EXHIBIT 10.8

                                            SUBSIDIARY GUARANTEE AGREEMENT dated
                           as of March 13,  1996, among each of the subsidiaries
                           listed on  Schedule I  hereto  (each such  subsidiary
                           individually,  a "Guarantor"  and  collectively,  the
                           "Guarantors")   of  SHARED   TECHNOLOGIES   FAIRCHILD
                           COMMUNICATIONS  CORP.,  a Delaware  corporation  (the
                           "Borrower"), or SHARED TECHNOLOGIES FAIRCHILD INC., a
                           Delaware corporation  ("STFI"),  and CREDIT SUISSE, a
                           bank organized under the laws of Switzerland,  acting
                           through its New York branch, as collateral agent (the
                           "Collateral  Agent")  for  the  Secured  Parties  (as
                           defined in the Credit Agreement referred to below).

                  Reference  is made to the Credit  Agreement  dated as of March
12, 1996 (as amended,  supplemented or otherwise modified from time to time, the
"Credit  Agreement"),  among the Borrower,  STFI,  the lenders from time to time
party thereto (the "Lenders"),  Credit Suisse, as administrative  agent (in such
capacity, the "Administrative Agent") and as collateral agent (in such capacity,
the  "Collateral  Agent")  for  the  Lenders,   the  fronting  banks  listed  on
Schedule 2.20  (the  "Fronting  Banks"),  and each of  Citicorp  USA,  Inc.  and
NationsBank, N.A., as documentation agent (individually and collectively in such
capacity,  the  "Documentation  Agent").  Capitalized  terms used herein and not
defined  herein  shall have the  meanings  assigned  to such terms in the Credit
Agreement.

                  The Lenders have agreed to make Loans to the Borrower, and the
Fronting  Banks have  agreed to issue  Letters of Credit for the  account of the
Borrower,  pursuant  to,  and upon  the  terms  and  subject  to the  conditions
specified  in, the Credit  Agreement.  Each of the  Guarantors is a wholly owned
Subsidiary  of the Borrower  and  acknowledges  that it will derive  substantial
benefit  from the making of the Loans by the  Lenders,  and the  issuance of the
Letters of Credit by the Fronting Banks.  The obligations of the Lenders to make
Loans and of the Fronting Banks to issue Letters of Credit are  conditioned  on,
among other things,  the execution and delivery by the Guarantors of a Guarantee
Agreement in the form hereof.  As consideration  therefor and in order to induce
the Lenders to make Loans and the Fronting Banks to issue Letters of Credit, the
Guarantors are willing to execute this Agreement.

                  Accordingly, the parties hereto agree as follows:

                  SECTION 1. Guarantee.    Each    Guarantor    unconditionally
guarantees,  jointly  with the  other  Guarantors  and  severally,  as a primary
obligor and not merely as a surety,  (a) the due and punctual payment of (i) the
principal of and premium,  if any, and  interest  (including  interest  accruing
during the pendency of any bankruptcy, insolvency, receivership or other similar
proceeding,  regardless of whether  allowed or allowable in such  proceeding) on
the Loans,  when and as due, whether at maturity,  by acceleration,  upon one or
more dates set for  prepayment  or otherwise,  (ii) each payment  required to be
made by the  Borrower  under the  Credit  Agreement  in respect of any Letter of
Credit,  when and as due,  including  payments  in respect of  reimbursement  of
disbursements,  interest  thereon and obligations to provide cash collateral and
(iii) all  other  monetary  obligations,  including  fees,  costs,  expenses and
indemnities,  whether primary, secondary, direct, contingent, fixed or otherwise
(including monetary  obligations incurred during the pendency of any bankruptcy,
insolvency,  receivership  or other  similar  proceeding,  regardless of whether
allowed or  allowable  in such  proceeding),  of the Loan Parties to the Secured
Parties under the Credit Agreement and the other Loan Documents, (b) the due and
punctual performance of all covenants,  agreements,  obligations and liabilities
of the Loan Parties under or pursuant to the Credit Agreement and the other Loan
Documents  and (c) unless  otherwise  agreed  



