SERIES A DEBENTURE

THE SECURITIES OFFERED HEREBY HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED,  AND THE RULES AND  REGULATIONS  PROMULGATED
THEREUNDER  (THE  "1933  ACT"),  AND MAY ONLY BE  OFFERED  OR SOLD  PURSUANT  TO
REGISTRATION  UNDER OR AN EXEMPTION FROM THE  REGISTRATION  REQUIREMENTS  OF THE
1933 ACT.


                  7% CONVERTIBLE DEBENTURE DUE OCTOBER 15, 1998


$________________                                               October 15, 1996


         FOR VALUE RECEIVED,  INTELECT COMMUNICATIONS SYSTEMS LIMITED, a Bermuda
company (the "Company"),  hereby promises to pay to  _____________________  , or
registered assigns (the "Holder") on October 15, 1998 (the "Maturity Date"), the
principal  amount  of  ________________________   (______________)  and  to  pay
interest in cash on the principal amount hereof, in such amounts,  at such times
and on such terms and conditions as are specified  herein.  This Debenture (this
"Debenture") is one of two Series A Debentures issued in an aggregate  principal
amount of $5,000,000 pursuant to that certain Convertible  Securities  Agreement
executed by the Holder, the Company and _____________________  dated October 15,
1996 (the "Agreement").

ARTICLE 1.        INTEREST.

         The Company shall pay interest on the unpaid  principal  amount of this
Debenture at the rate of Seven Percent (7%) per year,  payable in cash,  payable
quarterly in arrears on each  December 31, March 31, June 30 and  September  30,
commencing  December 31, 1996 until the principal  hereof is paid in full or has
been  converted.  Interest on this  Debenture  shall accrue from the most recent
date to which interest has been paid or, if no interest has been paid,  from the
date  hereof.  Interest  shall be computed on the basis of the actual  number of
days elapsed during any interest  calculation period in a 360-day year of twelve
30-day months.

ARTICLE 2.        METHOD OF PAYMENT.

         The Company shall pay the  principal of and interest on this  Debenture
in  United   States   dollars.   Interest   shall  be  paid  to  the  holder  at
________________________.  Principal  shall be paid in the manner  described  in
that certain Book Entry Transfer

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Agent Agreement (the "Transfer Agent Agreement") among the Company,  the Holder,
______________________   and  American  Stock  Transfer  &  Trust  Company,  the
Company's  stock transfer agent (the "Transfer  Agent").  Interest and principal
payments shall be subject to withholding (if any) under applicable United States
Federal Internal Revenue Service Regulations.

ARTICLE 3.        CONVERSION.

         SECTION 3.1.  CONVERSION PRIVILEGE

         (a) The Holder of this Debenture  shall have the right,  exercisable at
one or more times, at its option,  to convert all or a portion of this Debenture
into common  shares,  par value $.01 per share (U.S.),  of the Company  ("Common
Shares"  or  "Common  Stock") at the times  hereafter  specified.  The number of
Common Shares  issuable upon the  conversion of this  Debenture is determined by
dividing the principal amount hereof to be converted by the Conversion Price (as
defined in paragraph (b) of this Section 3.1 below) in effect on the  conversion
date and rounding the result to the nearest 1/100th of a share. Upon conversion,
all accrued and unpaid interest will be paid to the Holder in cash.

         (b) All or any portion of this  Debenture is  convertible  at any time,
and from time to time as follows:  One-third  (1/3) of the principal  balance of
all Debentures  issued to Holders as described in Section 7.1 hereafter shall be
convertible  beginning  sixty  (60) days  after the date of this  Debenture;  an
additional  one-third  (1/3) of the  principal  balance  of all such  Debentures
issued to the Holders shall be  convertible  beginning 90 days after the date of
such Debentures;  and the final one-third (1/3) of the principal  balance of all
such  Debentures  issued to the Holders shall be convertible  beginning 120 days
after  the  date of such  Debentures;  provided,  that  if the  Company  has not
effected  the  registration  of the Common  Shares into which this  Debenture is
convertible on or before the expiration of the sixty (60) day period  referenced
above,  one-half (1/2) of the principal  balance of all the Debentures  shall be
convertible  at  such  time  and  the  remaining   principal  balance  shall  be
convertible  ninety (90) days after the date hereof.  The conversion price shall
be the  lesser of (A) Twelve and  No/100  Dollars  ($12.00)  per share of Common
Stock or (B) the product of (i) the current  market price of the Common Stock on
the conversion date  multiplied by (ii) eighty two and one-half  percent (82.5%)
(the "Formula Price");  provided,  if the conversion date is a date on or before
the 90th day following the date of this Debenture, the Conversion Price shall be
the greater of the Formula Price of the Common Stock on the  conversion  date or
Four and 50/00 Dollars ($4.50) per share of Common Stock (such  applicable price
being hereafter referred to as the "Conversion Price").

