demand of the Initiating Holders three or more years after the
     date of this Agreement, shall be obligated to effect one additional demand
     registration under this Section 2 each year with respect to the Excluded
     Securities of such Holder, until such time as (i) such Holder may freely
     (except as may be restricted by Rule 144 under the 1933 Act) sell all of
     the Excluded Securities without registration under the 1933 Act within the
     then following six months and (ii) the Excluded Securities are listed on a
     securities exchange or qualified for trading on an over-the-counter system
     selected by the Company.

               (e)  The demand registration rights provided by the Company to
     any Holder pursuant to Section 2 of this Agreement shall immediately
     terminate upon the closing of a Bona Fide Public Offering by the Company.

               (f)  A registration requested pursuant to this Section 2 shall
     not be deemed to have been effected (a) unless a registration statement
     with respect thereto has become effective or (b) if after it has become
     effective, the effectiveness of such registration statement is terminated
     or suspended by a stop order, injunction or other order of the SEC or other
     governmental agency or court, unless such order, injunction or other order
     is lifted or stayed within 30 days of the issuance of such stop order,
     injunction or other order. The Company shall use its reasonable best
     efforts to keep such registration statement effective for up to 60 days
     after such registration statement has become effective.

          3. PIGGY-BACK REGISTRATION RIGHTS. If at any time the Company proposes
to register (including for this purpose a registration effected by the Company
for shareholders other than the Holders) any of its securities under the 1933
Act in connection with the public offering of such securities solely for cash
(other than a registration form relating to: (a) a registration of a stock
option, stock purchase or compensation or incentive plan or of stock issued or
issuable pursuant to any such plan, or a dividend investment plan; (b) a
registration of securities proposed to be issued in exchange for securities or
assets of, or in connection with a merger or consolidation with, another
corporation; or (c) a registration of securities proposed to be issued in
exchange for other securities of the Company), the Company shall, each such
time, promptly give each Holder written notice of such registration together
with a list of the jurisdictions in which the Company intends to attempt to
qualify such securities under applicable state securities laws. Upon the written
request of any Holder given within 30 days after receipt


                                          4



of such written notice from the Company in accordance with Section 14, the
Company shall (subject to the provisions of Section 6 in the case of an
underwritten offering) cause to be registered under the 1933 Act all of the
Registrable Securities that each such Holder has requested to be registered;
provided, however, in the event and to the extent such a Holder may freely
(except as may be restricted by Rule 144 under the 1933 Act) sell all of its
Registrable Securities without registration under the 1933 Act and the person
acquiring the securities does not acquire "restricted securities" within the
meaning of Rule 144, the Company may elect not to register such Registrable
Securities.

          4. OBLIGATIONS OF THE COMPANY. Whenever required under this Agreement
to effect the registration of any Registrable Securities, the Company shall, as
expeditiously as reasonably possible:

               (a)  Prepare and file with the Securities and Exchange Commission
     ("SEC") a registration statement with respect to such Registrable
     Securities and use its best efforts to cause such registration statement to
     become effective;

               (b)  Prepare and file with the SEC such amendments and
     supplements to such registration statement and the prospectus used in
     connection with such registration statement as may be necessary to comply
     with the provisions of the 1933 Act with respect to the disposition of all
     securities covered by such registration statement;

               (c)  Furnish to the Holders such numbers of copies of a
     prospectus, including a preliminary prospectus, in conformity with the
     requirements of the 1933 Act, and such other documents as they may
     reasonably request in order to facilitate the disposition of Registrable
     Securities owned by them;

               (d)  Use its best efforts to register and qualify the securities
     covered by such registration statement under the securities laws of such
     jurisdictions as shall be necessary for the distribution of the securities
     covered by the registration statement and such jurisdictions as the Holders
     participating in the offering shall reasonably request, provided that the
     Company shall not be required in connection therewith or as a condition
     thereto to qualify to do business or to file a general consent to service
     of process in any such jurisdiction, and further provided that (anything in
     this Agreement to the contrary notwithstanding with respect to the bearing
     of expenses) if any jurisdiction in which the securities shall be qualified
     shall require that expenses incurred in connection with the qualification
     of the securities in that jurisdiction be borne by selling shareholders,
     such expenses shall be payable by the selling Holders pro rata, to the
     extent required by such jurisdiction;

