BILLING CONCEPTS SYSTEMS, INC.
                            MASTER LICENSE AGREEMENT
















Customer                               Effective Date:


KMC TELECOM HOLDINGS, INC.             _____________________________________


                                       Agreement Number:


                                       _____________________________________




                         BILLING CONCEPTS SYSTEMS, INC.
                            MASTER LICENSE AGREEMENT

      This Master License  Agreement  (this  "License") is made and entered into
this 31st day of December,  1998 (the "Effective  Date"), by and between Billing
Concepts  Systems,  Inc.,  a  Delaware  corporation  ("BCS"),  and  KMC  Telecom
Holdings, Inc., a Delaware corporation ("Customer").

      WHEREAS,  Customer  desires to license from BCS the  proprietary  software
system known as the Modular Business Application  System (the "MBA System"); and

      WHEREAS, BCS has agreed to license the MBA System to Customer,  subject to
the terms and conditions set forth herein;

      NOW, THEREFORE,  in consideration of the mutual promises contained herein,
BCS and Customer agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

     1.1 CURRENT RELEASE shall mean, at any time, the MBA System as described in
the MBA System  Specifications  in effect on the date of the most recent  major,
formal software  release (e.g.,  Version 3.0).  Current Release does not include
modifications  made by BCS  pursuant to an agreement  between BCS and  Customer,
modifications  made by  Customer to the MBA  System,  or  Optional  Applications
Software as defined herein.

     1.2 MBA BASE  SYSTEM  shall mean  Version 3.0 of the MBA System and related
documentation as described in Exhibit A of this License.

     1.3 MBA SYSTEM  shall mean the MBA Base System,  together  with any and all
future  System  Releases,  PTFs and  modifications  that may be  acquired in the
future by  Customer  through  a product  support  agreement  or other  agreement
between BCS and Customer.

     1.4 MBA  SYSTEM  SPECIFICATIONS  shall  mean the  documentation  of the MBA
System on file at BCS' offices in San Antonio,  Texas, and which is delivered to
Customer in Exhibit A. The MBA System  Specifications  also  include the minimum
hardware and software configuration  recommended by BCS for the operation of the
MBA System.

     1.5 PROGRAM TEMPORARY FIX (PTF) shall mean the program and/or documentation
changes and associated installation instructions which at Customer's request are
made available to Customer at no charge in advance of the next System Release to
correct a specific problem reported by Customer during the term of this License.

     1.6 SYSTEM  RELEASE  shall mean a collection  of program and  documentation
changes  (revisions,  deletions  and/or  additions) and associated  installation
instruction  which  are  periodically  made  available  to  Customer  at a price
determined by BCS for the purpose of updating a Current Release to produce a new
Current Release.


                                       2


     1.7 CUSTOMER as used herein shall mean both KMC Telecom Holdings,  Inc. and
any of its  Affiliates.  An  Affiliate  of  Customer  shall mean any entity that
directly  or  indirectly  through  one  or  more  intermediaries   controls,  is
controlled by, or is under common  control with  Customer.  For purposes of this
Section,  "control"  means  the  ownership  of over  50% of the  voting  capital
securities of an entity.


                                   ARTICLE II
                               MBA SYSTEM LICENSE

     2.1  TERM.  The  license  granted  herein  shall  be for a  perpetual  term
commencing as of the Effective Date, and continuing until terminated as provided
herein.

     2.2 GRANT OF LICENSE.  Subject to all of the terms and  conditions  of this
License,  BCS  hereby  grants  to  Customer,  and  Customer  hereby  accepts,  a
nonexclusive,  non-transferable and perpetual license to use the software listed
in Exhibit A of this License (the "Licensed Software").  This License authorizes
the use of the  Licensed  Software  solely  for the  purpose of  processing  its
internal  business  data and/or  external  data as  required  to perform  normal
operations for Customer's  business.  Customer may not use the Licensed Software
for any purpose other than those expressly authorized hereunder.  Customer shall
not:  (i) use the Licensed  Software to act as a service  bureau or provide data
processing  services  to any third  persons;  (ii) make  copies of the  Licensed
Software for distribution to third parties;  (iii) reverse-engineer or decompile
the  Licensed  Software  for  the  purpose  of  designing,   or  developing  for
distribution,  license or sale to third  parties a software  system  competitive
with the  Licensed  Software;  and/or  (iv)  sublicense  or resell the  Licensed
Software or any license rights granted hereunder.


     No transfer of title to the Licensed  Software is effected by this License,
and BCS shall retain sole and exclusive  title to the Licensed  Software and all
modifications thereto and all intellectual property rights associated therewith.

     This  License is limited to use of the  Licensed  Software by Customer  for
processing of Customer's own internal data (and/or  external data as required to
perform  normal  operations  for  Customer's  business)  and  files  at  a  data
processing  facility owned and controlled by Customer or BCS.  Customer may make
copies of the Licensed  Software only for  Customer's  internal use in training,
testing, development, backup and disaster recovery purposes.

     2.3  SUBLICENSING  AND  ASSIGNMENT.  This License may not be sublicensed by
Customer to any other  person,  firm or  organization  without the prior written
consent of BCS.  This License  shall be binding on the parties  hereto and their
respective  successors  and  assigns.  Neither  party may assign or transfer its
rights or obligations  under this License  without the prior written  consent of
the other party,  except that a party may assign this License  without the prior
written  consent of the other  party if such  assignment  is made to a person or
entity  acquiring  substantially  all of the  assets  of such  assigning  party.
Notwithstanding the foregoing,  however,  Customer shall have the right, without
the consent of BCS, to collaterally  assign this License to any lender providing
financing  to  Customer;  provided,  however,  that  any such  assignment  shall
expressly  provide that: (i) Customer shall remain jointly and severally  liable


                                       3


with  the  assignee  for all  obligations  arising  under  this  License  unless
expressly  released  therefrom by BCS; (ii) the assignee  shall have no right to
further  assign this License to any person or entity  without the prior  written
consent of BCS, which shall not be unreasonably  withheld;  and (iii) any breach
by the assignee or Customer of any of the terms of this License shall constitute
a breach  entitling  BCS to terminate  this License as to both  Customer and the
assignee  (subject  to the  conditions  set forth in  Article  III  hereof.  Any
collateral  assignment  by Customer  to a lender  which does not comply with the
conditions of the preceding sentence shall be null and void. Within a reasonable
time after receiving a written  request from Customer,  BCS will issue a consent
to a collateral  assignment of this License to a lender of Customer  without any
further  consideration so long as such collateral  assignment  complies with the
conditions provided herein.

     2.4 LICENSE. Upon the Effective Date, Customer shall pay to BCS the initial
license  fee  referenced  on Exhibit B for the  Licensed  Software.  The initial
license fee shall entitle Customer to use the licensed software components up to
the  capacities  referenced  in  Exhibit  B.  If any of  the  licensed  software
components  are used by  Customer  in excess  of the  capacities  referenced  in
Exhibit B, then Customer shall pay to BCS  additional  license fees as set forth
in Exhibit B.

     2.5  MODIFICATION  OF THE  LICENSED  SOFTWARE.  BCS shall have the sole and
exclusive right to design and develop any derivative works from or modifications
to the Licensed Software. Any and all modifications and/or derivative works made
from the Licensed Software,  including any and all intellectual  property rights
associated therewith, shall be the sole and exclusive property of BCS regardless
of whether those  modifications  or derivative works are prepared at the request
of Customer.

     2.6 USE OF PROPRIETARY  MATERIALS BY CUSTOMER.  Following execution of this
License by BCS and Customer,  BCS shall deliver to Customer certain confidential
and  proprietary   documentation   of  BCS  concerning  the  Licensed   Software
(collectively, the "Confidential Materials"). Customer shall be permitted to use
the Confidential Materials in order to operate the Licensed Software, or for any
other purpose for which Customer has been licensed to use the Licensed Software.
Customer  shall  not be  permitted  to use the  Confidential  Materials  for any
purpose  for  which  Customer  is not  licensed  to use the  Licensed  Software.
Customer  represents  and  warrants to BCS that it will  establish  and maintain
reasonable  procedures to protect the Confidential  Materials from  unauthorized
disclosure or use. Customer shall not disclose the Confidential Materials to any
third persons without the advance written consent of BCS.

     2.7 BCS INSPECTION OF LICENSED SOFTWARE. In order to assure compliance with
the  provisions  of this  License,  BCS and its  representatives,  employees and
agents will have the right to inspect, at BCS' expense,  the use of the Licensed
Software at Customer's site (and at any backup or disaster  recovery sites) from
time to time during normal  business  hours.  Customer will assist BCS in making
such inspections in such manner as BCS may reasonably request.  Such inspections
shall be  conducted  with at least twenty four (24) hours prior notice and shall
not unduly disrupt the conduct of Customer's business.

     2.8 INFRINGEMENT. BCS represents and warrants that BCS is the sole owner of
the MBA  System.  BCS also  represents  and  warrants  that BCS has the right to


                                       4


license the MBA System and that this License does not and will not infringe upon
any United States copyrights, United States patent or other proprietary interest
of any person, firm or organization.

          2.8.1  NOTICE OF CLAIM.  If any action,  claim or suit is  threatened,
brought or made against  Customer  based upon  infringement  of a United  States
copyright,  United States patent,  or other  proprietary right under the laws of
the United  States,  in  connection  with the use of the MBA System by Customer,
Customer  will promptly  notify BCS in writing of such action,  claim or suit of
which it has actual  knowledge and the failure to so notify shall relieve BCS of
its obligations hereunder.

          2.8.2 DEFENSE. BCS shall at BCS' expense take charge of the defense of
any infringement action through attorneys of BCS' selection. If any infringement
action is instituted against BCS and Customer jointly,  BCS will at BCS' expense
defend such action on behalf of both parties. Customer will cooperate at its own
expense in such defense as reasonably  requested by BCS.  Customer will have the
right to  participate  in the defense of such  action,  at  Customer's  expense,
and/or  take its own  position  in any  litigation.  If BCS  appeals  an adverse
decision it will obtain  judicial  relief for Customer or post a bond protecting
Customer from liability for judgment on the adverse  decision  pending the final
determination of the appeal.  BCS will pay in full any settlement  negotiated by
BCS relating to a claim under this Section 2.8, which settlement shall provide a
full release of Customer from all claims.  BCS will  indemnify and hold harmless
Customer of and from all costs and expenses of litigation hereunder,  as well as
the amount of any adverse  judgment  rendered  against Customer as a result of a
finding of  infringement  in favor of any third party as a result of  Customer's
use of the Licensed Software.

          2.8.3 REMEDIAL ACTION. If BCS anticipates an action, claim or suit for
such infringement, or if such an action, claim or suit has been made and the MBA
System, or any part of thereof,  has been held to constitute an infringement and
the use of the MBA  System  or any  part of it is  enjoined,  BCS  will,  at its
expense,  either:  (i) obtain for the  Customer the right to continue to use the
MBA System,  or (ii) replace the MBA System,  or part of the MBA System,  with a
noninfringing   functionally  equivalent  substitute  reasonably  acceptable  to
Customer,   or  (iii)  modify  the  MBA  System  so  as  to  be  non-infringing,
functionally equivalent and reasonably acceptable to Customer.

      A replacement or partial  replacement  of, or a  modification  to, the MBA
System shall be acceptable  to Customer if Customer  remains able to process its
business in substantially  the same manner as before such  replacement,  partial
replacement  or  modification,  and  the  effect  of such  replacement,  partial
replacement  or  modification  is not to require the  expenditure of substantial
additional effort by Customer in the day to day conduct of Customer's business.

      If, however,  BCS is unable,  despite diligent  efforts,  to effect any of
these  options,  Customer  may then  terminate  the  License  granted  herein by
notifying BCS in writing  thereof.  In the event of such  termination,  Customer
shall:

          i.   return the MBA System and all Confidential Materials to BCS; and

          ii.  be relieved of any further  obligation to pay license fees to BCS
               hereunder.

                                       5


      In any event,  BCS agrees to provide  Customer with reasonable  transition
assistance   should  the  License  be   terminated   for  patent  or   copyright
infringement.

          2.8.4  LIMITATION  OF  LIABILITY  FOR  INFRINGEMENT.  BCS will have no
liability  for any claim of  infringement  of copyright,  patent or  proprietary
interest  to the extent  such  claim is based on either  (i) use of any  version
other than the  unmodified  version of the MBA  System,  except as  modified  by
enhancements and pre-release  enhancements  provided by BCS which become part of
the MBA Base System at a later date if  infringement  could have been avoided by
use of such  unmodified  version;  or (ii) use or  combination of the MBA System
with other than BCS provided or approved  programs,  if infringement  could have
been  avoided  by not using the MBA System in  combination  with other than such
programs.

     2.9  CUSTOMER'S  OBLIGATIONS  UPON  TERMINATION.  Upon  termination of this
License for any reason whatsoever, Customer agrees to return to BCS the Licensed
Software and all  Confidential  Materials,  including all copies of object code,
documentation, programs and other materials delivered by BCS under this License,
and to certify to BCS in writing within thirty (30) days after  termination that
Customer  has not  retained  any  copies  of  those  items.  Following  any such
termination,  Customer agrees to cease and permanently  refrain from any and all
use whatsoever of the Licensed Software,  and all Confidential Materials and any
other information supplied by BCS pursuant to this License.

     2.10 SPECIAL WARRANTY AND LIMITATION OF LIABILITY.

          2.10.1  SPECIAL  WARRANTY.  BCS  warrants  that for 90 days  following
installation of the MBA Base System: (i) the MBA Base System will conform in all
material respects to the MBA System Specifications;  and (ii) the media in which
the  Licensed  Software  is  contained  shall  be free of  material  defects  in
materials  and  workmanship.  During the 90 day  warranty  period,  Customer may
request  the  services of BCS to analyze  any  apparent  failure of the MBA Base
System to conform to the MBA System Specifications.  Any failure to conform must
be reported to BCS on a System Problem Report in the format specified by BCS.

On or before July 31,  1999:  (a) BCS shall  install  upgrades to the MBA System
licensed  by Customer  (including  any  enhancements)  which will render the MBA
System Year 2000 Compliant, as defined below; and (b) BCS will provide Customer,
at BCS' expense,  an independent  certification  certifying to such  compliance.
Year 2000 Compliant means that:

(1)   date data from at least 1900 through 2100 will  process  without  error or
      interruption in the MBA System, including leap year calculations; and

(2)   there will be no loss of any  functionality of the MBA System with respect
      to the  introduction,  processing  or output of records  containing  dates
      falling on or after January 1, 2000.

Year 2000 Compliance does not include any processing  failure  resulting from or
related to any operating system software, hardware, microcode,  firmware, system
interface not developed by BCS, or failure of any hardware,  software,  firmware
or other program used in  combination  with the MBA System to properly  exchange
date data with it.

                                       6


The Year 2000  Compliance  Systems(s)  shall be  provided to Licensee as part of
BCS's regular  maintenance and support  services,  subject to Licensee's  timely
payment of maintenance and support fees, except as otherwise provided in Section
5.4 of the Product Support Agreement.

      Customer's  sole and exclusive  remedy for any breach of these  warranties
shall  be to  require  BCS to  cause  the MBA  Base  System  to  conform  to the
applicable System Specifications;  provided, however, that in the event that BCS
cannot  remedy such breach and such failure to so remedy such breach  materially
impacts Customer's  ability to use the Licensed Software,  then BCS shall refund
to Customer all license fees paid for the Licensed  Software on a pro-rata basis
based on a straight line basis over a sixty (60) month period.

BCS' LIABILITY FOR BREACH OF THE WARRANTIES  PROVIDED IN THIS SECTION IS LIMITED
TO THE REMEDIES SET FORTH HEREIN. THE WARRANTIES  PROVIDED HEREIN ARE IN LIEU OF
ANY AND ALL  WARRANTIES,  EXPRESS OR  IMPLIED,  INCLUDING,  BUT NOT  LIMITED TO,
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  BCS
EXPRESSLY  DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR OF FITNESS FOR
A  PARTICULAR  PURPOSE.   THERE  ARE  NO  WARRANTIES  WHICH  EXTEND  BEYOND  THE
DESCRIPTION HEREIN.

          2.10.2 LIMITATION OF LIABILITY.  BCS' LIABILITY TO CUSTOMER UNDER THIS
LICENSE,  SHALL NOT  EXCEED,  AND SHALL BE  LIMITED  TO,  ALL  PAYMENTS  MADE BY
CUSTOMER  UNDER  THIS  LICENSE.  BCS WILL NOT BE LIABLE  FOR ANY  OTHER  DAMAGES
HEREUNDER,  INCLUDING,  BUT NOT LIMITED TO, INCIDENTAL DAMAGES,  LOSS OF PROFITS
AND OTHER  CONSEQUENTIAL  DAMAGES AND ANY CLAIMS OR DEMANDS AGAINST  CUSTOMER BY
ANY OTHER PARTY, EVEN IF BCS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


                                  ARTICLE III
                                  TERMINATION

     3.1 TERMINATION FOR CAUSE. In the event that Customer breaches the terms of
this License by making any unauthorized use of the Licensed Software or engaging
in any other  conduct  which  could  impair  BCS'  copyrights  and  intellectual
property rights in the Licensed  Software,  then following five (5) days' notice
of such breach by BCS and  failure of  Customer to cure such breach  within such
five (5) day period,  BCS shall have the right to terminate this License without
notice  immediately and require Customer to return to BCS the Licensed Software,
all Confidential Materials, and all object code and documentation.  In the event
of any other kind of  material  breach of this  License by either  party  hereto
(except for  nonpayment  by Customer  which is controlled by Section 3.2 of this
License),  and the  breaching  party fails to cure such breach within sixty (60)
days after its receipt of a written notice  specifying the details of the breach
or, with respect to any material breach which cannot  reasonably be cured within
sixty days,  should the  breaching  party fail to proceed  within  sixty days to
commence  curing the breach and  thereafter to proceed with all due diligence to
cure the  breach,  the party not in breach of this  License may  terminate  this
License by giving prompt written notice of termination.


                                       7


     3.2 TERMINATION FOR NONPAYMENT. In the event that Customer fails to pay all
amounts due BCS in accordance with the terms of this License, then following ten
(10) days' notice of such breach by BCS and failure to remedy such breach within
such ten (10) day period,  BCS may terminate this License upon written notice to
Customer.

     3.3  TERMINATION  DUE TO  INSOLVENCY.  In the  event  either  party to this
License  becomes or is declared  insolvent,  becomes  subject to a voluntary  or
involuntary  bankruptcy or similar  proceeding,  or makes an assignment  for the
benefit of all or  substantially  all of its  creditors,  then in such event the
other party to this License may terminate  this License by giving written notice
thereof to such party which notice shall specify the date of termination.

     3.4 BANKRUPTCY OF BCS. In the event that BCS becomes  subject to bankruptcy
proceedings,  this License shall continue in full force and effect, and Customer
shall  continue to enjoy all License rights granted herein subject to Customer's
continued  compliance with all of the terms and conditions of this License.  BCS
acknowledges that if BCS as a  debtor-in-possession  (or a trustee in bankruptcy
in a case under the United States  bankruptcy  code) rejects this License or any
agreement  supplementary  hereto,  Customer may elect to retain its rights under
this License or any agreement supplementary hereto as provided in Section 365(n)
of the bankruptcy code.

Upon written  request of the Customer to BCS or the bankruptcy  trustee,  BCS or
such  bankruptcy  trustee  shall not  interfere  with the rights of  Customer as
provided in this  License or any  agreement  supplementary  hereto to obtain the
Confidential  Materials  from  BCS or  the  bankruptcy  trustee  and  shall,  if
requested,  cause a copy of the  Confidential  Materials to be made available to
Customer at no additional charge.

                                   ARTICLE IV
                    OWNERSHIP OF PROGRAMS, CONFIDENTIALITY
                                AND AUDIT RIGHTS

     4.1  ACKNOWLEDGMENT  OF  INTELLECTUAL  PROPERTY  RIGHTS AND TRADE  SECRETS.
Customer acknowledges that the Licensed Software (including, without limitation,
the database,  data model and any  modifications  to the MBA System and any work
product of BCS which is related to the MBA  System) is a  commercially  valuable
proprietary product of BCS, the design and development of which has involved the
expenditure of substantial  amounts of money and the use of skilled  development
experts over a long period of time and which affords BCS a commercial  advantage
over  its  competitors,  and  that  loss of this  competitive  advantage  due to
unauthorized disclosure or use of such proprietary information would cause great
injury  and  harm to BCS.  Customer  acknowledges  that  the  Licensed  Software
(specifically   including,  but  not  limited  to,  the  documentation  thereof)
constitute intellectual property and TRADE SECRETS, disclosed to Customer on the
basis of the  confidential  relationship  between  Customer  and BCS under  this
License,  to be  used  only  as may be  expressly  permitted  by the  terms  and
conditions of this License,  and that the restrictions  imposed upon Customer by
this  Section  4.1 are  necessary  to protect  the  secrecy of such  proprietary
information and prevent the occurrence of such injury and harm to BCS.


                                       8


Customer  covenants that it will not,  without the prior written consent of BCS,
disclose,  divulge, publish to others or employ to its own advantage, other than
as herein provided, the Licensed Software or any proprietary  information of BCS
relating  thereto  and  that it will  reveal  the  same  only  to  those  of its
employees, employees of Customer's affiliates, attorneys or auditors who require
it for the purpose of Customer's use of the Licensed Software hereunder and only
if such  employees,  attorneys  or auditors  are  subject to use and  disclosure
restrictions as complete as those assumed by Customer hereunder.

The obligations of Customer in this Section 4.1 shall survive any termination of
this License.

     4.2   CONFIDENTIALITY.   BCS  and  Customer  agree  that  all   proprietary
information in whatever form delivered by one party to the other shall be deemed
of  proprietary  and trade secret status and shall be held in strict  confidence
and  shall be used only for  purposes  of this  License.  Each  party  agrees to
exercise  at least  the same  standard  of care to  protect  the  other  party's
proprietary  information  as  is  used  to  protect  its  own  such  proprietary
information  from  unauthorized  disclosures  (but  no  less  than a  reasonable
standard of care).  No such  information  shall be  disclosed  by the  recipient
party,  its agents or employees  without the prior written  consent of the other
party, except as may be necessary to enforce this License or by reason of legal,
accounting  or  regulatory  requirements  beyond the  reasonable  control of the
recipient party.  Notwithstanding the foregoing,  proprietary  information shall
not include such information that: (a) is or becomes generally  available to the
public other than as a result of a disclosure by the receiving  party; (b) is or
becomes  available to the  receiving  party on a  non-confidential  basis from a
source (other than the disclosing party or one if its agents, representatives or
employees) that is not prohibited  from disclosing such  information by a legal,
contractual or fiduciary obligation;  or (c) was known to the receiving party on
a  non-confidential  basis prior to its disclosure to the receiving party by the
disclosing  party.  The provisions of this Section shall survive  termination of
this License for any reason.


                                   ARTICLE V
                                  MISCELLANEOUS

     5.1 TAXES.  Customer shall be solely  responsible  for all state,  local or
federal taxes, however designated, levied or based on any fees payable hereunder
(excluding those taxes based on net income derived from BCS),  including but not
limited to state and local  privilege  and excise taxes based on gross  revenue,
and any sales  taxes or  amounts  in lieu  thereof,  paid or  payable  by BCS in
respect of the foregoing. Customer shall pay any such taxes to BCS no later than
thirty (30) days after Customer's  receipt of invoice from BCS.  Customer hereby
indemnifies  and  holds BCS  harmless  from and  against  any  losses  caused by
Customer's  failure to pay any such taxes,  including  any penalties or interest
thereon  incurred  with respect to such taxes.  BCS will inform  Customer of any
audit by any governmental authority regarding such taxes, will allow Customer to
control any challenge to, settlement of or payment of any amounts deemed payable
by such  government  authority  as a result of such audit or  inquiry,  and will
cooperate  with  all  reasonable  requests  by  Customer  for BCS to  assist  in
challenging,  settling and paying such amounts.  Customer's obligations pursuant
to this Section 5.1 shall survive any termination or expiration of this License.


                                       9


     5.2  EXCUSED  PERFORMANCE.  Except  for  Customer's  obligation  to pay BCS
hereunder, Customer and BCS shall be excused from performance, and shall have no
liability,  for any period and to the extent that  either of them is  prevented,
hindered or delayed from performing any services or other obligations under this
License,  in whole or in part,  as a result of acts,  omissions or events beyond
the reasonable  control of such party,  including by way of illustration and not
limitation, acts or omissions of Customer; failure or malfunction of computer or
telecommunications  hardware,  equipment  or  software,  beyond  the  reasonable
control of such party (other than the telecommunications  hardware, equipment or
software that is the subject of this License); breach or other nonperformance by
BCS' or Customer's vendors and suppliers; strikes or labor disputes; riots; war;
fire; acts of God or governmental regulations (excluding any problems due to the
Licensed  Software's  failure to be Year 2000  Compliant  as required  under the
License).

     5.3  EMPLOYEES.  Customer and BCS  acknowledge  that their success in their
respective industries is largely dependent on the performance of their personnel
and that, therefore, Customer and BCS expend substantial resources in connection
with employment and training.  Accordingly,  neither Customer nor BCS shall hire
or retain, either as an employee or independent contractor, any person who was a
Restricted Employee of the other party at any time during the twelve (12) months
preceding  such hiring or  retention,  without  obtaining  the  advance  written
consent of such other  party.  A  Restricted  Employee of Customer or BCS is any
employee  or third party  independent  contractor  of Customer or BCS,  except a
member of the  clerical  staff.  This  undertaking  by Customer and BCS shall be
deemed an essential element of this License and shall survive its termination.

     5.4 NO WAIVER.  No failure of either  party to exercise  any power or right
given either party hereunder or to insist upon strict compliance by either party
with its  obligations  hereunder,  and no custom or  practice  of the parties at
variance with the terms hereof shall constitute a waiver of either party's right
to demand exact compliance with the terms hereof.

     5.5  RIGHTS  CUMULATIVE.  All  rights,  powers,  and  privileges  conferred
hereunder  upon the parties  shall be  cumulative  and shall not restrict  those
given by law.

     5.6  SINGULAR  INCLUDES  PLURAL.  The  singular of any word in this License
includes the plural.

     5.7 NOTICES. Whenever under this License one party is required or permitted
to give notice to the other, such notice shall be deemed given when delivered in
hand or three (3)  business  days after the date mailed by United  States  mail,
certified mail, return receipt requested,  postage prepaid,  or one business day
after deposit with Federal Express where the notice has been designated for next
day priority delivery, and addressed as follows:



                                       10


In the case of BCS:

            Billing Concepts Systems, Inc.
            7411 John Smith Drive
            San Antonio, Texas 78229
            Attention:  Mike Hancock
            cc:  General Counsel
            Facsimile: (210) 949-4375

In the case of Customer:

            KMC Telecom Holdings, Inc.
            1545 Route 206, Suite 300
            Bedminster, New Jersey 07921
            Attention:  Paul DiMarco
            Facsimile:  (908) 719-8775

Either  party may change its  address  for  notification  purposes by giving the
other three (3) days prior  written  notice of the new address and the date upon
which it will become effective.

     5.8 DISPUTE RESOLUTION. This Section 5.8 governs any dispute, disagreement,
claim or  controversy  between  Customer and BCS arising from or related to this
License (a "Disputed  Matter").  All Disputed  Matters shall be submitted to the
following dispute resolution process:

     (a)  INTERNAL  ESCALATION.  First,  the  Disputed  Matter shall be referred
          jointly  to  senior  executives  of  each  of  the  parties.  If  such
          executives  do not agree upon a  resolution  within ten (10)  business
          days after referral of the matter to them, the complaining party shall
          proceed to the next stage of this dispute resolution procedure.

     (b)  MEDIATION. The complaining party shall, upon written notice and within
          ten (10) business days after the conclusion of the internal escalation
          procedure,  elect to have the Disputed  Matter referred to non-binding
          mediation before a single impartial mediator to be jointly agreed upon
          by the parties.  The mediation hearing shall be attended by executives
          of both parties  possessing  authority to resolve the Dispute  Matter,
          and shall be conducted no more than thirty (30)  business days after a
          party serves a written notice of an intention to mediate. Customer and
          BCS shall share equally all costs of such  mediation.  If the Disputed
          Matter cannot be resolved at mediation,  the  complaining  party shall
          proceed to the next stage of this dispute resolution procedure.

     (c)  ARBITRATION. In the event that a Disputed Matter has not been resolved
          through  mediation,  the  complaining  party shall submit the Disputed
          Matter to binding arbitration  pursuant to the Commercial  Arbitration
          Rules  of  the  American  Arbitration  Association  (the  "AAA").  The
          arbitration  panel  shall  have the  authority  to render any award or
          remedy  allowed by law. The  arbitration  panel shall consist of three
          neutral arbitrators selected from the AAA's Panel of Arbitrators,  and


                                       11


          the arbitration  hearing shall be conducted in Dallas,  Texas.  Within
          ten (15) days  after  receipt  of notice by a party of  submission  to
          arbitration,  each party  shall  designate  in writing one (1) neutral
          arbitrator  from  the  AAA's  Panel  of  Arbitrators,  and the two (2)
          arbitrators  named by the parties  shall  select the third  arbitrator
          from the AAA's Panel of Arbitrators.  If the two arbitrators  selected
          cannot agree upon a third  arbitrator,  the third  arbitrator  will be
          selected by the AAA in accordance with the AAA Rules. Each party shall
          be  entitled to conduct  not more than three (3)  depositions,  not to
          exceed  8  hours  each,  within  thirty  (30)  days  after  the  third
          arbitrator has been selected.  The parties shall diligently attempt to
          schedule  the  arbitration  hearing  for a time within one hundred and
          twenty (120) days after the demand for arbitration  hereunder has been
          issued.  Following the hearing,  the arbitrators shall issue a written
          decision  specifying the basis of their decision,  and the award made,
          if any. The cost of the arbitration proceeding shall be shared equally
          by the parties, but the prevailing party in any arbitration proceeding
          shall be entitled to recover its reasonable  and necessary  attorneys'
          fees  and  expenses  incurred  in  connection  with  the  arbitration.
          Provided  that  Customer  continues  to  timely  pay BCS for  services
          rendered  under this  License,  BCS shall  continue  to  provide  such
          services   during  the   pendency  of  any  Disputed   Matter   before
          arbitration. The arbitrators shall have no authority to award punitive
          or exemplary damages or to award damages in excess or in contravention
          of this License.

     (d)  INJUNCTIVE RELIEF PENDING ARBITRATION.  NOTWITHSTANDING THE FOREGOING,
          HOWEVER,  IT IS AGREED  THAT ANY BREACH OF THIS  LICENSE  BY  CUSTOMER
          MAKING ANY  UNAUTHORIZED  USE OF THE LICENSED  SOFTWARE OR ENGAGING IN
          ANY OTHER CONDUCT WHICH COULD IMPAIR BCS'  COPYRIGHTS OR  INTELLECTUAL
          PROPERTY  RIGHTS IN THE LICENSED  SOFTWARE  WILL CAUSE  IMMEDIATE  AND
          IRREPARABLE  HARM TO BCS. IN THE EVENT OF ANY SUCH BREACH BY CUSTOMER,
          BCS SHALL BE  ENTITLED  TO PURSUE  IMMEDIATE  AND  INTERIM  INJUNCTIVE
          RELIEF  FROM ANY COURT OF  COMPETENT  JURISDICTION  TO  RESTRAIN  SUCH
          UNAUTHORIZED USE OR CONDUCT, AND OBTAIN OTHER INJUNCTIVE RELIEF AS MAY
          BE NECESSARY  TO PROTECT BCS'  COPYRIGHTS  AND  INTELLECTUAL  PROPERTY
          RIGHTS.

     5.9  RELATIONSHIP  OF  PARTIES.  In  licensing  the  Licensed  Software  to
Customer,  BCS is acting only as an  independent  software  licensor.  Except as
expressly set forth in this  License,  BCS does not undertake by this License or
otherwise  to  perform  any  obligation  of  Customer,   whether  regulatory  or
contractual,  or  to  assume  any  responsibility  for  Customer's  business  or
operations.  This  License  shall not be deemed to create a  partnership,  joint
venture or fiduciary relationship between the parties.

     5.10 CONSEQUENTIAL  DAMAGES OF BCS. Customer shall not be liable to BCS for
any loss of  profits,  any  incidental,  special,  exemplary,  or  consequential
damages of any kind in connection with this License.

                                       12


     5.11 SEVERABILITY. In the event any provision of this License is held to be
unenforceable  or invalid by any court of competent  jurisdiction,  the validity
and  enforceability  of the  remaining  provisions  of this License shall not be
affected and, in lieu of such invalid or unenforceable provision, there shall be
added automatically as part of this License one or more provisions as similar in
terms as may be valid and enforceable under applicable law.

     5.12 ENTIRE  AGREEMENT.  This  License  and all  Exhibits  and  attachments
hereto,  together with the Hardware and Software Procurement Agreement,  Product
Support Agreement,  Outsourcing Agreement and the Consulting Services Agreement,
all dated as of the date  hereof,  between BCS and  Customer  (collectively  the
"Other  Agreements"),  constitutes the entire agreement between the parties with
respect  to  the   subject   matter   hereof  and   supersedes   all  prior  and
contemporaneous  representations,  understandings or agreements, whether oral or
written,  relating to the subject  matter hereof.  All prior or  contemporaneous
representations, understandings or agreements, whether oral or written, that are
not  expressly  set forth  within the four  corners of this License or the Other
Agreements are hereby deemed waived, superseded and abandoned.

     5.13  AMENDMENTS.  No  amendment  or  modification  of this License will be
binding on either of the  parties  to this  License  unless  such  Amendment  is
contained  in a written  document  which  expresses  an  intention to amend this
License and is executed by both the parties.

     5.14 COUNTERPARTS. This License may be executed in several counterparts all
of which  taken  together  shall  constitute  one single  agreement  between the
parties.

     5.15 HEADINGS.  The article and section  headings  included in this License
are  for  reference  and   convenience   only  and  shall  not  enter  into  the
interpretation of this License.

     5.16 GOVERNING LAW AND VENUE.  This License shall be governed and construed
in accordance with the laws of the State of Texas,  without regard to the choice
of law rules of Texas.  All suits  concerning any and all matters  related to or
arising  under or by virtue of this License  shall be commenced  exclusively  in
either the State Courts  located in Dallas,  Texas or the federal courts located
in Dallas, Texas, and venue of any such action shall rest exclusively in Dallas,
Texas.

     5.17  CURRENCY.  All monetary  amounts stated in this License are stated in
United States  Dollars,  and all amounts due hereunder shall be paid by Customer
in United States Dollars.

     5.18 TERMS  CONFIDENTIAL.  The terms and  conditions  of this  License  are
confidential  and shall be treated as such by Customer and BCS. Neither Customer
nor BCS will disclose the terms of this License to third parties,  including the
amount of fees to be paid hereunder, except as may be required for the filing of
reports and forms with  governmental  agencies  under  applicable  statutes  and
regulations.  Notwithstanding the foregoing,  however,  BCS may disclose that it
has  entered  into this  License  in a press  release  (previously  approved  by
Customer,   such  approval  not  to  be  unreasonably  withheld)  and  in  sales
presentations  to third  parties,  and BCS may  generally  describe the services
provided to Customer without disclosing the pricing terms contained herein.


                                       13


IN  WITNESS  WHEREOF,  the  parties  hereto,  each  acting  under due and proper
authority, have executed this License on the dates indicated below.

BILLING CONCEPTS SYSTEMS, INC.            KMC TELECOM HOLDINGS, INC


By:    /S/  MICHAEL A. HARRELSON          By:    /S/  MICHAEL STERNBERG         

      (Signature-Authorized Officer)         (Signature-Authorized Officer)


Name:   Michael A. Harrelson              Name:  Michael Sternberg 
Title:  President/COO                     Title:  President        
Date:   12/31/98                          Date:  December 31, 1998 
                                          


                                       14


                                    EXHIBIT A

                                   MBA SYSTEM
                                LICENSE SCHEDULE

Customer is licensing the BCS system known as the MBA Base System, Release
No. 3.0, which includes the following Standard Modules: Customer Acquisition,
Customer Care, Product and Rate Definition, Invoice Preparation, Accounts
Receivable and Payments Processing.

Customer is also licensing the following MBA Base Options:

Travel Card Processing
Switch Interface

Customer is also licensing the following MBA Item Rating Modules:

Local
Data
Private Line
Internet

Customer is also licensing the following Usage Rating Modules:

Usage
Carrier Access Billing

Customer is also licensing the following Non-MBA Software: Seagull (GUI), at the
license fees reflected in Exhibit B.

In  addition   to  the   above-listed   software,   BCS  grants  to  Customer  a
non-exclusive,  nontransferable  and  perpetual  license to use:  (i) any System
Releases or PTFs for the  above-listed  software  obtained by Customer  from BCS
pursuant  to a  product  support  or  other  agreement  entered  into by BCS and
Customer;   and  (ii)  any  modifications  made  by  BCS  for  Customer  to  the
above-listed  software.  Customer  shall  be  entitled  to use  such  additional
software items at no additional license fee.

Customer  acknowledges  that it will be  necessary  for  Customer  to enter into
separate  licensing  arrangements at Customer's expense with Vertex and Bellcore
to license related software  necessary to process  Customer's data using the MBA
System.




                                       15


                                    EXHIBIT B

                                THE LICENSE FEES

Customer  shall pay to BCS an initial  license  fee of  $1,749,166  which  shall
entitle Customer to use the licensed software components up to the maximum usage
levels indicated below:

MBA LICENSED SOFTWARE COMPONENT  MAXIMUM USAGE LEVEL              LICENSE FEE

MBA Base System                  125,000 Accounts                 $250,000
Travel Card Processing           125,000 Accounts                 $12,500
Switch Interface                 125,000 Accounts                 $25,000
Local Item Rating Module         125,000 Billed Items Per         $375,000
                                   Month                         
Data Item Rating Module          50,000 Billed Items Per Month    $50,000
Private Line Item Rating Module  50,000 Billed Items Per Month    $35,000
Internet Item Rating Module      25,000 Billed Items Per Month    $35,000
Usage Rating Module              50,000,000 Billed Records        $933,333
                                 Per Month]                      
CABS Usage Rating Module         2,500,000 Billed Records Per     $33,333
                                 Month]                          
================================================================================
GRAND TOTAL OF MBA LICENSE FEE                                    $1,749,166

NON-MBA LICENSED SOFTWARE        MAXIMUM USAGE LEVEL              LICENSE FEE
                                                    
Seagull GUII Software Copies     150 Seats                        $37,750
================================================================================
GRAND TOTAL OF NON-MBA LICENSE FEE                                $37,750


In the event that Customer's  usage of any of the licensed  software  components
exceeds the maximum usage levels  indicated  above for any three (3) consecutive
calendar monthly periods,  then Customer shall pay to BCS an additional  license
fee for the  licensed  software  component(s)  involved  at the prices set forth
below, and for the maximum usage levels set forth below:

A.    MBA BASE SYSTEM

      MAXIMUM USAGE LEVEL (TOTAL NUMBER OF ACCOUNTS)  LICENSE FEE

      250,000                                         $500,000
      350,000                                         $700,000
      500,000                                         $1,000,000
      650,000                                         $1,300,000
      800,000                                         $1,600,000
      1,000,000                                       $2,000,000


                                       16


B.    MBA BASE OPTIONS

      1.    TRAVEL CARD PROCESSING

      5% of the applicable license fee set forth in subsection A above.

      2.    SWITCH INTERFACE

      10% of the applicable license fee set forth in subsection A above.

C.   MBA ITEM RATING MODULES

      1.    LOCAL

      BILLED ITEMS PER MONTH                          LICENSE FEE

      250,000                                         $750,000
      350,000                                         $1,050,000
      500,000                                         $1,500,000
      650,000                                         $1,950,000
      800,000                                         $2,400,000
      1,000,000                                       $3,000,000

      2.    DATA

      BILLED ITEMS PER MONTH                          LICENSE FEE

      125,000                                         $125,000
      250,000                                         $250,000
      350,000                                         $350,000
      500,000                                         $500,000
      650,000                                         $650,000
      800,000                                         $800,000
      1,000,000                                       $1,000,000

      3.    PRIVATE LINE

BILLED ITEMS PER MONTH                                LICENSE FEE

      125,000                                         $93,750
      250,000                                         $187,500
      350,000                                         $262,500
      500,000                                         $375,000
      650,000                                         $487,500
      800,000                                         $600,000
      1,000,000                                       $750,000


                                       17


      4.    INTERNET

      BILLED ITEMS PER MONTH                          LICENSE FEE

      50,000                                          $50,000
      125,000                                         $125,000
      250,000                                         $250,000
      350,000                                         $350,000
      500,000                                         $500,000
      650,000                                         $650,000
      800,000                                         $800,000
      1,000,000                                       $1,000,000

D.   USAGE RATING MODULES

      1.    USAGE

      BILLED RECORDS PER MONTH                        LICENSE FEE

      75,000,000                                      $2,000,000

      2.    CABS

      BILLED RECORDS PER MONTH                        LICENSE FEE

      5,000,000                                       $66,667
      10,000,000                                      $133,333
      20,000,000                                      $266,667
      35,000,000                                      $466,667
      50,000,000                                      $666,667
      75,000,000                                      $1,000,000

E.   CALCULATION OF SEAGULL NON-MBA LICENSE FEES

     BCS will  procure for  Customer  the Seagull GUI software at a rate of $225
     per seat.

      INITIAL SEATS ORDERED                           LICENSE FEE
      150                                             $33,750

F.    CALCULATION OF ADDITIONAL LICENSE FEES.

      When Customer  exceeds the appreciable  maximum usage level for any of the
software components for three (3) consecutive calendar months, Customer shall be
required to pay the  difference  between its  currently  licensed  maximum usage


                                       18


level and the new maximum  usage level  license fee. For example,  if Customer's
total number of accounts  increases to 175,000,  then Customer shall be required
to pay an additional license fees calculated as follows:

MBA Base System Additional License Fee = $250,000 ($500,000 - $250,000)
Travel Card Processing Additional License Fee = $12,500 ([$500,000 -
$250,000] * .05)
Switch Interface Additional License Fee = $25,000 ([$500,000 - $250,000] * .
10)

Similarly,  if Billed Internet Items Per Month increases from 25,000 to 130,000,
then the additional license fee would be $220,000 ($250,000 - $35,000).

Payment by  Customer  of any  additional  license  fees due to BCS shall be made
within thirty (30) days after the end of the third consecutive  calendar monthly
period in which usage has  exceeded the capacity for which the software has been
licensed.  Thereafter,  further  increases  in  usage of the  licensed  software
components by Customer over any three (3) consecutive  calendar  monthly periods
shall require  Customer to pay further  additional  license fees as set forth in
Exhibit B.

Customer  shall in no event be  entitled  to receive  any refunds or credits for
license fees in the event that Customer's  maximum usage levels decrease for any
period of time.


                                       19