         (c) In the  event  any  Debenture  remains  outstanding  on the  second
anniversary of the date hereof,  the unconverted  portion of such Debenture will
automatically be

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converted  into  Common  Shares  on such  date in the  manner  set forth in this
Section  3.1;  provided  (i) an Event of Default  does not then exist under this
Debenture and (ii) a registration  statement as contemplated by Section 4 of the
Agreement  is  effective  with  respect to the sale by the  Holders of shares of
Common Stock issuable upon conversion of this Debenture.

         (d) At any time, and from time to time, the Company, at its option (the
"Redemption Option"),  may redeem this Debenture at the Agreed Redemption Amount
(which shall mean the product of the remaining principal amount of the Debenture
multiplied by 117.5%,  plus accrued and unpaid interest thereon).  Any notice of
exercise of the Redemption Option (a "Redemption  Notice") shall be delivered in
writing to Holder and shall be  irrevocable  when  delivered.  The Company shall
not,  however,  be entitled  to issue a  Redemption  Notice with  respect to any
portion of the Debenture for which Holder has  previously  delivered a Notice of
Conversion as contemplated by this Debenture,  and any such Notice of Conversion
delivered  after the Company  issues a Redemption  Notice shall be invalid.  The
Company shall pay the Agreed Redemption Amount in the manner contemplated in the
Transfer Agent  Agreement  upon exercise of the Redemption  Option within thirty
(30) days of the  delivery  of such  Redemption  Notice.  During the  Redemption
Period,  the Company  shall comply with all terms,  conditions  and covenants of
this  Debenture  (including,  without  limitation  timely payment of accrued and
unpaid  interest).  Subject to the  foregoing,  Holder's  option to convert this
Debenture  into  shares of Common  Stock shall be abated  during the  Redemption
Period.

         SECTION  3.2.  CONVERSION  PROCEDURE.  To convert this  Debenture  into
Common  Shares,  the Holder  must  complete  and sign the  Notice of  Conversion
attached hereto and deliver the same  (including  delivery via facsimile) to the
Transfer  Agent.  The date upon which the Transfer  Agent receives the completed
Notice of Conversion (by recognized overnight courier, hand-delivery,  facsimile
or otherwise) is the conversion date. Within two (2) business days after receipt
of the Notice of Conversion  as aforesaid,  the Company shall cause the Transfer
Agent to deliver a  certificate  for the number of full Common  Shares  issuable
upon the conversion and a check for any fraction of a share. The person in whose
name the  certificate  representing  Common Shares is to be registered  shall be
treated  as a  shareholder  of record on and after  the  conversion  date.  Upon
conversion,  unpaid interest on the converted  portion of the Debenture shall be
paid in cash by the Company.  If one person  converts more than one Debenture at
the same time, the number of full shares  issuable upon the conversion  shall be
based on the total principal amount of Debentures converted. Notwithstanding the
foregoing, the conversion right of the Holder set forth herein shall be limited,
solely to the extent required, from time to time, such that in no instance shall
the  maximum  number of Common  Shares  into which the Holder may  convert  this
Debenture exceed, at any one time, an amount equal to the remainder of (i) 4.99%
of the then issued and outstanding

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shares of Common Stock of the Company following such conversion,  minus (ii) the
number of shares of Common Stock of the Company then held by the Holder.

         SECTION  3.3.   FRACTIONAL  SHARES.  The  Company  shall  not  issue  a
fractional share of Common Stock upon the conversion of this Debenture. Instead,
the Company shall pay in lieu of any fractional  share the cash value thereof at
the then current  market price of the Common Shares as determined  under Section
3.7 below.