upon in writing by the applicable  Lender party thereto,  all obligations of the
Borrower,  monetary or otherwise,  under each Interest Rate Protection Agreement
entered  into with a  counterparty  that was a Lender at the time such  Interest
Rate  Protection  Agreement  was  entered  into  (all  the  monetary  and  other
obligations  referred  to  in  the  preceding   clauses (a)  through  (c)  being
collectively called the  "Obligations").  Each Guarantor further agrees that the
Obligations may be extended or renewed,  in whole or in part,  without notice to
or further  assent  from it, and that it will  remain  bound upon its  guarantee
notwithstanding  any  extension  or renewal of any  Obligation.  Each  Guarantor
further agrees that (a) the maturity of the Obligations guaranteed hereby may be
accelerated as provided in Article VII of the Credit  Agreement for the purposes
of such Guarantor's  guarantee herein,  notwithstanding any stay,  injunction or
other  prohibition  preventing  such  acceleration in respect of the Obligations
guaranteed  hereby,  and (y) in the event of any  declaration of acceleration of
such obligations as provided in such Article VII,  such Obligations  (whether or
not due and payable)  shall  forthwith  become due and payable by such Guarantor
for the purposes of this Section.

                  Anything   contained   in  this   Agreement  to  the  contrary
notwithstanding, the obligations of each Guarantor hereunder shall be limited to
a maximum  aggregate  amount equal to the greatest  amount that would not render
such  Guarantor's  obligations  hereunder  subject to  avoidance as a fraudulent
transfer or conveyance  under  Section 548 of Title 11 of the United States Code
or any  provisions  of  applicable  state  law  (collectively,  the  "Fraudulent
Transfer  Laws"),  in each case after giving effect to all other  liabilities of
such Guarantor,  contingent or otherwise, that are relevant under the Fraudulent
Transfer  Laws  (specifically  excluding,   however,  any  liabilities  of  such
Guarantor  (a) in  respect  of  intercompany  indebtedness  to the  Borrower  or
Affiliates  of the  Borrower  to the  extent  that  such  indebtedness  would be
discharged in an amount equal to or offset by the amount paid by such  Guarantor
hereunder  and  (b) under  any  Guarantee of senior  unsecured  indebtedness  or
Indebtedness subordinated in right of payment to the Obligations which Guarantee
contains a  limitation  as to maximum  amount  similar to that set forth in this
paragraph,  pursuant  to which the  liability  of such  Guarantor  hereunder  is
included in the  liabilities  taken into  account in  determining  such  maximum
amount) and after giving effect as assets to the value (as determined  under the
applicable  provisions  of  the  Fraudulent  Transfer  Laws)  of any  rights  to
subrogation,  contribution,  reimbursement,  indemnity or similar rights of such
Guarantor pursuant to (i) applicable law or (ii) any agreement  providing for an
equitable  allocation  among such Guarantor and other Affiliates of the Borrower
of  obligations   arising  under  Guarantees  by  such  parties  (including  the
Indemnity, Subrogation and Contribution Agreement).

                  SECTION 2.  Obligations  Not  Waived.  To the  fullest  extent
permitted by applicable  law, each Guarantor  waives  presentment  to, demand of
payment  from and protest to the  Borrower of any of the  Obligations,  and also
waives  notice  of  acceptance  of its  guarantee  and  notice  of  protest  for
nonpayment.  To the fullest extent  permitted by applicable law, the obligations
of each  Guarantor  hereunder  shall not be affected  by (a) the  failure of the
Collateral  Agent or any other Secured Party to assert any claim or demand or to
enforce  or  exercise  any right or remedy  against  the  Borrower  or any other
Guarantor under the provisions of the Credit Agreement,  any other Loan Document
or otherwise,  (b) any rescission,  waiver, amendment or modification of, or any
release from any of the terms or  provisions of this  Agreement,  any other Loan
Document,  any Guarantee or any other  agreement,  including with respect to any
other  Guarantor under this Agreement or (c) the failure to perfect any security
interest in, or the release of, any of the security  held by or on behalf of the
Collateral Agent or any other Secured Party.

