EXHIBIT 10.5
                                    GUARANTY

                  THIS  UNLIMITED  GUARANTY OF PAYMENT (as defined in Section 15
hereof,  ALONG  WITH ALL  OTHER  DEFINED  TERMS,  this  "Guaranty")  is made and
effective  as of October  20,  2000 by and among  TALK.COM  INC.  (as more fully
defined below,  "Guarantor") in favor of MCG FINANCE  CORPORATION (as more fully
defined below, "Administrative Agent"), as Administrative Agent for the Lenders.

                                 R E C I T A L S

                  WHEREAS,  Borrowers,  Administrative  Agent and  Lenders  have
entered into (or substantially contemporaneously herewith are entering into) the
Credit  Agreement  and  other  Loan  Documents  pursuant  to which  Lenders  are
extending credit to Borrowers on a senior secured basis; and

                  WHEREAS, Guarantor is the sole shareholder of TALK.COM HOLDING
CORP.  and  ACCESS  ONE  COMMUNICATIONS  CORP.,  which  entities  are two of the
Borrowers under the Loan Documents; and

                  WHEREAS, to induce Administrative Agent and Lenders to perform
under the Loan Documents,  Guarantor has agreed to guaranty the Liabilities upon
and subject to the terms of this Guaranty; and

                  WHEREAS,  Guarantor has determined  that Guarantor will derive
substantial  direct and indirect benefits from the extension of credit under the
Loan Documents;

                  NOW,  THEREFORE,  for good  and  valuable  consideration  (the
receipt and sufficiency of which are hereby  acknowledged),  and intending to be
legally bound hereby,  Guarantor and Administrative  Agent each hereby agrees as
follows:

         1.       Nature  of   Guaranty.   Guarantor   hereby   unconditionally,
absolutely and completely  guarantees to each Lender and to Administrative Agent
(for the  benefit of each  Lender) the full and timely  payment  when due of all
Liabilities and the full and timely  performance of all other  Obligations under
the Loan Documents.  This Guaranty is a guaranty of payment and performance (and
not a guaranty of  collection).  This Guaranty is a continuing  and  irrevocable
guaranty until terminated in accordance with Section 3. All Liabilities shall be
conclusively  presumed to have been created,  incurred,  extended,  accepted and
continued  by each  Lender  and  Administrative  Agent  in  reliance  upon  this
Guaranty.  GUARANTOR  HEREBY  DESIGNATES  ALL  OF  ITS  OBLIGATIONS  UNDER  THIS
GUARANTY,  INCLUDING, WITHOUT LIMITATION, ITS OBLIGATIONS TO PAY ALL LIABILITIES
AND TO  PERFORM  ALL  OBLIGATIONS  OF  BORROWERS  UNDER THE LOAN  DOCUMENTS,  AS
"DESIGNATED  SENIOR  DEBT"  UNDER  (AND AS  DEFINED  IN) THE  SUBORDINATED  NOTE
INDENTURES FOR ALL PURPOSES THEREUNDER.

         2.       Payments Under Guaranty.  Upon any demand from time to time to
Guarantor  by  Administrative  Agent  during the  occurrence  of any Default (as
defined in the Credit  Agreement),


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Guarantor  will  immediately  pay and  remit to  Administrative  Agent  (for the
ratable  benefit of Lenders) such of the  Liabilities  as  Administrative  Agent
determines  to be then due under the Loan  Documents  (or that could be then due
but for a defense thereto by a Borrower). All payments under this Guaranty shall
be made by Guarantor in U.S. Dollars in immediately  available funds and without
any  condition,  deduction,  offset,  netting,  counterclaim  or  reservation of
rights.

         3.       Termination;  Reinstatement. This Guaranty shall terminate and
be of no further  force or effect upon the  occurrence  of both of the following
two events: (a) the indefeasible and unconditional payment in full of all of the
Liabilities, and (b) the termination of the Credit Agreement (in accordance with
its terms).  Upon any such  termination,  Administrative  Agent (at  Guarantor's
request  and  expense)  will  execute  and  deliver to  Guarantor  (without  any
representation,  warranty,  recourse,  indemnification  or liability of any kind
whatsoever)  such documents as Guarantor may  reasonably  request and provide to
Administrative   Agent  to  evidence  such  termination.   Notwithstanding   the
foregoing,  if any payment made by or on behalf of any Borrower  respecting  any
Liability (or any portion of any such payment) at any time after the termination
of this Guaranty  shall be required to be repaid or refunded in compliance  with
any  applicable  state or federal law  (including  the United States  Bankruptcy
Code)  or  any  order  of a  court  of  competent  jurisdiction,  then  (1)  the
Liabilities  shall be deemed not to have been  indefeasibly  paid in full to the
extent of such repayment or refund so made, and (2) the obligations of Guarantor
under this Guaranty  shall be  reinstated  and continue in full force and effect
until the conditions for  termination  hereof have been  satisfied,  and (3) the
Person who repaid or refunded such payment (whether or not it is  Administrative
Agent) shall be entitled to the full benefits of this Guaranty,  notwithstanding
any prior  termination of this Guaranty or the cancellation of any note or other
agreement evidencing the Liabilities.