         SECTION  3.4.   TAXES  ON   CONVERSION.   The  Company  shall  pay  any
documentary,  stamp or similar  issue or transfer tax due on the issue of Common
Shares upon the conversion of this Debenture.  However, the Holder shall pay any
such tax which is due  because  such  shares are issued in a name other than its
name.

         SECTION 3.5. COMPANY TO RESERVE STOCK. The Company shall reserve out of
its  authorized  but unissued  Common  Shares enough Common Shares to permit the
conversion in full of this Debenture. All Common Shares which may be issued upon
the conversion hereof shall be fully paid and nonassessable.

         SECTION 3.6.  RESTRICTIONS  ON TRANSFER.  This Debenture and the Common
Shares issuable upon the conversion  hereof have not been  registered  under the
Securities  Act of 1933 (the "Act") and have been sold  pursuant to an exemption
under the Act. The Debenture may not be transferred or resold except pursuant to
registration under or an exemption from the Act.

         SECTION 3.7.  CURRENT MARKET PRICE.

         (a) As used herein, the current market price per share of Common Shares
on any date is the  average of the  closing  bid price of the  Common  Shares on
NASDAQ (or on such  exchange as the Common  Shares are then listed) for five (5)
consecutive trading days ending on the trading day before the date in question.

         (b) As used in this  Section 3.7, the term closing bid price shall mean
(i) the  closing  bid price  thereof on any such  trading  date,  as reported by
Bloomberg,  L.P. or (ii) in the event the Common Shares are not reported on such
system,  the fair market value of the Common Stock as determined by the Board of
Directors of the Company in its good faith judgment.

ARTICLE 4.        MERGERS.

         The Company  shall not  consolidate  or merge into,  or transfer all or
substantially  all of its assets to, any person,  unless such person assumes the
obligations  of the Company  under this  Debenture  and  immediately  after such
transaction  no Event of Default  exists.  Any  reference  herein to the Company
shall refer to such surviving or

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transferee  corporation  and the obligations of the Company shall terminate upon
such assumption.  If the Company merges or consolidates with another corporation
or sells or transfers all or  substantially  all of its assets to another person
and the holders of the Common Shares are entitled to receive  stock,  securities
or property in respect of or in exchange for Common Shares,  then as a condition
of such merger, consolidation,  sale or transfer, either (i) the Company and any
such  successor,  purchaser or transferee  shall amend this Debenture to provide
that it may  thereafter be converted on the terms and subject to the  conditions
set  forth  above  into the kind and  amount of stock,  securities  or  property
receivable upon such merger, consolidation,  sale or transfer by a holder of the
number of shares of Common  Stock  into  which  this  Debenture  might have been
converted  immediately before such merger,  consolidation,  sale or transfer, or
(ii) if the Company is not the surviving  entity in such merger,  consolidation,
sale or  transfer,  the  Company  shall  give the  Holder at least 30 days prior
written  notice of the  expected  closing date of such  transaction,  and if any
portion  of this  Debenture  has not been  converted  into  Common  Stock at the
election  of the Holder  prior to such  closing,  then the  remaining  principal
amount of this Debenture may, at the option of the Purchaser,  be converted into
shares of Common Stock at the closing of such transaction.  The Conversion Price
shall be the same as the applicable Conversion Price defined in Section 3 above.

ARTICLE 5.        REPORTS.

         The Company  will mail to the Holder  hereof at its address as shown on
the  Register a copy of any annual,  quarterly  or current  report that it files
with the  Securities and Exchange  Commission  promptly after the filing thereof
and a copy of any annual,  quarterly or other report or proxy  statement that it
gives to its shareholders generally at the time such report or statement is sent
to shareholders.

ARTICLE 6.        DEFAULTS AND REMEDIES.