                  SECTION  3.  Security.  Each of the Guarantors  authorizes the
Collateral  Agent and each of the other  Secured  Parties,  to (a) take and hold
security for the payment of this  Guarantee  and the  

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Obligations  and  exchange,  enforce,  waive  and  release  any  such  security,
(b) apply  such  security and direct the order or manner of sale thereof as they
in their sole  discretion may determine and (c) release or substitute any one or
more endorsees, other guarantors of other obligors.

                  SECTION 4.  Guarantee   of  Payment.  Each  Guarantor  further
agrees that its guarantee constitutes a guarantee of payment when due and not of
collection,  and  waives  any  right to  require  that any  resort be had by the
Collateral  Agent or any other  Secured  Party to any of the  security  held for
payment of the Obligations or to any balance of any deposit account or credit on
the books of the  Collateral  Agent or any other  Secured  Party in favor of the
Borrower or any other person.

                  SECTION 5.  No  Discharge or  Diminishment  of Guarantee.  The
obligations of each Guarantor  hereunder  shall not be subject to any reduction,
limitation,   impairment  or   termination   for  any  reason  (other  than  the
indefeasible payment in full in cash of the Obligations), including any claim of
waiver, release, surrender,  alteration or compromise of any of the Obligations,
and shall not be subject to any defense or setoff,  counterclaim,  recoupment or
termination   whatsoever   by   reason   of  the   invalidity,   illegality   or
unenforceability   of  the  Obligations  or  otherwise.   Without  limiting  the
generality of the foregoing,  the obligations of each Guarantor  hereunder shall
not be  discharged  or  impaired  or  otherwise  affected  by the failure of the
Collateral  Agent or any other Secured Party to assert any claim or demand or to
enforce any remedy under the Credit  Agreement,  any other Loan  Document or any
other agreement,  by any waiver or modification of any provision of any thereof,
by any default, failure or delay, wilful or otherwise, in the performance of the
Obligations,  or by any other act or omission that may or might in any manner or
to any extent vary the risk of any Guarantor or that would otherwise  operate as
a  discharge  of each  Guarantor  as a matter of law or equity  (other  than the
indefeasible payment in full in cash of all the Obligations).

                  SECTION 6.  Defenses of Borrower Waived. To the fullest extent
permitted by applicable law, each of the Guarantors  waives any defense based on
or arising out of any defense of the  Borrower  or the  unenforceability  of the
Obligations or any part thereof from any cause,  or the cessation from any cause
of the liability of the Borrower,  other than the final and indefeasible payment
in full in cash of the  Obligations.  The Collateral Agent and the other Secured
Parties may, at their election, foreclose on any security held by one or more of
them by one or more judicial or nonjudicial  sales,  accept an assignment of any
such  security  in lieu of  foreclosure,  compromise  or adjust  any part of the
Obligations,  make any  other  accommodation  with  the  Borrower  or any  other
guarantor  or exercise  any other right or remedy  available to them against the
Borrower or any other guarantor,  without  affecting or impairing in any way the
liability of any Guarantor  hereunder  except to the extent the Obligations have
been fully,  finally and indefeasibly paid in cash.  Pursuant to applicable law,
each of the Guarantors  waives any defense arising out of any such election even
though  such  election  operates,  pursuant to  applicable  law, to impair or to
extinguish any right of reimbursement or subrogation or other right or remedy of
such Guarantor against the Borrower or any other Guarantor or guarantor,  as the
case may be, or any security.