               (e) In the event of any underwritten public offering, enter into
     and perform its obligations under an under writing agreement with
     commercially reasonable and customary terms generally satisfactory to the
     managing


                                          5



     underwriter of such offering. Each Holder participating in such
     underwriting shall also enter into and perform its obligations under such
     an agreement; and

               (f)  Use its reasonable best efforts to cause all such
     Registrable Securities to be listed on a securities exchange or to qualify
     such Registrable Securities for trading on an over-the-counter system
     selected by the Company;

               (g)  Provide a transfer agent and registrar for all such
     Registrable Securities not later than the effective date of such
     registration statement and thereafter maintain such a transfer agent and
     registrar;

               (h)  In the event of any underwritten public offering, make
     available for inspection, at reasonable times during normal business hours,
     by any underwriter participating in such public offering and any attorney,
     accountant or other agent retained by such underwriter, such financial and
     other records, pertinent corporate documents and properties of the Company
     as may be reasonably requested by such underwriter, and cause the Company's
     officers, directors, employees and independent accountants to supply such
     information as may be reasonably requested by any such underwriter,
     attorney, accountant or agent in connection with such public offering
     (provided, however, that such inspection and supplying of records and
     documents shall be subject to the execution by each requesting party of a
     confidentiality and non-disclosure agreement in a form reasonably
     acceptable to the Company);

               (i)  Permit any Holder participating in such registration, which
     Holder, in such Holder's reasonable judgment, might be deemed to be an
     underwriter or controlling person of the Company, to participate in the
     preparation of the registration statement in connection with such
     registration and to propose the insertion therein of material which in the
     reasonable judgment of such Holder and its counsel should be included;

               (j)  In connection with underwritten offerings, make available
     appropriate management personnel for participation in the preparation and
     drafting of such registration or comparable statement, for due diligence
     meetings and for "road show" meetings;

               (k)  In the event of the issuance of any stop order suspending
     the effectiveness of a registration statement, or of any order suspending
     or preventing the use of any related prospectus or suspending the
     qualification of any Registrable Securities included in such registration
     statement for sale in any jurisdiction, the Company will use its reasonable
     best efforts promptly to obtain the withdrawal of such order, provided that
     in the Company's opinion, in consultation with its counsel, there is a good
     faith argument for the removal of such order;

               (l)  Obtain a cold comfort letter from the Company's independent
     public accountants addressed to the selling Holders of Registrable



                                          6



     Securities in customary form and covering such matters of the type
     customarily covered by cold comfort letters as the Holders of a majority of
     the Registrable Securities being sold reasonably request; and

               (m)  Furnish, at the request of Holders of a majority of the
     Registrable Securities participating in the registration, to each seller of
     Registrable Securities a signed counterpart, addressed to such seller (and
     underwriters, if any) of an opinion of counsel for the Company, dated the
     effective date of such registration statement (or, if such registration
     includes an underwritten public offering, dated the date of the closing
     under the underwriting agreement), reasonably satisfactory in form and
     substance to such Holder covering substantially the same matters with
     respect to such registration (and the prospectus included therein) as are
     customarily covered in opinions of issuer's counsel to underwriters in
     underwritten public offerings.

          5. FURNISH INFORMATION. It shall be a condition precedent to the
obligations of the Company to take any action pursuant to this Agreement that
the selling Holders shall furnish to the Company such information regarding
themselves, the Registrable Securities held by them, and the intended method of
disposition of such securities as shall be required to effect the registration
of their Registrable Securities. In that connection, each selling Holder shall
be required to represent to the Company that all such information which is given
is both complete and accurate in all material respects.

          6. UNDERWRITING REQUIREMENTS. The right of any Holder to "piggyback"
in an underwritten public offering of the Company's securities pursuant to
Section 3 shall be conditioned upon such Holder's participation in such
underwriting and the inclusion of such Holder's Registrable Securities in the
underwriting to the extent provided herein. All Holders proposing to distribute
their securities through such underwriting shall (together with the Company and
any other holders distributing their securities through such underwriting) enter
into an underwriting agreement in customary form with the underwriter or
underwriters selected for underwriting by the Company. Notwithstanding any other
provision of Section 3 and this Section 6, if the underwriter determines that
marketing factors require a limitation of the number of shares to be
underwritten, and (a) if such registration is the first registered offering of
the Company's securities to the public, the underwriter may exclude some or all
of the Registrable Securities from such registration and underwriting, provided
that the Holders are allowed to participate in the offering in the same
proportion (based on the total number of securities requested to be registered)
as any other shareholder of the Company participating in the offering, and (b)
if such registration is other than the first registered offering of the
Company's securities to the public, the underwriter may exclude some or all
Registrable Securities from such registration and underwriting, provided that
all of the shares requested to be registered by shareholders other than Holders
and Third Party Holders shall first be excluded and thereafter, only to the
extent deemed necessary by the underwriter, shares requested to be registered by
Holders and Third Party Holders shall be reduced pro rata based on the number of
securities respectively requested by them to be registered. Any reduction in the
number of Registrable Securities included in such registration shall be borne
equally by the Holders and any Third Party Holders as a group


                                          7



pro rata based on the number of shares for which registration was requested. If
any Holder disapproves of the terms of any such underwriting, it may elect to
withdraw therefrom by written notice to the Company and the underwriter. Any
Registrable Securities excluded or withdrawn from such underwriting shall be
withdrawn from such registration. Third Party Holders "piggybacking" on a demand
registration demanded by the Initiating Holders under Section 2 above shall be
subject to the same conditions, requirements and limitations that are applicable
to a Holder under this Section 6 in the event of an underwritten public
offering.

          7. EXPENSES OF REGISTRATION. All Registration Expenses incurred in
connection with any registration, qualification or compliance pursuant to this
Agreement shall be borne by the Company, and all Selling Expenses shall be borne
by the Holders of the securities so registered pro rata on the basis of the
number of shares so registered.

          8. DELAY OF REGISTRATION. No Holder shall have any right to obtain or
seek an injunction restraining or otherwise delaying any registration as the
result of any controversy that might arise with respect to the interpretation or
implementation of this Agreement.

          9. INDEMNIFICATION. If any Registrable Securities are included in a
registration statement under this Agreement:

               (a)  To the extent permitted by law, the Company will indemnify
     and hold harmless each Holder, the officers, directors and partners of each
     Holder, any underwriter (as defined in the 1933 Act) for such Holder and
     each person, if any, who controls such Holder or underwriter within the
     meaning of the 1933 Act or the Securities Exchange Act of 1934, as amended
     (the "1934 ACT"), against any losses, claims, damages, or liabilities
     (joint or several) to which they or any of them may become subject under
     the 1933 Act, the 1934 Act or any other federal or state law, insofar as
     such losses, claims, damages, or liabilities (or actions in respect
     thereof) arise from or are based upon any of the following statements,
     omissions or violations (collectively a "VIOLATION"): (i) any untrue
     statement or alleged untrue statement of a material fact contained in such
     registration statement, including any preliminary prospectus or final
     prospectus contained therein or any amendments or supplements thereto; or
     (ii) the omission or alleged omission to state therein a material fact
     required to be stated therein, or necessary to make the statements therein
     not misleading; and the Company will reimburse each such Holder, officer,
     director or partner, underwriter or controlling person for any legal or
     other expenses reasonably incurred by them in connection with investigating
     or defending any such loss, claim, damage, liability, or action; provided,
     however, that the indemnity agreement contained in this Section 9 shall not
     apply to amounts paid in settlement of any such loss, claim, damage,
     liability or action if such settlement is effected without the consent of
     the Company (which consent shall not be unreasonably withheld), nor shall
     the Company be liable in any such case for any such loss, claim, damage,
     liability, or action to the extent that it arises from or is based upon a
     violation which occurs in reliance upon and in conformity with written
     information furnished expressly for


                                          8



     use in connection with such registration by any such Holder, underwriter or
     controlling person.

               (b)  To the extent permitted by law, each selling Holder will
     indemnify and hold harmless the Company, each of its directors, each of its
     officers who have signed the registration statement, each person, if any,
     who controls the Company within the meaning of the 1933 Act, any
     underwriter (within the meaning of the 1933 Act) for the Company, any
     person who controls such underwriter, any other Holder selling securities
     in such registration statement or any of its directors or officers or any
     person who controls such Holder against any losses, claims, damages or
     liabilities (joint or several) to which the Company or any such director,
     officer, controlling person, or underwriter or other such Holder or
     director, officer or controlling person may become subject, under the 1933
     Act, the 1934 Act or any other federal or state law, insofar as such
     losses, claims, damages, or liabilities (or actions in respect thereto)
     arise from or are based upon any Violation, in each case to the extent (and
     only to the extent) that such Violation occurs in reliance upon and in
     conformity with written information furnished by such Holder expressly for
     use in connection with such registration; and each such Holder will
     reimburse any legal or other expenses reasonably incurred by the Company or
     any such director, officer, controlling person, underwriter or controlling
     person, other Holder, officer, director or controlling person in connection
     with investigation or defending any such loss, claim, damage, liability, or
     action; provided, however, that the indemnity agreement contained in this
     Section 9 shall not apply to amounts paid in settlement of any such loss,
     claim damage, liability or action if such settlement is effected without
     the consent of the Holder which consent shall not be unreasonably withheld.

               (c)  In order to provide for just and equitable contribution in
     circumstances in which the indemnification provided for in this Section 9
     is applicable but for any reason is held to be unavailable from the Company
     or any Holder, the Company and the Holders participating in the
     registration shall contribute to the aggregate losses, claims, damages and
     liabilities (including any investigation, legal and other expenses incurred
     in connection with, and any amount paid in settlement of, any action, suit
     or proceeding or any claims asserted) to which the Company and the
     participating Holders may be subject in such proportion so that the
     participating Holders are responsible for that portion of the foregoing
     amount represented by the ratio of the proceeds received by the
     participating Holders in the offering to the total proceeds received from
     the offering by the Company and all selling shareholders (other than
     participating Holders) and the Company shall be responsible for the portion
     represented by the ratio of proceeds received by the Company to the total
     proceeds received by the Company and all selling shareholders (other than
     participating Holders); provided, however, that such portions shall be
     adjusted as may be just and equitable to take into account the relative
     fault of the participating Holders and the Company; provided further,
     however, that no person guilty of fraudulent misrepresentation (within the
     meaning of Section 11(f) of the 1933 Act) shall be entitled to
     contribution from any person who was not guilty of such fraudulent


                                          9



     misrepresentation. For purposes of this Section 9(c), each person, if any,
     who controls the Company or any Holder within the meaning of the 1933 Act,
     each officer of the Company who shall have signed the registration
     statement and each director of the Company shall have the same rights to
     contribution as the Company.

               (d)  No settlement shall be effected without the prior written
     consent of the Holders participating in a registration unless (i) the
     obligations of the Company for indemnification or contribution pursuant to
     this Agreement survive and are not extinguished by reason of the settlement
     and remain in full force and effect under applicable federal and state
     laws, rules, regulations and orders or (ii) all claims and actions against
     the participating Holders and each person who controls a participating
     holder within the meaning of Section 15 of the 1933 Act or Section 20 of
     the 1934 Act are extinguished by the settlement and the indemnifying party
     obtains a full release of all claims and actions against the participating
     Holders and each such control person, which release shall be to the
     reasonable satisfaction of the participating Holders.

               (e)  Promptly after receipt by an indemnified party under this
     Section 9 of notice of the commencement of any action (including any
     governmental action), such indemnified party will, if a claim in respect
     thereof is to be made against any indemnifying party under this Section 9,
     notify the indemnifying party in writing of the commencement thereof and
     the indemnifying party shall have the right to participate in, and, to the
     extent the indemnifying party so desires, jointly with any other
     indemnifying party similarly noticed, to assume the defense thereof with
     counsel mutually satisfactory to the parties; provided, however, that an
     indemnified party shall have the right to retain its own counsel, with the
     fees and expenses to be paid by the indemnifying party, if representation
     of such indemnified party by the counsel retained by the indemnifying party
     would be inappropriate due to actual or potential differing interests
     between such indemnified party and any other party represented by such
     counsel in such proceeding. The failure to notify an indemnifying party
     within a reasonable time of the commencement of any such action, to the
     extent prejudicial to its ability to defend such action, shall relieve such
     indemnifying party of any liability to the indemnified party under this
     Section 9, but the omission so to notify the indemnifying party will not
     relieve it of any liability that it may have to any indemnified party
     otherwise than under this Section 9.

               (f)  The obligations of the Company and the Holders under this
     Section 9 shall survive through the completion of any offering of
     Registrable Securities in a registration statement made under the terms of
     this Agreement.

          10. ASSIGNMENT OF REGISTRATION RIGHTS. The rights of a Holder under
this Agreement may be assigned by a Holder only to a permitted transferee of
such securities pursuant to Section 6.3 of the Purchase Agreement, provided the
Company is, within a reasonable time after such transfer, furnished with written
notice of the name and address of such transferee and the securities with
respect to which such registration rights are


                                          10



being assigned; provided, however, that no such assignment shall be effective
if, immediately following the transfer, the transferee is free to dispose of all
of such securities without regard to any restrictions imposed under the 1933
Act.

          11. SUBSEQUENT REGISTRATION RIGHTS. The Company may grant registration
rights to parties other than the Holders; provided, however, that in the event
the Company shall grant any person registration rights containing terms more
favorable than the terms granted herein, the more favorable terms shall
automatically be deemed granted to the Holders and incorporated herein by
reference. Prior to the date of this Agreement, the Company has not granted
registration rights to any other person that are still in effect and that are on
terms more favorable than the terms granted herein.

          12. "MARKET STAND-OFF" AGREEMENT. Each Holder hereby agrees that it
shall not, to the extent requested by the Company and an underwriter of Common
Stock (or other securities) of the Company, sell or otherwise transfer or
dispose of any Registrable Securities in a market transaction during a period
deemed by the underwriter to be necessary or appropriate following the effective
date of a registration statement of the Company filed under the 1933 Act,
provided that Roger B. Abbott, Rosalind Abbott, and Edward S. Soren are subject
to such an agreement for the same period. In order to enforce the foregoing
covenant, the Company may impose stop-transfer instructions with respect to the
Registrable Securities of each Holder (and the shares or securities of every
other person subject to the foregoing restriction) until the end of such period.

          13. AMENDMENTS AND WAIVERS. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Company has obtained the written consent of Holders
of at least a majority of the then outstanding Registrable Securities.
Notwithstanding the foregoing, a waiver or consent to departure from the
provisions hereof with respect to a matter which relates exclusively to the
rights of Holders of Registrable Securities whose securities are being sold
pursuant to a registration statement and which does not directly or indirectly
affect the rights of other holders of Registrable Securities may be given by the
holders of a majority of the Registrable Securities being sold; provided,
however, that the provisions of this sentence may not be amended, modified or
supplemented except in accordance with the provisions of the immediately
preceding sentence.

          14. NOTICES. All notices, demands and requests required by this
Agreement shall be in writing and shall be deemed to have been given for all
purposes (a) upon personal delivery, (b) one business day after being sent, when
sent by professional overnight courier service from and to locations within the
continental United States, or (c) five days after posting when sent by
registered or certified mail (return receipt requested), addressed to the
Company or an Investor at his, her or its address set forth on the signature
pages hereof. Any party hereto may from time to time by notice in writing served
upon the others as provided herein, designate a different mailing address or a
different person to which such notices or demands are thereafter to be addressed
or delivered.


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          15. COUNTERPARTS. This Agreement may be executed in separate
counterparts, each of which shall be deemed to be an original, and when
executed, separately or together, shall constitute a single original instrument,
effective in the same manner as if the parties hereto had executed one and the
same instrument.

          16. CAPTIONS. Captions are provided herein for convenience only and
they are not to serve as a basis for interpretation or construction of this
Agreement, nor as evidence of the intention of the parties hereto.

          17. CROSS-REFERENCES. All cross-references in this Agreement, unless
specifically directed to another agreement or document, refer to provisions
within this Agreement.

          18. GOVERNING LAW.  This Agreement shall be governed by, interpreted
under, and construed and enforced in accordance with the internal laws, and not
the laws pertaining to conflicts or choice of laws, of the State of California
applicable to agreements made and to be performed wholly within the State of
California. In the event a judicial or other proceeding is necessary to resolve
any dispute hereunder, the sole forum for resolving disputes arising under or
relating to this Agreement shall be the Municipal and Superior Courts for the
County of San Diego, State of California, or the federal district court for the
district of California associated with such county and all related appellate
courts and the parties hereby consent to the jurisdiction of such courts, and
that venue shall be in such county.

          19. SEVERABILITY. The provisions of this Agreement are severable. The
invalidity, in whole or in part, of any provision of this Agreement shall not
affect the validity or enforceability of any other of its provisions. If one or
more provisions hereof shall be declared invalid or unenforceable, the remaining
provisions shall remain in full force and effect and shall be construed in the
broadest possible manner to effectuate the purposes hereof. The parties further
agree to replace such void or unenforceable provisions of this Agreement with
valid and enforceable provisions which will achieve, to the extent possible, the
economic, business and other purposes of the void or unenforceable provisions.

          20. ENTIRE AGREEMENT. This Agreement contains the entire understanding
among the parties hereto with respect to the subject matter hereof and
supersedes all prior written and oral agreements, understandings, commitments
and practices between the parties, including all prior agreements with respect
to registration rights.

          21. CONSIDERATION FOR APPROVALS OR WAIVERS. No consideration shall be
paid to any Holder to obtain such Holder's approval for or waiver of any
amendment of this Agreement or any matter requiring the approval or consent of
the Holders hereunder unless such consideration is also offered to all Holders,
pro rata based upon the number of Registerable Securities held by the Holders.

          22. REMEDIES.  Subject to Section 8 (Delay of Registration), each
Holder of Registrable Securities, in addition to being entitled to exercise all
rights granted by


                                          12



law, including recovery of damages, will be entitled to specific performance of
its rights under this Agreement.










                                          13



          IN WITNESS WHEREOF, the parties hereto have executed this
Registration Rights Agreement with the intent and agreement that the same
shall be effective as of the day and year first above written.

                                   THE COMPANY:

                                   Communication Telesystems International
                                   d.b.a. WorldxChange Communications,
                                   a California corporation

                                   By: /s/  Roger B. Abbott
                                      -------------------------------------
                                   Title:   CEO
                                         ----------------------------------

                                   Address:  9999 Willow Creek Road
                                             San Diego, California 92131
                                             Attn:  Roger B. Abbott
                                             Fax:   (619) 625-0217

ATOCHA:

ATOCHA, L.P.,
a Texas limited partnership


By: /s/ [Illegible]
   -----------------------------

Title: General Partner
      --------------------------

Address: 6429 Georgetown Pike
        ------------------------
         McLean, VA 72101
        ------------------------


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