         SECTION 6.1. EVENTS OF DEFAULT. An "Event of Default" occurs if (a) the
Company does not make the payment of the  principal of this  Debenture  when the
same becomes due and payable at maturity, upon redemption or otherwise,  (b) the
Company does not make a payment of interest when such  interest  becomes due and
payable and such default  continues for a period of 10 days thereafter,  (c) the
Company  fails to issue Common  Shares upon  conversion,  within the time period
specified in Section 3.2, (d) the Company  fails to comply with any of its other
agreements in this  Debenture the Company  ceases to be eligible with respect to
the use of Form S-3 for the filing of a resale  registration  statement with the
Securities and Exchange Commission,  (f) the Company's Common Shares cease to be
quoted on any of the New York  Stock  Exchange,  American  Stock  Exchange,  the
NASDAQ-National Market or NASDAQ-Small Cap for a period in excess of 60 calendar
days, (g) an "Event of Default" occurs in any of the other Debentures  issued in
connection with the Agreement, (h) the Company defaults

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(INTELECT COMMUNICATIONS SYSTEMS LIMITED)





under the terms of any existing or "funded  indebtedness" in excess of $500,000,
and such default is not remedied within the cure period associated therewith, or
(i) the  Company  pursuant to or within the  meaning of any  Bankruptcy  Law (as
hereinafter defined):  (a) commences a voluntary case; (b) consents to the entry
of an order for relief  against it in an  involuntary  case; (c) consents to the
appointment  of a  Custodian  (as  hereinafter  defined)  of it or  for  all  or
substantially  all of its  property;  (d)  makes a  general  assignment  for the
benefit of its  creditors;  or (e) a court of competent  jurisdiction  enters an
order or decree under any  Bankruptcy  Law that:  (A) is for relief  against the
Company in an  involuntary  case; (B) appoints a Custodian of the Company or for
all or  substantially  all of its property or (C) orders the  liquidation of the
Company,  and the order or decree remains unstayed and in effect for 60 days. As
used in this Section 6.1, the term "Bankruptcy Law" means Title 11 of the United
States  Code or any  similar  Federal  or State law for the relief of debtors or
such other applicable laws. The term  "Custodian"  means any receiver,  trustee,
assignee,  liquidator or similar  official  under any  Bankruptcy  Law. The term
"funded   indebtedness"   means  indebtedness  for  borrowed  money  of  Seller,
indebtedness evidenced by securities,  debentures, bonds, notes or other similar
instruments issued by Seller, all obligations of Seller issued or assumed as the
deferred purchase price of property,  all liabilities secured by any lien on any
property or asset of Seller and all  obligations  of the type referred to herein
of other  persons for the payment of which  Seller is  responsible  or liable as
obligor, guarantor, or otherwise.

         SECTION  6.2.  ACCELERATION.  If an  Event  of  Default  occurs  and is
continuing,  the  Holder  hereof by  notice  to the  Company,  may  declare  the
principal of and accrued interest on this Debenture to be due and payable.  Upon
such  declaration,  the principal  and interest  hereof shall be due and payable
immediately.

ARTICLE 7.        REGISTERED DEBENTURES.

         SECTION 7.1.  SERIES.  This Debenture is one of two Series A Debentures
issued to the Holder and  Seacrest  Capital  Limited  pursuant to the  Agreement
having  an  aggregate  principal  amount  of Five  Million  and  No/100  Dollars
($5,000,000),  which are  identical.  Such  Debentures  are  referred  to herein
collectively as the "Debentures."

         SECTION 7.2. RECORD OWNERSHIP. The Company,  pursuant to the mechanisms
established under the Transfer Agent Agreement, shall maintain a register of the
holders of the Debentures (the "Register") showing their names and addresses and
the serial numbers and principal  amounts of Debentures issues to or transferred
of  record  by them  from  time to  time.  The  Register  may be  maintained  in
electronic,  magnetic  or other  computerized  form.  The  Company may treat the
person  named as the Holder of this  Debenture in the Register as the sole owner
of this  Debenture.  The  registered  Holder  of this  Debenture  is the  person
exclusively entitled to receive payments of interest on this Debenture,  receive
notifications with respect to this Debenture, convert it into

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Common Stock and otherwise exercise all of the rights and powers as the absolute
owner hereof.

         SECTION 7.3. REGISTRATION OF TRANSFER.  Transfers of this Debenture may
be registered on the books of the Company  maintained for such purpose  pursuant
to Section 7.2 above (i.e.,  the Register).  Transfers  shall be registered when
the Transfer Agent is presented  with a request to register the transfer  hereof
pursuant  to the terms of the  Transfer  Agent  Agreement  and the  Company  has
received  evidence  satisfactory  to it that such  transfer is  rightful  and in
compliance  with all applicable  laws,  including tax laws and State and Federal
securities laws.

ARTICLE 8.        NOTICES.

         Any notice  which is required  by the  Company  under the terms of this
Debentures  shall be duly given if it is in writing and delivered in person,  by
telecopy, by recognized overnight courier or mailed by first class mail, postage
prepaid and directed to the Holder of the Debenture at its address as it appears
on the Register or if to the Company to its  principal  executive  offices.  The
time when such notice is sent shall be the time of the giving of the notice.

         All notices to Holders are to be mailed to:

         --------------------------
         --------------------------
         --------------------------
         --------------------------
         Telephone:  _______________
         Fax:  _____________________

         All notices to the Company are to be mailed to:

         Intelect Communications Systems Limited
         Reid House 31 Church Street
         Hamilton, Bermuda
         Attn:  President
         Telephone:  441/295-8639
         Fax:  441/292-5560


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         With copy to:

         Hale and Dorr
         60 State Street
         Boston, Massachusetts 02109
         Telephone:  617/526-6000
         Fax:  617/526-5000
         Attn:  Philip P. Rossetti


ARTICLE 9.        TIMES.

         Where this Debenture authorizes or requires the payment of money or the
performance  of a condition  or  obligation  on a Saturday or Sunday or a public
holiday,  or authorizes or requires the payment of money or the performance of a
condition or obligation within, before or after a period of time computed from a
certain date, and such period of time ends on a Saturday or a Sunday or a public
holiday,  such payment may be made or condition or  obligation  performed on the
next  succeeding  business day, and if the period ends at a specified hour, such
payment may be made or condition  performed,  at or before the same hour of such
next  succeeding  business  day,  with the same  force and  effect as if made or
performed in accordance with the terms of this Debenture. Where time is extended
by virtue of the  provisions  of this Article 9, such extended time shall not be
included in the computation of interest.

ARTICLE 10.       RULES OF CONSTRUCTION.

         In this Debenture,  unless the context otherwise requires, words in the
singular number include the plural, and in the plural include the singular,  and
words of the masculine gender include the feminine and the neuter,  and when the
sense so  indicates,  words of the neuter  gender may refer to any  gender.  The
numbers and titles of sections  contained  in this  Debenture  are  inserted for
convenience  of reference  only,  and they neither form a part of this Debenture
nor are they to be used in the construction or interpretation hereof.  Wherever,
in this Debenture,  a determination of the Company is required or allowed,  such
determination  shall be made by a  majority  of the  Board of  Directors  of the
Company and if it is made in good faith, it shall be conclusive and binding upon
the Company and the Holder of this Debenture.

ARTICLE 11.       GOVERNING LAW.

         The validity,  terms,  performance  and  enforcement  of this Debenture
shall be governed and construed by the provisions  hereof and in accordance with
the laws of Bermuda.
                            [Signature page follows]

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         IN WITNESS WHEREOF,  the Company has duly executed this Debenture as of
the date first written above.

                                     INTELECT COMMUNICATIONS SYSTEMS
                                     LIMITED



                                     By:
                                        ------------------------------
                                     Name     PETER G. LEIGHTON
                                         -----------------------------
                                     Title             PRESIDENT
                                          ----------------------------

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                              NOTICE OF CONVERSION

         [To be completed and signed only upon conversion of Debenture]

         The  undersigned,  the  Holder of this  Debenture,  hereby  irrevocably
elects to exercise the right to convert it into common shares, par value $10 per
share, of Intelect Communications Systems Limited as follows:

[Complete if less than all                      Dollars ($       )
of principal amount is to          ---------------------------------------------
be converted                       ($10,000 or integral multiples of $10,000)

[Signature must be                 ---------------------------------------------
guaranteed if registered           (Name of Holder of shares if different than
holder of stock differs            registered Holder of Debenture)
from registered Holder of
Debenture)
                                   ---------------------------------------------
                                   (Address of Holder if different than address
                                   of registered Holder of Debenture)


                                   ---------------------------------------------
                                   (Social Security of EIN of Holder of shares
                                   if different than Holder of Debenture)


Date:_________              Sign:  _____________________________________________
                                   (Signature must conform in all respects to
                                    name of Holder shown on face of this
                                    Debenture)

NOTICE OF CONVERSION