                  SECTION 7.  Agreement to Pay; Subordination. In furtherance of
the foregoing and not in limitation of any other right that the Collateral Agent
or any other  Secured  Party has at law or in equity  against any  Guarantor  by
virtue  hereof,  upon the failure of the Borrower or any other Loan Party to pay
any Obligation  when and as the same shall become due,  whether at maturity,  by
acceleration,  after notice of prepayment or otherwise,  each  Guarantor  hereby
promises to and will forthwith pay, or cause to be paid, to the Collateral Agent
or such other  Secured  Party as  designated  thereby in cash the amount of such
unpaid Obligations.  Upon payment by any Guarantor of any sums to the Collateral

                                       3


Agent or any  Secured  Party as  provided  above,  all rights of such  Guarantor
against the Borrower arising as a result thereof by way of right of subrogation,
contribution,  reimbursement,  indemnity or  otherwise  shall in all respects be
subordinate and junior in right of payment to the prior indefeasible  payment in
full in cash  of all the  Obligations.  In  addition,  any  indebtedness  of the
Borrower now or hereafter held by any Guarantor is hereby  subordinated in right
of payment to the prior payment in full of the Obligations.  If any amount shall
erroneously  be  paid to any  Guarantor  on  account  of  (i) such  subrogation,
contribution,  reimbursement,  indemnity  or  similar  right  or  (ii) any  such
indebtedness of the Borrower, such amount shall be held in trust for the benefit
of the Secured Parties and shall forthwith be paid to the Collateral Agent to be
credited against the payment of the  Obligations,  whether matured or unmatured,
in accordance with the terms of the Loan Documents.

                  SECTION 8.  Information.  Each of the  Guarantors  assumes all
responsibility for being and keeping itself informed of the Borrower's financial
condition and assets,  and of all other  circumstances  bearing upon the risk of
nonpayment of the Obligations and the nature, scope and extent of the risks that
such  Guarantor  assumes  and  incurs  hereunder,  and  agrees  that none of the
Collateral  Agent or the other Secured  Parties will have any duty to advise any
of the  Guarantors  of  information  known to it or any of them  regarding  such
circumstances or risks.

                  SECTION 9.  Representations   and  Warranties.   Each  of  the
Guarantors  represents  and warrants as to itself that all  representations  and
warranties  relating  to it  contained  in the  Credit  Agreement  are  true and
correct.

                  SECTION 10.  Termination.  The  Guarantees  made hereunder (a)
shall terminate when all the Obligations have been indefeasibly paid in full and
the Lenders have no further  commitment to lend under the Credit Agreement,  the
L/C Exposure  has been  reduced to zero and the  Fronting  Banks have no further
obligation to issue  Letters of Credit under the Credit  Agreement and (b) shall
continue to be  effective or be  reinstated,  as the case may be, if at any time
payment,  or any part thereof,  of any Obligation is rescinded or must otherwise
be  restored  by any  Secured  Party or any  Guarantor  upon the  bankruptcy  or
reorganization of the Borrower, any Guarantor or otherwise.

                  SECTION 11.  Binding  Effect; Several Agreement;  Assignments.
Whenever  in this  Agreement  any of the  parties  hereto is  referred  to, such
reference  shall be deemed to include the  successors and assigns of such party;
and all  covenants,  promises and  agreements by or on behalf of the  Guarantors
that are contained in this Agreement shall bind and inure to the benefit of each
party hereto and their respective  successors and assigns.  This Agreement shall
become  effective as to any  Guarantor  when a  counterpart  hereof  executed on
behalf of such Guarantor shall have been delivered to the Collateral  Agent, and
a counterpart hereof shall have been executed on behalf of the Collateral Agent,
and thereafter shall be binding upon such Guarantor and the Collateral Agent and
their respective  successors and assigns, and shall inure to the benefit of such
Guarantor,  the  Collateral  Agent  and the  other  Secured  Parties,  and their
respective successors and assigns, except that no Guarantor shall have the right
to assign its rights or  obligations  hereunder or any interest  herein (and any
such  attempted  assignment  shall be void).  If all of the  capital  stock of a
Guarantor  is  sold,   transferred  or  otherwise  disposed  of  pursuant  to  a
transaction  permitted by Section 6.05 of the Credit  Agreement,  such Guarantor
shall be released from its  obligations  under this  Agreement  without  further
action.  This Agreement shall be construed as a separate  agreement with respect
to each Guarantor and may be amended, modified, supplemented, waived or released
with respect to any  Guarantor  without the approval of any other  Guarantor and
without affecting the obligations of any other Guarantor hereunder.

                                       4


                  SECTION 12. Waivers;  Amendment.  (a)  No failure or delay of
the Collateral Agent in exercising any power or right hereunder shall operate as
a waiver thereof,  nor shall any single or partial exercise of any such right or
power, or any abandonment or  discontinuance of steps to enforce such a right or
power,  preclude  any other or further  exercise  thereof or the exercise of any
other right or power.  The rights and remedies of the Collateral Agent hereunder
and of the other Secured  Parties under the other Loan  Documents are cumulative
and are not exclusive of any rights or remedies that they would  otherwise have.
No waiver of any provision of this  Agreement or consent to any departure by any
Guarantor  therefrom  shall in any event be  effective  unless the same shall be
permitted  by  paragraph (b)  below,  and then such  waiver or consent  shall be
effective only in the specific  instance and for the purpose for which given. No
notice or demand on any  Guarantor in any case shall  entitle such  Guarantor to
any other or further notice or demand in similar or other circumstances.

                  (b)  Neither  this  Agreement nor any provision  hereof may be
waived,  amended or modified except pursuant to a written agreement entered into
between  the  Guarantors  with  respect  to  which  such  waiver,  amendment  or
modification relates and the Collateral Agent, with the prior written consent of
the Required Lenders (except as otherwise provided in the Credit Agreement).

                  SECTION 13.  Governing  Law. THIS AGREEMENT  SHALL BE GOVERNED
BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                  SECTION 14.  Notices. All communications and notices hereunder
shall be in  writing  and  given  as  provided  in  Section  9.01 of the  Credit
Agreement.  All  communications and notices hereunder to each Guarantor shall be
given to it at its address set forth in Schedule I with a copy to the Borrower.

                  SECTION 15.  Survival  of  Agreement;  Severability.  (a)  All
covenants,  agreements,  representations  and warranties  made by the Guarantors
herein and in the  certificates  or other  instruments  prepared or delivered in
connection  with or pursuant to this  Agreement or any other Loan Document shall
be  considered  to have been relied upon by the  Collateral  Agent and the other
Secured Parties and shall survive the making by the Lenders of the Loans and the
issuance  of the  Letters  of Credit by the  Fronting  Banks  regardless  of any
investigation made by the Secured Parties or on their behalf, and shall continue
in full force and effect as long as the principal of or any accrued  interest on
any Loan or any other fee or amount  payable  under this  Agreement or any other
Loan Document is outstanding  and unpaid or the L/C Exposure does not equal zero
and as long as the Commitments and the L/C Commitment have not been terminated.

                  (b)  In the event any one or more of the provisions  contained
in this Agreement or in any other Loan Document should be held invalid,  illegal
or unenforceable in any respect,  the validity,  legality and  enforceability of
the remaining  provisions  contained  herein and therein shall not in any way be
affected  or impaired  thereby (it being  understood  that the  invalidity  of a
particular  provision  in a particular  jurisdiction  shall not in and of itself
affect the validity of such  provision in any other  jurisdiction).  The parties
shall  endeavor in good-faith  negotiations  to replace the invalid,  illegal or
unenforceable  provisions  with valid  provisions  the economic  effect of which
comes as close as  possible  to that of the  invalid,  illegal or  unenforceable
provisions.

                  SECTION 16.  Counterparts.  This  Agreement may be executed in
counterparts,  each of which shall constitute an original, but all of which when
taken together shall constitute a single 

                                       5


contract,  and shall become effective as provided in Section 11.  Delivery of an
executed signature page to this Agreement by facsimile  transmission shall be as
effective as delivery of a manually executed counterpart of this Agreement.

                  SECTION 17.  Rules    of   Interpretation.    The   rules   of
interpretation  specified  in  Section 1.02  of the  Credit  Agreement  shall be
applicable to this Agreement.

                  SECTION 18.  Jurisdiction;  Consent  to  Service  of  Process.
(a) Each Guarantor hereby irrevocably and  unconditionally  submits,  for itself
and its property,  to the nonexclusive  jurisdiction of any New York State court
or Federal court of the United States of America  sitting in New York City,  and
any appellate court from any thereof, in any action or proceeding arising out of
or relating to this Agreement or the other Loan Documents, or for recognition or
enforcement of any judgment,  and each of the parties hereto hereby  irrevocably
and  unconditionally  agrees  that all claims in  respect of any such  action or
proceeding  may be heard and determined in such New York State or, to the extent
permitted by law, in such Federal court.  Each of the parties hereto agrees that
a final judgment in any such action or proceeding shall be conclusive and may be
enforced in other  jurisdictions  by suit on the judgment or in any other manner
provided  by law.  Nothing  in this  Agreement  shall  affect any right that the
Collateral  Agent or any other  Secured  Party may  otherwise  have to bring any
action or  proceeding  relating to this  Agreement  or the other Loan  Documents
against any Guarantor or its properties in the courts of any jurisdiction.

                  (b)  Each  Guarantor  hereby  irrevocably and  unconditionally
waives,  to the  fullest  extent  it may  legally  and  effectively  do so,  any
objection  that it may now or hereafter have to the laying of venue of any suit,
action or proceeding  arising out of or relating to this  Agreement or the other
Loan  Documents  in any New York State or  Federal  court.  Each of the  parties
hereto hereby  irrevocably  waives,  to the fullest extent permitted by law, the
defense of an inconvenient forum to the maintenance of such action or proceeding
in any such court.

                  (c)  Each  party to this  Agreement  irrevocably  consents  to
service of process in the manner provided for notices in Section 14.  Nothing in
this  Agreement  will affect the right of any party to this  Agreement  to serve
process in any other manner permitted by law.

                  SECTION 19.  Waiver  of Jury Trial.  EACH PARTY HERETO  HEREBY
WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE
TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION  DIRECTLY OR INDIRECTLY  ARISING
OUT OF, UNDER OR IN CONNECTION  WITH THIS AGREEMENT OR THE OTHER LOAN DOCUMENTS.
EACH PARTY HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY
OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD
NOT,  IN THE EVENT OF  LITIGATION,  SEEK TO  ENFORCE  THE  FOREGOING  WAIVER AND
(B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HERETO HAVE BEEN INDUCED TO ENTER
INTO THIS AGREEMENT AND THE OTHER LOAN DOCUMENTS, AS APPLICABLE, BY, AMONG OTHER
THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 19.

                  SECTION 20.  Additional  Guarantors.  Pursuant to Section 5.11
of the Credit Agreement, each Subsidiary of STFI, the Borrower or any Subsidiary
that was not in  existence  on the date of the Credit  Agreement  is required to
enter into this  Agreement  as a  Guarantor  upon  becoming a  

                                       6


Subsidiary.  Upon execution and delivery after the date hereof by the Collateral
Agent  and such a  Subsidiary  of an  instrument  in the form of  Annex 1,  such
Subsidiary shall become a Guarantor  hereunder with the same force and effect as
if  originally  named as a Guarantor  herein.  The execution and delivery of any
instrument adding an additional Guarantor as a party to this Agreement shall not
require the consent of any other Guarantor hereunder. The rights and obligations
of  each   Guarantor   hereunder   shall   remain  in  full   force  and  effect
notwithstanding the addition of any new Guarantor as a party to this Agreement.

                  SECTION 21.  Right  of Setoff.  If an Event of  Default  shall
have occurred and be continuing,  each Secured Party is hereby authorized at any
time and from time to time, to the fullest  extent  permitted by law, to set off
and apply any and all deposits (general or special, time or demand,  provisional
or  final) at any time held and  other  Indebtedness  at any time  owing by such
Secured Party to or for the credit or the account of any  Guarantor  against any
or all the  obligations of such  Guarantor now or hereafter  existing under this
Agreement and the other Loan Documents held by such Secured Party,  irrespective
of  whether or not such  Secured  Party  shall  have made any demand  under this
Agreement  or any other Loan  Document  and  although  such  obligations  may be
unmatured.  The  rights of each  Secured  Party  under  this  Section  21 are in
addition to other rights and remedies  (including  other rights of setoff) which
such Secured Party may have.

                                       7


                  IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement as of the day and year first above written.

                          SHARED TECHNOLOGIES FAIRCHILD
                          COMMUNICATIONS CORP.,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer


                          MULTI-TENANT SERVICES, INC.,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer


                          BOSTON TELECOMMUNICATIONS GROUP,
                          INC., d/b/a BOSTON TELECOMMUNICATIONS
                          COMPANY,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer


                          FINANCIAL PLACE COMMUNICATIONS 
                          COMPANY,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer of Shared
                                     Technologies Fairchild Inc., its General
                                     Partner
                     
                          STI INTERNATIONAL, INC.,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer

                                       8


                          OFFICE TELEPHONE MANAGEMENT,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer


                          VSI CORPORATION,

                          by
                             /s/ Vincent DiVincenzo
                             Name:  Vincent DiVincenzo
                             Title:  Authorized Officer


                          CREDIT SUISSE, as Collateral Agent,

                          by
                             /s/ Kathleen D. O'Brien
                             Name:  Kathleen D. O'Brien
                             Title:   Member of Senior Management

                          by
                             /s/ Will Ziglar
                             Name:  Will Ziglar
                             Title:   Associate

                                       9



                                                              SCHEDULE I TO THE
                                                            GUARANTEE AGREEMENT


                  Guarantor                                      Address















                                                                Annex 1 to the
                                                Subsidiary Guarantee Agreement




                                      SUPPLEMENT NO.  dated as of       , to the
                           Subsidiary  Guarantee Agreement dated as of March 12,
                           1996,  among  each  of  the  subsidiaries  listed  on
                           Schedule I     thereto    (each    such    subsidiary
                           individually,  a "Guarantor"  and  collectively,  the
                           "Guarantors")   of  SHARED   TECHNOLOGIES   FAIRCHILD
                           COMMUNICATIONS  CORP.,  a Delaware  corporation  (the
                           "Borrower"), or SHARED TECHNOLOGIES FAIRCHILD INC., a
                           Delaware corporation  ("STFI"),  and CREDIT SUISSE, a
                           bank organized under the laws of Switzerland,  acting
                           through its New York branch, as collateral agent (the
                           "Collateral  Agent")  for  the  Secured  Parties  (as
                           defined in the Credit Agreement referred to below).

                  A. Reference is made to the Credit Agreement dated as of March
12, 1996 (as amended,  supplemented or otherwise modified from time to time, the
"Credit  Agreement"),  among the Borrower,  STFI,  the lenders from time to time
party thereto (the "Lenders"),  Credit Suisse, as administrative  agent (in such
capacity, the "Administrative Agent") and as collateral agent (in such capacity,
the  "Collateral  Agent")  for  the  Lenders,   the  fronting  banks  listed  on
Schedule 2.20  (the  "Fronting  Banks"),  and each of  Citicorp  USA,  Inc.  and
NationsBank, N.A., as documentation agent (individually and collectively in such
capacity,  the  "Documentation  Agent").  Capitalized  terms used herein and not
defined  herein  shall have the  meanings  assigned  to such terms in the Credit
Agreement.

                  B.  Capitalized  terms used herein and not  otherwise  defined
herein shall have the meanings assigned to such terms in the Guarantee Agreement
and the Credit Agreement.

                  C. The Guarantors have entered into the Guarantee Agreement in
order to  induce  the  Lenders  to make  Loans and the  Fronting  Banks to issue
Letters  of Credit.  Pursuant  to Section  5.11 of the  Credit  Agreement,  each
Subsidiary of STFI, the Borrower or any Subsidiary  that was not in existence or
not a Subsidiary  on the date of the Credit  Agreement is required to enter into
the Guarantee Agreement as a Guarantor upon becoming a Subsidiary. Section 20 of
the Guarantee  Agreement  provides that additional  Subsidiaries of the Borrower
may become Guarantors under the Guarantee Agreement by execution and delivery of
an instrument in the form of this Supplement.  The undersigned Subsidiary of the
Borrower (the "New  Guarantor") is executing this  Supplement in accordance with
the  requirements  of the  Credit  Agreement  to  become a  Guarantor  under the
Guarantee  Agreement in order to induce the Lenders to make additional Loans and
the Fronting Banks to issue  additional  Letters of Credit and as  consideration
for Loans previously made and Letters of Credit previously issued.

                  Accordingly,  the Collateral Agent and the New Guarantor agree
as follows:

                  SECTION 1. In  accordance  with  Section 20  of the  Guarantee
Agreement,  the New Guarantor by its signature  below becomes a Guarantor  under
the Guarantee  Agreement  with the same force and effect as if originally  named
therein as a Guarantor and the New Guarantor hereby  (a) agrees to all the terms
and  provisions  of the  Guarantee  Agreement  applicable  to it as a  Guarantor
thereunder  and  (b) represents  and  warrants  that  the   representations  and
warranties  made by it as a Guarantor  thereunder are true and correct on and as
of the date hereof.  Each reference to a "Guarantor" in the Guarantee  Agreement
shall be deemed to include the New Guarantor.  The Guarantee Agreement is hereby
incorporated herein by reference.

                  SECTION 2. The New  Guarantor  represents  and warrants to the
Collateral  Agent



and the other Secured  Parties that this  Supplement  has been duly  authorized,
executed  and  delivered  by it and  constitutes  its legal,  valid and  binding
obligation, enforceable against it in accordance with its terms.



                  SECTION 3. This  Supplement  may be executed in  counterparts,
each of which shall constitute an original, but all of which when taken together
shall constitute a single contract.  This Supplement shall become effective when
the Collateral  Agent shall have received  counterparts of this Supplement that,
when taken together, bear the signatures of the New Guarantor and the Collateral
Agent.  Delivery of an executed  signature page to this  Supplement by facsimile
transmission   shall  be  as  effective  as  delivery  of  a  manually  executed
counterpart of this Supplement.

                  SECTION  4.  Except  as  expressly  supplemented  hereby,  the
Guarantee Agreement shall remain in full force and effect.

                  SECTION 5. THIS SUPPLEMENT SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                  SECTION 6. In case any one or more of the provisions contained
in this  Supplement  should be held  invalid,  illegal or  unenforceable  in any
respect,  the validity,  legality and enforceability of the remaining provisions
contained herein and in the Guarantee Agreement shall not in any way be affected
or impaired  thereby (it being  understood  that the  invalidity of a particular
provision hereof in a particular  jurisdiction shall not in and of itself affect
the validity of such  provision in any other  jurisdiction).  The parties hereto
shall  endeavor in good-faith  negotiations  to replace the invalid,  illegal or
unenforceable  provisions  with valid  provisions  the economic  effect of which
comes as close as  possible  to that of the  invalid,  illegal or  unenforceable
provisions.

                  SECTION 7. All  communications  and notices hereunder shall be
in writing and given as provided in Section14 of the Guarantee  Agreement.  All
communications  and notices  hereunder to the New Guarantor shall be given to it
at the address set forth under its signature below, with a copy to the Borrower.




                  SECTION  8.  The  New   Guarantor   agrees  to  reimburse  the
Collateral  Agent  for  its  out-of-pocket  expenses  in  connection  with  this
Supplement,  including the reasonable fees,  disbursements  and other charges of
counsel for the Collateral Agent.


                  IN WITNESS WHEREOF, the New Guarantor and the Collateral Agent
have duly executed this Supplement to the Guarantee  Agreement as of the day and
year first above written.


                                     [Name Of New Guarantor],

                                       by

                                         Name:
                                         Title:
                                         Address:





                                     CREDIT SUISSE, as Collateral Agent,

                                       by

                                         Name:
                                         Title:

                                       by

                                         Name:
                                         Title: