Exhibit 3.1

                            AMENDED AND RESTATED
                        CERTIFICATE OF INCORPORATION

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                  Pursuant to Sections 242 and 245 of the
                      Delaware General Corporation Law

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         deltathree, Inc. (the "Corporation"), a corporation organized and
existing under the General Corporation Law of the State of Delaware (the
"GCL"), does hereby certify as follows:

                  (1) The name of the Corporation is deltathree, Inc. The
Corporation was previously incorporated under the name deltathree.com, Inc.
and was originally incorporated under the name RSL Acquisition Corp. The
original certificate of incorporation of the Corporation was filed with the
office of the Secretary of State of the State of Delaware on January 27,
1998. Such certificate of incorporation was amended on May 17, 1999. The
certificate of incorporation was amended and restated on September 24, 1999
and such Amended and Restated Certificate of Incorporation was then further
amended on November 19, 1999 and then again on December 11, 2000.

                  (2) This Amended and Restated Certificate of
Incorporation was duly adopted by the Board of Directors of the Corporation
(the "Board of Directors") and by the stockholders of the Corporation in
accordance with Sections 228, 242 and 245 of the GCL.

                  (3) This Amended and Restated Certificate of
Incorporation restates and integrates and further amends the certificate of
incorporation of the Corporation, as heretofore amended, restated or
supplemented.

                  (4) The text of the Certificate of Incorporation is
amended and restated in its entirety as follows:

         FIRST: The name of the Corporation is deltathree, Inc. (the
"Corporation").

         SECOND: The address of the registered office of the Corporation is
Corporation Trust Center, 1209 Orange Street, in the City of Wilmington,
County of New Castle, State of Delaware 19801. The name of its registered
agent at that address is The Corporation Trust Company.

         THIRD: The purpose of the Corporation is to engage in any lawful
act or activity for which a corporation may be organized under the General
Corporation Law of the State of Delaware (the "GCL").

         FOURTH: (a) Authorized Capital Stock. The total number of shares
of stock which the Corporation shall have authority to issue is 100,001,000
shares of capital stock, consisting of (i) 75,000,000 shares of Class A
common stock, par value $0.001 per share (the "Class A Common Stock"), (ii)
1,000 shares of Class B common stock, par value $0.001 per share (the
"Class B Common Stock") and (iii) 25,000,000 shares of preferred stock, par
value $0.001 per share (the "Preferred Stock"). The Class A Common Stock
and the Class B Common Stock are hereinafter referred to collectively as
the "Common Stock."

                  (b) Common Stock. The powers, preferences and rights, and
the qualifications, limitations and restrictions, of each class of the
Common Stock are as follows:

                      (1) Voting Rights. Subject to the rights of the
holders of Preferred Stock, and subject to any other provisions of this
Amended and Restated Certificate of Incorporation, as it may be amended
from time to time, the shares of Common Stock shall have the following
voting rights: (i) each share of Class A Common Stock shall entitle the
holder thereof to one (1) vote upon all matters upon which stockholders
shall have the right to vote; and (ii) each share of Class B Common Stock
shall entitle the holder thereof to ten (10) votes upon all matters which
stockholders shall have the right to vote. The holders of Common Stock are
not entitled to cumulative voting rights.

                      (2) Dividends; Stock Splits. Subject to the rights of
the holders of Preferred Stock, and subject to any other provisions of this
Amended and Restated Certificate of Incorporation, as it may be amended
from time to time, holders of shares of Common Stock shall be entitled to
receive such dividends and other distributions in cash, stock or property
of the Corporation when, as and if declared thereon by the Board of
Directors from time to time out of assets or funds of the Corporation
legally available therefor. Holders of Class A Common Stock and Class B
Common Stock will share equally on a per share basis in any dividend
declared by the Board of Directors, subject to any preferential rights of
any outstanding Preferred Stock. No dividend or other distribution may be
declared or paid on any share of Class A Common Stock unless a like
dividend or other distribution is simultaneously declared or paid, as the
case may be, on each share of Class B Common Stock, nor shall any dividend
or other distribution be declared or paid on any share of Class B Common
Stock unless a like dividend or other distribution is simultaneously
declared or paid, as the case may be, on each share of Class A Common
Stock, in each case without preference or priority of any kind; provided,
however, that all dividends and distributions on the Class A Common Stock
and Class B Common Stock payable in shares of Common Stock of the
Corporation shall be made in shares of Class A Common Stock and Class B
Common Stock, respectively. In no event will shares of either class of
Common Stock be split, divided or combined unless the outstanding shares of
the other class of Common Stock shall be proportionately split, divided or
combined.

                      (3) Liquidation, Dissolution, etc. In the event of
any liquidation, dissolution or winding up (either voluntary or
involuntary) of the Corporation, the holders of shares of Class A and Class
B Common Stock shall be entitled to receive the remaining assets and funds
of the Corporation available for distribution after payments to creditors
and to the holders of any Preferred Stock of the Corporation that may at
the time be outstanding, ratably in proportion to the number of shares of
Common Stock held by them, respectively. In any such distribution, shares
of Class A Common Stock and Class B Common Stock shall be treated equally
on a per share basis.