         4.       Collateral  for   Obligations.   Guarantor  agrees  that  this
Guaranty  (unless  expressly  otherwise  agreed  to by  Administrative  Agent in
writing) will be secured by all  collateral  and credit  enhancements  hereafter
pledged,  collaterally  assigned or otherwise encumbered to Administrative Agent
by  Guarantor,  whether  or not such  encumbrance  specifically  relates  to the
Liabilities.  At any time upon the  request of  Administrative  Agent and at the
expense  of  Guarantor,  BUT ONLY if and to the extent  that any such  requested
grant of collateral would not require the consent or approval of America Online,
Inc.  ("AoL"),  then  Guarantor  shall grant a security  interest in,  pledge of
and/or  otherwise  encumber any or all of its assets in favor of  Administrative
Agent (for the benefit of Lenders) as collateral support for this Guaranty.

         5.       Subrogation   and   Subordination.   Until  this  Guaranty  is
terminated  in  accordance  with Section 3, then  Guarantor  shall not assert or
pursue any claim,  remedy or other  right  that  Guarantor  at any time may have
against any Borrower or other guarantor that arises from the existence, payment,
performance or enforcement of Guarantor's obligations under this Guaranty or any
other  Loan  Document,  including  any  right  of  subrogation,   reimbursement,
contribution,  exoneration,  or indemnification,  or any right to participate in
any claim or remedy of  Administrative  Agent or any Lender against any Obligor,
or any right or claim to any collateral that Administrative  Agent or any Lender
at any time may have an interest in, whether or not such claim,  remedy or right
arises  under  contract,  organic  document,  statute,  common law or in equity.
Moreover,  until this Guaranty is terminated in accordance  with Section 3, then
except as otherwise expressly permitted hereunder, under the Credit Agreement or
by  Administrative  Agent  in  a  separate  writing,  (a)  any  indebtedness  or
obligation  of any  Borrower  or other  guarantor  to or in  favor of  Guarantor
(whether  evidenced by a promissory  note,  an  inter-corporate  ledger entry or
otherwise) is and shall be


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subordinate,  junior and  subject  in right of  payment to the prior  payment to
Administrative   Agent   (unconditionally   and  indefeasibly)  of  all  of  the
Liabilities,  and (b) no such  indebtedness  or obligation may be secured by any
pledge, lien or other encumbrance on or of any property of any Borrower or other
guarantor,  and (c) Guarantor shall not take, receive, accept or demand from any
Borrower or other guarantor (by set-off, recoupment,  litigation or in any other
manner) payment of the whole or any part of such indebtedness or obligation.

         6.       Enforcement;  Waivers of Suretyship  Defenses and  Marshaling.
Guarantor agrees that Administrative  Agent and/or Lenders may pursue,  enforce,
preserve,  waive  and/or  release any rights,  claims and  remedies  against any
Borrower or other Obligors  (including  other  guarantors) who are in any manner
liable on any  Liability  (and/or  against  any  collateral  security  or credit
enhancement  therefor)  in any  order or  manner  that  Administrative  Agent or
Lenders determine, and no such action shall affect in any manner the obligations
of Guarantor hereunder.  Guarantor hereby waives any and all defenses and rights
of discharge based upon suretyship  and/or  impairment of collateral  (including
any lack of attachment,  perfection  and/or  enforcement with respect thereto or
any  release  thereof)  that  Guarantor  at any time may have  with  respect  to
Administrative  Agent  or any  Lender  or  with  respect  to any of  Guarantor's
obligations  hereunder or under any other  agreement  that Guarantor at any time
may enter into with  Administrative  Agent or any Lender. No modification to and
no invalidity,  irregularity or unenforceability (temporary or otherwise) of any
Liability  against any Borrower or other Obligor (or any collateral  security or
credit enhancement for any such Liability) shall be a defense to the performance
and  enforcement  of the  obligations  under this Guaranty,  including  (without
limitation) any failure of consideration,  absence of  authorization,  breach of
warranty,  payment,  fraudulent  conveyance,   statute  of  frauds,  statute  of
limitations,  accord and  satisfaction,  insolvency,  bankruptcy  and/or  usury.
Guarantor  agrees that,  upon the  occurrence  of any Event of Default under the
Loan Documents,  Administrative  Agent shall have the immediate right to enforce
and realize  upon (or forbear  therefrom)  any and all  collateral  security and
credit  enhancements  (including this Guaranty) granted under the Loan Documents
in any manner or order that  Administrative  Agent deems  expedient or in its or
Lenders' best interest without regard to any equitable  principles of marshaling
or otherwise.

         7.       Waivers of Notices.  Guarantor  waives notice of acceptance of
this Guaranty,  notice of the incurrence of any of the Liabilities  from time to
time, and notice of any extension,  renewal, refunding,  refinancing,  increase,
modification and/or  restructuring of any Liability from time to time. Guarantor
also waives  notice of any default  with  respect to any  Liability or otherwise
under the Loan Documents, and any notice of acceleration or other pursuit of any
remedies under the Loan Documents (other than against Guarantor).

         8.       Access to  Information by Guarantor.  Guarantor  represents to
Administrative  Agent and each Lender that  Guarantor (a) has adequate  means to
obtain from  Borrowers on a continuing  basis  information  concerning  the Loan
Documents and the financial condition of Borrowers,  and (b) is not relying upon
Administrative Agent or any Lender to provide any such information either now or
in the future.

         9.       Credit  Report  Authorizations.  Guarantor  hereby  authorizes
Administrative  Agent  from time to time (at  Administrative  Agent's  election)
(a) to  obtain,  review and use credit  reports  on  Guarantor  and/or any other
information  relating  to the  creditworthiness  of  Guarantor  from any  credit
reporting  agency or other  third party and (b) to share such  information  with
each Lender


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<PAGE>

and Administrative Agent's and each Lender's Affiliates,  counsel,  advisors and
agents  for use in  connection  with  the Loan  Documents  (but  subject  to any
restrictions  and limitations on such use or disclosure as set forth in the Loan
Documents).

         10.      Additional  Guarantor  Covenants.   Guarantor  hereby  further
covenants  and agrees that,  until this  Guaranty is  terminated  as provided in
Section  3,  Guarantor  will  comply  with  the  following   covenants   (unless
Administrative  Agent otherwise  consents in writing,  which consent will not be
unreasonably withheld, delayed or conditioned while no Default is occurring):

                  a. Disclosure  Schedules.  Attached hereto as Schedule 10 is a
set of Schedules describing the assets,  operations and performance of Guarantor
and its Subsidiaries (other than Borrowers) that would be required under Article
3 of the  Credit  Agreement  if  Guarantor  were a  "Borrower"  thereunder  (and
Guarantor  hereby  represents that such Schedule is accurate and complete in all
material respects). From time to time upon the written request of Administrative
Agent (which request shall not be made more frequently than once every 12 months
unless an Event of  Default  exists),  Guarantor  will  prepare  and  deliver to
Administrative   Agent  an  updated  chart  of   Guarantor's   equity  and  debt
capitalization and an updated list of material contracts,  intellectual property
(whether  owned or licensed,  but excluding  mass market  software),  regulatory
licenses (if any), real estate (whether owned or leased), subsidiaries, material
litigation,  and all on-going  transactions or relationships  with any Borrower.
For  purposes  of this  Section,  a  "material  contract"  includes  only  those
agreements  and  contracts  the loss or  breach of which  could  have or cause a
Material  Adverse  Effect and  "material  litigation"  includes only those legal
proceedings that, if adversely resolved,  could have or cause a Material Adverse
Effect.

                  b. Other Information;  Further Assurances.  From time to time,
Guarantor  shall  provide   Administrative  Agent  with  any  other  information
(financial or otherwise) reasonably requested by Administrative Agent. From time
to time,  upon request by  Administrative  Agent,  Guarantor  shall  execute and
deliver (or shall cause to be  executed  and  delivered)  such  supplements  and
modifications to and/or replacements of this Guaranty and such further documents
as may be reasonably  required to effectuate or implement the intentions of this
Guaranty (or to otherwise facilitate the performance hereof).

                  c. Compliance with Laws. Guarantor will comply in all material
respects with all material laws, rules, regulations and orders (federal,  state,
local and otherwise) that are applicable to Guarantor.

                  d. Transactions with Borrowers. Except to the extent otherwise
expressly permitted  hereunder,  under the Credit Agreement or by Administrative
Agent in a separate writing,  Guarantor will not (1) enter into any agreement or
engage in any  transaction  with any  Borrower,  or (2)  receive  or accept  any
payment or any other funds  (including  any loans,  dividends or  distributions)
from any  Borrower.  Notwithstanding  the  foregoing,  (i) as and to the  extent
permitted under the Credit Agreement,  Guarantor may make equity  investments in
and  unsecured,  subordinated  loans to any  Borrower  (in each  such  instance,
pursuant to documentation that is in form and substance reasonably acceptable to
Administrative  Agent),  and (ii)  Guarantor  may  license  to a  Borrower  on a
royalty-free  basis  intellectual  property owned by Guarantor as of the Closing
Date (in each  such  instance,  pursuant  to  documentation  that is in form and
substance  reasonably  acceptable  to  Administrative  Agent).  FOR AVOIDANCE OF
DOUBT,  Guarantor  also shall be  entitled to receive  and


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<PAGE>

accept  payments  and  dividends  from a Borrower  if and to the extent (a) such
Borrower is expressly permitted to make such payments under the Credit Agreement
and (b) either (I)  Guarantor  at the time of such  payment or dividend has less
than $15 million of cash,  immediately  available funds, and readily  marketable
securities or (II) within 10 Business Days after  receiving the proceeds of such
payment  or  dividend,  Guarantor  uses  such  funds  to  make a  payment  on an
obligation to an unrelated third party or returns such funds to such Borrower.

                  e. Liens; Asset Transfers. Guarantor shall not pledge, grant a
security interest in or otherwise encumber or permit any such encumbrance on any
of  Guarantor's  assets or  property  other than (1) in favor of  Administrative
Agent (for the benefit of Lenders) or (2) purchase money security  interests and
capital leases (subject to the same standards, but not limited in amounts, as is
set forth in  Sections  5.2 and 5.5 of the  Credit  Agreement  with  respect  to
purchase  money  security  interests and capital  leases by a Borrower),  or (3)
encumbrances in favor of AoL as set forth in the AoL Investment  Agreements,  or
(4)  encumbrances  listed on  Schedule  10 from time to time with the consent of
Administrative Agent (which consent will not be unreasonably  withheld,  delayed
or  conditioned  while no  Default  is  occurring).  Guarantor  shall  not sell,
transfer,   lease,  license  on  an  exclusive  basis  (without  retaining  such
Borrower's and its assigns'  absolute  right to use on a royalty-free  basis) or
otherwise  dispose of ANY material  asset other than (a) the stock and/or assets
of  Compco,  Inc.  and (b) assets  disposed  of  pursuant  to  transactions  for
reasonably fair value received under the  circumstances  that do not involve (i)
any ownership  interest in, any claim against or any  indebtedness or obligation
of any Borrower or (ii) any asset that is used in connection  with the operation
of any Borrower.

                  f. Dividends,  Distributions and Redemptions.  Guarantor shall
not declare or make any payment of any kind with respect to any equity  interest
of Guarantor (including with respect to options and warrants therefor),  whether
as a  dividend,  distribution,  redemption,  retirement,  repurchase,  return of
capital or otherwise,  except (as and to the extent  applicable) (i) payments to
and  redemptions  from a Borrower,  and (ii)  payments to and  redemptions  from
Administrative  Agent or any Lender,  and (iii) payments to and redemptions from
AoL in accordance with the AoL Investment  Agreements,  provided,  however, that
any such payment to AoL with respect to  Guarantor's  repurchase of any warrants
or warrant  shares  shall be satisfied  only through the issuance of  additional
stock of  Guarantor  (and not  through a payment of cash or  issuance of a note)
unless  either (I) no Default  then  exists  under the Loan  Documents  or would
otherwise be caused by the payment of such amount to AoL in cash (including, any
Default  under  Section 4.1 on a pro forma basis after  deducting  such proposed
payment  from OCF) or (II)  Administrative  Agent (with the approval of Lenders)
otherwise consents thereto, and (iv) redemptions from departing employees as and
to the  extent  approved  by  Guarantor's  board  of  directors,  and  (v)  such
redemptions  as from  time to time  may be  approved  by  Administrative  Agent.
Notwithstanding  the  foregoing,  Guarantor  from  time to time may  redeem  and
otherwise  satisfy  indebtedness  (whether or not convertible  into equity) at a
price not to exceed par.

                  g. Access.  Guarantor (upon Administrative  Agent's reasonable
request  from  time  to  time)  will  use  commercially  reasonable  to  provide
Administrative Agent and each Lender (and their representatives and agents) with
reasonable  access  during  normal  business  hours  to  Guarantor's  management
personnel,  books and records,  property and operations (including its financial
records),  whether such  property,  books and records are in the  possession  of
Guarantor or are in the possession of a third party (including the possession of
Guarantor's  Affiliates,  accountants


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<PAGE>

and legal counsel),  provided  however that such efforts to provide access under
this Section shall not require Guarantor to waive any legal privilege  available
to Guarantor with respect to such information.

                  h. Limitation on Activities, Assets and Liabilities of Holding
Company.  Guarantor  shall not (i) engage in any  activity  other  than  owning,
managing and/or providing financing for Borrowers and wholly-owned subsidiaries,
or (ii) own,  lease or license  any assets  other  than  cash,  publicly  traded
investments of investment-grade  quality,  other marketable  securities,  equity
interests  in or  unsecured,  subordinated  loans  to a  Borrower  or a  secured
guarantor  under  the  Loan  Documents,   equity  interests  in  and  unsecured,
subordinated  loans to (to the extent such  interests  and loans exist as of the
Closing Date or are otherwise  permitted  under the Credit  Agreement) any other
wholly-owned subsidiary of Guarantor,  assets owned and leased as of the Closing
Date (including  intellectual  property owned as of the Closing Date, so long as
such  intellectual  property is licensed to Borrowers  on a  perpetual,  royalty
free,  world-wide  basis),  and/or incidental assets,  furniture,  equipment and
leasehold  interests (which  incidental  assets,  in the aggregate,  have a fair
value not in excess of $10 million),  or (iii) create,  establish or acquire any
subsidiaries  (unless  such  subsidiaries  become  either  (at the  election  of
Administrative  Agent) a borrower or secured  guarantor under and subject to the
terms and conditions of the Loan Documents).

                  i.  Independence  of  Covenants.  All  covenants  and defaults
contained  in  this  Guaranty  and the  other  Loan  Documents  shall  be  given
independent  effect. If a particular action or condition is not permitted by any
covenant in this Guaranty,  then the fact that such action or condition would be
permitted by an exception to (or would  otherwise be within the  limitations of)
another covenant in this Guaranty shall not avoid the occurrence or existence of
a Default if such action is taken or if such condition exists.

         11.      Indemnity and Expenses.  Guarantor  hereby agrees to indemnify
and hold Administrative  Agent and each Lender harmless from and against any and
all claims,  losses, and liabilities arising out of or resulting from any of the
following  events (except to the extent such claims,  losses or liabilities  are
directly  caused  by the  gross  negligence,  willful  misconduct  or  fraud  of
Administrative  Agent or any  Lender):  (1)  Guarantor's  failure  to perform or
otherwise observe any of the provisions  hereof, or (2)  Administrative  Agent's
enforcement  of  any  of  the  provisions   hereof,  or  (3)  Guarantor's  gross
negligence,  willful  misconduct  or  fraud.  Upon  demand,  Guarantor  will pay
Administrative  Agent the amount of any and all reasonable  expenses,  including
the  reasonable  fees and  disbursements  of its  counsel and of any experts and
agents, that Administrative Agent or any Lender may incur in connection with any
of the matters  described in the first  sentence of this  Section.  If Guarantor
fails or refuses to pay  Administrative  Agent any amount due  pursuant  to this
Guaranty or to otherwise deliver to  Administrative  Agent any property required
to be delivered pursuant to this Guaranty,  then such amount or, as appropriate,
the fair  market  value of such  property  will  accrue  interest  until paid or
delivered at the rate then otherwise applicable to indebtedness under the Credit
Agreement  (or the maximum  amount  permitted by  applicable  law,  whichever is
less),  and Guarantor  will be obligated to pay such interest to  Administrative
Agent.

         12.      Relationship  to Other  Guaranties.  This  Guaranty  shall not
supersede any earlier guaranty of Guarantor in which Administrative Agent has an
interest  unless  expressly  provided  herein  nor shall any later  guaranty  of
Guarantor  in  which  Administrative  Agent  has an  interest  be  construed  to
supersede this Guaranty unless expressly provided therein.


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<PAGE>

         13.      Entire  Agreement;  Parol Evidence.  With the exception of the
Loan  Documents and any other  guaranty  agreement of  Guarantor,  this Guaranty
contains  the entire  understanding  and  agreement  between the parties  hereto
concerning   the  subject  matter  hereof  and  supersedes  any  and  all  prior
understandings  and  agreements,  whether  oral or written  between  the parties
respecting the subject matter hereof.  Guarantor represents and warrants that no
other oral or written representations, warranties, promises or agreements of any
kind or nature whatsoever have been made by Administrative Agent to Guarantor in
connection herewith, either directly or indirectly. No course of dealing, course
of  performance or trade usage,  and no parol  evidence of any nature,  shall be
used to  supplement  or  modify  any of the  terms  hereof,  nor are  there  any
conditions to the full effectiveness of this Guaranty.

         14.      Successors  and  Assigns.  This  Guaranty  shall  inure to the
benefit of and may be enforced by Administrative Agent, its successors, assigns,
participants, pledgees and transferees.

         15.      Selected Relevant Definitions.  For purposes of this Guaranty,
the following terms have the following corresponding meanings (otherwise, unless
the  context  otherwise  requires,  then  terms used in this  Guaranty  have the
meanings provided in the Credit Agreement):

                  a.  "Affiliate"  of any  Person  means any other  Person  that
directly or indirectly controls, is controlled by or is under direct or indirect
common control with such Person.  A Person shall be deemed to "control"  another
Person if such first Person directly or indirectly possesses the power to direct
(or to cause the direction of or to materially  influence)  the  management  and
policies  of  the  second  Person,  whether  through  the  ownership  of  voting
securities,  by contract or otherwise.  Without  limiting the  generality of the
foregoing,  each of the following Persons will be deemed to be an Affiliate of a
Person:  (a) each  Person who owns or controls 5% or more of any class or series
of any equity interest of such Person,  and (b) each member,  manager,  partner,
director  and/or  senior  executive  officer  of such  Person  or any  Affiliate
thereof,  and (c) any  family  member or other  relative  of such  Person or any
Affiliate thereof, and (d) any trust of which any Person or Affiliate thereof is
either  a  trustee  or  beneficiary.   Notwithstanding  the  foregoing,  neither
Administrative  Agent  nor any  Lender  shall be deemed  to be an  Affiliate  of
Guarantor or any Borrower.

                  b. "Borrowers" means, individually and collectively,  TALK.COM
HOLDING CORP. and ACCESS ONE COMMUNICATIONS  CORP. and the other Borrowers under
and as defined in the Credit  Agreement,  including any  successors or assignees
thereof.

                  c.  "Credit  Agreement"  means that  certain  Credit  Facility
Agreement   dated  as  of  October  20,  2000  (as  the  same  may  be  amended,
supplemented,  restated,  replaced,  extended,  increased and otherwise modified
from time to time)  pursuant to which Lenders are extending  credit to Borrowers
on a senior secured basis.

                  d.  "Guarantor"  or  "Guarantors"   means,   individually  and
collectively,  each party  that is at any time  obligated  under this  Guaranty,
including any successor,  permitted assignee,  heir, executor,  administrator or
personal representative thereof.

                  e. "Guaranty" means this Guaranty as may be amended, modified,
supplemented, replaced and substituted from time to time hereafter.


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<PAGE>

                  f. "Lenders" means, individually and collectively, each Lender
under and as  defined  in the  Credit  Agreement,  including  any  successor  or
assignee thereof.

                  g.  "Liability"  or  "Liabilities"  means,   individually  and
collectively, each and all obligations of any Borrower and any other Obligor (as
defined  in the Credit  Agreement)  to pay  principal,  interest,  fees,  costs,
indemnities, contribution obligations, protective advances and other amounts and
compensation  from  time to time due  under  the Loan  Documents,  whether  such
obligation  is direct or  indirect,  liquidated  or  unliquidated,  absolute  or
contingent,  joint,  several or joint and  several,  and whether now existing or
hereafter arising, due or to become due and whether or not originally contracted
with  Administrative  Agent or any Lender,  including  indebtedness  acquired by
Administrative  Agent or any Lender  through  whole or partial  assignment of an
item that would be a  Liability  if  created  directly  between a  Borrower  and
Administrative  Agent  or  any  Lender.  Without  limiting  the  foregoing,  the
Liabilities  shall  include  any  and  all  increases,   extensions,   renewals,
refinancings and refundings of the Liabilities.

                  h. "Loan  Documents"  means the Credit Agreement and the other
Loan Documents (as defined in the Credit Agreement), as the same may be amended,
supplemented,  restated,  refinanced,  replaced, extended and otherwise modified
from time to time.

                  i.  "Subordinated  Note  Indentures"  means  each  of (1)  the
indenture  dated as of September 9, 1997 between  Guarantor  and U.S. Bank Trust
National  Association  (formerly  known as First  Trust  of New  York,  National
Association),  as trustee,  and (2) the indenture  dated as of December 10, 1997
between  Guarantor and U.S. Bank Trust National  Association  (formerly known as
First Trust of New York,  National  Association),  as trustee,  in each case, as
amended,  supplemented,  amended and restated or otherwise modified from time to
time.

         16.      Miscellaneous.

                  a. Loan  Document.  This Guaranty is a Loan Document  executed
pursuant to the Credit  Agreement  and  (unless  otherwise  expressly  indicated
herein) is to be  construed,  administered  and applied in  accordance  with the
terms and provisions thereof.

                  b. Confidentiality of Information.  Administrative Agent shall
maintain the confidentiality of all non-public  information concerning Guarantor
delivered to  Administrative  Agent pursuant to the Loan Documents as and to the
extent such confidentiality would be required with respect thereto under Section
10.5 of the Credit Agreement if Guarantor were a "Borrower" thereunder.

                  c.  Amendments.  No amendment to or waiver of any provision of
this Guaranty,  nor any consent to any departure by Guarantor herefrom,  will be
effective  unless such amendment,  waiver or consent is in writing and signed by
Administrative Agent and Guarantor. Any such waiver or consent will be effective
only in the  specific  instance  and for the  specific  purpose  for which it is
given.

                  d.  Notices.  Any notice,  request,  consent,  waiver or other
communication  required or permitted  under or in connection  with this Guaranty
will be deemed  satisfactorily given if it is in writing and is delivered either
personally to the addressee thereof, or by prepaid registered or


                                       8
<PAGE>

certified U.S. mail (return receipt  requested),  or by a nationally  recognized
commercial  courier  service  with  next-day  delivery  charges  prepaid,  or by
telegraph,  or by facsimile (voice confirmed),  or by any other reasonable means
of personal delivery to the party entitled thereto at its respective address set
forth  below its  signature  to this  Guaranty.  If any party fails to insert an
address  below,  then such failure shall  constitute a  designation  of its last
known  address as the address for all notices and  communications.  Any party to
this Guaranty may change its address or facsimile  number for notice purposes by
giving  notice  thereof  to the other  parties  hereto in  accordance  with this
Section,  provided that such change shall not be effective until 2 calendar days
after notice of such change. All such notices and other  communications  will be
deemed  given and  effective  (a) if by mail,  then  upon  actual  receipt  or 5
calendar days after mailing as provided above (whichever is earlier),  or (b) if
by  facsimile,  then upon  successful  transmittal  to such  party's  designated
number,  or (c) if by  telegraph,  then upon actual  receipt or 2 Business  Days
after  delivery to the telegraph  company  (whichever is earlier),  or (d) if by
nationally  recognized commercial courier service, then upon actual receipt or 2
Business Days after delivery to the courier service (whichever is earlier),  (e)
or if otherwise delivered, then upon actual receipt.

                  e.  Headings.  The various  headings used in this Guaranty are
for  convenience  of  reference  only,  and  shall not  affect  the  meaning  or
interpretation of this Guaranty or any provision hereof.

                  f.  Governing  Law.  This  Guaranty  shall be  governed by and
construed in accordance  with the internal laws of the  Commonwealth of Virginia
(exclusive of its choice of law rules).

                  g.  Counterparts.  This  Guaranty  may be  executed in several
counterparts;  each of which shall be deemed an original, but all of which shall
constitute one and the same instrument.

                  h.  Severability.  Wherever  possible,  each provision of this
Guaranty  shall be interpreted in such manner as to be effective and valid under
applicable  law. If any  provision of this  Guaranty  shall be  prohibited by or
invalid under such law, then such  provision  shall be ineffective to the extent
of such  prohibition or invalidity,  without  invalidating the remainder of such
provision or the remaining provisions of this Guaranty.

                  i.  Estoppel  Certificates  and  Replacement  Agreements.   In
connection with any subsequent sale, assignment, participation or other transfer
or refinancing of the  Liabilities  (or any portion  thereof) by  Administrative
Agent or any  Lender or at any other time  requested  by  Administrative  Agent,
Guarantor within 10 calendar days of receiving a request by Administrative Agent
will provide a certificate  in form and  substance  reasonably  satisfactory  to
Administrative  Agent confirming,  among other items, the following  information
(if and to the extent then true):  (1) that this Guaranty  remains in full force
and effect,  and (2) that there exist no defaults  under this  Guaranty or under
any  agreements  between  Guarantor and any other Obligor (or any  circumstances
that with the passage of time or the giving of notice, or both, might constitute
a  default  hereunder  or  thereunder),  and (3) that  there  exist no  offsets,
counterclaims  or other  adjustments in favor of Guarantor  under this Guaranty.
Moreover, in connection with any subsequent sale,  assignment,  participation or
other  transfer or  refinancing of the Loan  Documents,  the  Liabilities or any
other indebtedness of any Borrower to Administrative Agent or any Lender (or any
portion  thereof),


                                       9
<PAGE>

Guarantor,  if requested by Administrative  Agent, will concurrently  execute in
favor of the transferee or refinancing lender a guaranty  substantially  similar
in form and substance to this Guaranty.

                  j. WAIVER OF  LIABILITY.  Guarantor  (a) agrees  that  neither
Administrative  Agent  nor any  lender  (nor any of their  directors,  officers,
employees or agents) shall have any liability to guarantor  (whether sounding in
tort,  contract  or  otherwise)  for losses or costs  suffered  or  incurred  by
guarantor  in  connection  with  or in  any  way  related  to  the  transactions
contemplated or the relationship  established by any Loan Document,  or any act,
omission or event  occurring in  connection  herewith or  therewith,  except for
foreseeable actual losses resulting directly from Administrative Agent's or such
lender's own gross negligence,  willful misconduct or fraud (including the gross
negligence,   willful  misconduct  or  fraud  of  its  directors,  officers  and
employees) and (b) waives, releases and agrees not to sue upon any claim against
Administrative Agent or any Lender (or their directors,  officers,  employees or
agents) whether sounding in tort,  contract or otherwise,  except for claims for
foreseeable actual losses resulting directly from administrative agent's or such
lender's own gross negligence,  willful misconduct or fraud (including the gross
negligence,   willful  misconduct  or  fraud  of  its  directors,  officers  and
employees). Moreover, whether or not such damages are related to a claim that is
subject  to the  waiver  effected  above  and  whether  or not  such  waiver  is
effective,  neither  Administrative  Agent nor any lender (nor their  directors,
officers,  employees or agents)  shall have any  liability  with respect to (and
Guarantor hereby waives,  releases and agrees not to sue upon any claim for) any
special, indirect,  consequential,  punitive or non-foreseeable damages suffered
by  guarantor  in  connection  with or in any way  related  to the  transactions
contemplated or the relationship  established by any Loan Document,  or any act,
omission or event occurring in connection herewith or therewith.

                  k. FORUM SELECTION; CONSENT TO JURISDICTION. Any litigation in
connection  with or in any way  related to any loan  document,  or any course of
conduct, course of dealing,  statements (whether verbal or written),  actions or
inactions of  Administrative  Agent, any Lender or Guarantor will be brought and
maintained  exclusively in the courts of the  Commonwealth of Virginia or in the
United States  District  Court for the Eastern  District of Virginia;  provided,
however, that any suit seeking enforcement against guarantor,  any Collateral or
any other property may also be brought (at  Administrative  Agent's and Lenders'
option) in the courts of any other  jurisdiction  where such Collateral or other
property may be found or where  Administrative Agent or any lender may otherwise
obtain personal  jurisdiction  over Guarantor.  Guarantor  hereby  expressly and
irrevocably  submits to the  jurisdiction  of the courts of the  Commonwealth of
Virginia and of the United  States  District  Court for the Eastern  District of
Virginia  for  the  purpose  of any  such  litigation  as set  forth  above  and
irrevocably agrees to be bound by any final and non-appealable judgment rendered
thereby  in  connection  with such  litigation.  Guarantor  further  irrevocably
consents to the service of process by  registered  or  certified  mail,  postage
prepaid,  or by personal service within or outside the Commonwealth of Virginia.
Guarantor  hereby  expressly  and  irrevocably  waives,  to the  fullest  extent
permitted by law, any  objection  which it may have or hereafter may have to the
laying of venue of any such  litigation  brought in any such court  referred  to
above and any claim that any such litigation has been brought in an inconvenient
forum.  To the extent that  Guarantor  has or hereafter may acquire any immunity
from  jurisdiction  of any  court or from any  legal  process  (whether  through
service or notice, attachment prior to


                                       10
<PAGE>

judgment, attachment in aid of execution or otherwise) with respect to itself or
its property,  then guarantor hereby irrevocably waives such immunity in respect
of its obligations under this guaranty.

                  l. WAIVER OF JURY TRIAL. Administrative Agent, each Lender and
Guarantor each hereby knowingly,  voluntarily and  intentionally  waives (to the
maximum  extent not  prohibited by  applicable  law) any rights it may have to a
trial by jury in respect of any  litigation  (whether  as claim,  counter-claim,
affirmative  defense or otherwise)  in connection  with or in any way related to
any of the  Loan  Documents,  or any  course  of  conduct,  course  of  dealing,
statements  (whether verbal or written),  actions or inactions of Administrative
Agent,  any Lender or Guarantor.  Guarantor  acknowledges and agrees (a) that it
has received full and  sufficient  consideration  for this  provision  (and each
other  provision  of each other Loan  Document to which it is a party),  and (b)
that it has been advised by legal counsel in connection  herewith,  and (c) that
this provision is a material inducement for Administrative Agent and each Lender
entering into the Loan Documents and funding Advances thereunder.

                      [BALANCE OF PAGE INTENTIONALLY BLANK]





                                       11
<PAGE>

         IN WITNESS WHEREOF,  this UNLIMITED  GUARANTY has been duly executed by
the parties hereto (through their authorized  officers,  if appropriate),  as an
instrument  under  seal  (whether  or not any such seal is  actually  physically
attached hereto), as of the day and year first above written.

ATTEST:                                     TALK.COM INC., Guarantor



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

[SEAL]                                      Address:    6805 Route 202
                                                        New Hope, PA  18938
                                                        Attn:  General Counsel

                                            Facsimile:  (215) 862-1960


WITNESS:                                    MCG FINANCE CORPORATION (AS
                                            ADMINISTRATIVE AGENT)


                                            By:
---------------------------------------         --------------------------------
                                            Name:    Steven F. Tunney
                                            Title:   COO and CFO

                                            Address:  1100 Wilson Boulevard
                                                      Suite 800
                                                      Arlington, Virginia  22209

                                            Facsimile: (703) 247-7505