                      (4) Merger, etc. In the event of a merger or
consolidation of the Corporation with or into another entity (whether or
not the Corporation is the surviving entity), the holders of each share of
Class A Common Stock and Class B Common Stock shall be entitled to receive
the same per share consideration as the per share consideration, if any,
received by the holders of each share of the other class of Common Stock,
except that if the consideration includes voting securities (or the right
to acquire voting securities, or securities exchangeable for, or
convertible into, voting securities), holders of Class B Common Stock shall
receive consideration entitling them to ten times the number of votes per
share as the consideration being received by holders of the Class A Common
Stock.

                      (5) Conversion of Class B Common Stock.

                           (i) Voluntary Conversion. Each share of Class B
Common Stock shall be convertible, at the option of its record holder, into
one validly issued, fully paid and non-assessable share of Class A Common
Stock at any time.

                           (ii) Automatic Conversion. In the event of any
transfer of any share of Class B Common Stock to a person or entity that
(i) is not a permitted transferee or (ii) is a permitted transferee but
ceases to be a permitted transferee subsequent to such transfer, such share
of Class B Common Stock shall automatically, without any further action,
convert into one validly issued, fully paid and non-assessable share of
Class A Common Stock. Permitted transferees shall include (A) RSL
Communications, Ltd. ("RSL COM"), (B) a majority- owned subsidiary of RSL
COM, (C) a successor of RSL COM following a merger, consolidation or
reorganization of RSL COM whereby RSL COM is not the surviving entity or
(D) Ronald S. Lauder or members of his family or a trust established by
Ronald S. Lauder for his family members, or entities controlled by or under
common control with Ronald S. Lauder. Majority-owned subsidiary for these
purposes shall mean an entity, more than 50% of the voting shares of which
are owned either directly or indirectly through one or more intermediaries,
by RSL COM.

                      (6) No Preemptive or Subscription Rights. No holder
of shares of Common Stock shall be entitled to preemptive or subscription
rights.

                      (7) Power to Sell and Purchase Shares. Subject to the
requirements of applicable law, the Corporation shall have the power to
issue and sell all or any part of any shares of any class of stock herein
or hereafter authorized to such persons, and for such consideration, as the
Board of Directors shall from time to time, in its discretion, determine,
whether or not greater consideration could be received upon the issue or
sale of the same number of shares of another class, and as otherwise
permitted by law. Subject to the requirements of applicable law, the
Corporation shall have the power to purchase any shares of any class of
stock herein or hereafter authorized from such persons, and for such
consideration, as the Board of Directors shall from time to time, in its
discretion, determine, whether or not less consideration could be paid upon
the purchase of the same number of shares of another class, and as
otherwise permitted by law.

                  (c) Preferred Stock. The Board of Directors is hereby
expressly authorized to provide for the issuance of all or any shares of
the Preferred Stock in one or more classes or series, and to fix for each
such class or series such voting powers, full or limited, or no voting
powers, and such designations, preferences and relative, participating,
optional or other special rights and such qualifications, limitations or
restrictions thereof, as shall be stated and expressed in the resolution or
resolutions adopted by the Board of Directors providing for the issuance of
such class or series and as may be permitted by the GCL, including, without
limitation, the authority to provide that any such class or series may be
(i) subject to redemption at such time or times and at such price or
prices; (ii) entitled to receive dividends (which may be cumulative or
non-cumulative) at such rates, on such conditions, and at such times, and
payable in preference to, or in such relation to, the dividends payable on
any other class or classes or any other series; (iii) entitled to such
rights upon the dissolution of, or upon any distribution of the assets of,
the Corporation; or (iv) convertible into, or exchangeable for, shares of
any other class or classes of stock, or of any other series of the same or
any other class or classes of stock, of the Corporation at such price or
prices or at such rates of exchange and with such adjustments; all as may
be stated in such resolution or resolutions.

         FIFTH: The following provisions are inserted for the management of
the business and the conduct of the affairs of the Corporation, and for
further definition, limitation and regulation of the powers of the
Corporation and of its directors and stockholders:

                  (a) The business and affairs of the Corporation shall be
managed by or under the direction of the Board of Directors.

                  (b) The number of directors of the Corporation shall be
as from time to time fixed by the Board of Directors, and such number shall
never be less than three nor more than thirteen. Election of directors need
not be by written ballot unless the By-Laws so provide.

                  (c) A director shall hold office until the annual meeting
for the year in which his or her term expires and until his or her
successor shall be elected and shall qualify, subject, however, to prior
death, resignation, retirement, disqualification or removal from office.

                  (d) Any director may be elected by a majority of the
Board of Directors to fill a vacancy. If the vacancy results from an
increase in the number of directors, such director shall hold office for a
term that shall coincide with the remaining term of directors then in
office. Any director elected to fill a vacancy not resulting from an
increase in the number of directors shall have the same remaining term as
that of his predecessor. Subject to the rights, if any, of the holders of
shares of Preferred Stock then outstanding, any or all of the directors of
the Corporation may be removed from office at any time, with or without
cause by the affirmative vote of the holders of at least a majority of the
voting power of the Corporation's then outstanding capital stock entitled
to vote generally in the election of directors. Notwithstanding the
foregoing, whenever the holders of any one or more classes or series of
Preferred Stock issued by the Corporation shall have the right, voting
separately by class or series, to elect directors at an annual or special
meeting of stockholders, the election, term of office, filling of vacancies
and other features of such directorships shall be governed by the terms of
this Amended and Restated Certificate of Incorporation applicable thereto.

                  (e) In addition to the powers and authority hereinbefore
or by statute expressly conferred upon them, the directors are hereby
empowered to exercise all such powers and do all such acts and things as
may be exercised or done by the Corporation, subject, nevertheless, to the
provisions of the GCL, this Amended and Restated Certificate of
Incorporation, and any By-Laws adopted by the stockholders; provided,
however, that no By-Laws hereafter adopted by the stockholders shall
invalidate any prior act of the directors which would have been valid if
such By-Laws had not been adopted.

         SIXTH: No director shall be personally liable to the Corporation
or any of its stockholders for monetary damages for breach of fiduciary
duty as a director, except to the extent such exemption from liability or
limitation thereof is not permitted under the GCL as the same exists or may
hereafter be amended. If the GCL is amended hereafter to authorize the
further elimination or limitation of the liability of directors, then the
liability of a director of the Corporation shall be eliminated or limited
to the fullest extent authorized by the GCL, as so amended. Any repeal or
modification of this Article SIXTH by the stockholders of the Corporation
shall not adversely affect any right or protection of a director of the
Corporation existing at the time of such repeal or modification with
respect to acts or omissions occurring prior to such repeal or
modification.

         SEVENTH: The Corporation shall indemnify its directors and
officers to the fullest extent authorized or permitted by law, as now or
hereafter in effect, and such right to indemnification shall continue as to
a person who has ceased to be a director or officer of the Corporation and
shall inure to the benefit of his or her heirs, executors and personal and
legal representatives; provided, however, that, except for proceedings to
enforce rights to indemnification, the Corporation shall not be obligated
to indemnify any director or officer (or his or her heirs, executors or
personal or legal representatives) in connection with a proceeding (or part
thereof) initiated by such person unless such proceeding (or part thereof)
was authorized or consented to by the Board of Directors. The right to
indemnification conferred by this Article SEVENTH shall include the right
to be paid by the Corporation the expenses incurred in defending or
otherwise participating in any proceeding in advance of its final
disposition.

                  The Corporation may, to the extent authorized from time
to time by the Board of Directors, provide rights to indemnification and to
the advancement of expenses to employees and agents of the Corporation
similar to those conferred in this Article SEVENTH to directors and
officers of the Corporation.

                  The rights to indemnification and to the advance of
expenses conferred in this Article SEVENTH shall not be exclusive of any
other right which any person may have or hereafter acquire under this
Amended and Restated Certificate of Incorporation, the By-Laws of the
Corporation, any statute, agreement, vote of stockholders or disinterested
directors or otherwise.

                  Any repeal or modification of this Article SEVENTH by the
stockholders of the Corporation shall not adversely affect any rights to
indemnification and to the advancement of expenses of a director or officer
of the Corporation existing at the time of such repeal or modification with
respect to any acts or omissions occurring prior to such repeal or
modification.

         EIGHTH: The Corporation hereby elects not to be governed by
Section 203 of the GCL pursuant to Section 203(b)(3) therein.

         NINTH: Meetings of stockholders may be held within or without the
State of Delaware, as the By-Laws may provide. The books of the Corporation
may be kept (subject to any provision contained in the GCL) outside the
State of Delaware at such place or places as may be designated from time to
time by the Board of Directors or in the By-Laws of the Corporation.

         TENTH: In furtherance and not in limitation of the powers
conferred upon it by the laws of the State of Delaware, the Board of
Directors or the stockholders shall have the power to adopt, amend, alter
or repeal the Corporation's By-Laws. The affirmative vote of at least a
majority of the entire Board of Directors or a majority of the voting power
of the Corporation's then outstanding capital stock entitled to vote shall
be required to adopt, amend, alter or repeal the Corporation's By-Laws.

         ELEVENTH: The Corporation reserves the right to amend, alter,
change or repeal any provision contained in this Amended and Restated
Certificate of Incorporation in the manner now or hereafter prescribed in
this Amended and Restated Certificate of Incorporation, the Corporation's
By-Laws or the GCL, and all rights herein conferred upon stockholders are
granted subject to such reservation.


         IN WITNESS WHEREOF, the Corporation has caused this Amended and
Restated Certificate of Incorporation to be executed on its behalf this day
of , 2002.

                                                     deltathree, Inc.


                                                     By:________________________
                                                     Name:
                                                     Title: