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                                      LEASE

     THIS LEASE is made and entered into by and between Henry G. Luken, III, a
Tennessee resident, herein called "Owner", and Covista Communications Company, a
New Jersey company, herein called "Tenant".

     For acknowledged consideration, Owner leases to Tenant and Tenant rents
from Owner the real property located at 2nd Floor of 721 Broad Street in the
City of Chattanooga, County of Hamilton, State of Tennessee, being the property
more fully described in Exhibit A, attached hereto, together with all
improvements and additions thereon, herein called the "premises"; and Owner and
Tenant agree as follows:

                                    SECTION 1
                         TERM AND OPTION TO EXTEND TERM

     1.1 The term of this lease shall be for five (5) years beginning on the 1st
day of October, 2002.

     1.2 Tenant shall have the option to extend the term of this lease for an
additional five (5) years, this option is to be exercised by giving written
notice to Owner at least ninety (90) days prior to the expiration of the then
current term under this lease. During the extended term, the provisions of this
lease shall remain the same except that the amount of rent shall be increased if
and to the extent provided by this lease.

     1.3 Owner shall not be liable for failure to give possession of the
premises to Tenant upon the effective date of this lease if the failure occurs
because the premises are not ready for occupancy, or are being held over by a
prior tenant or are otherwise in the wrongful possession of another party, or
are not available for any other reason. In such event the rent shall not begin
until possession is given to or made available to Tenant, and the term of this
lease shall not be extended by such delay in delivering possession. If the delay
in possession exceeds thirty (30) days, either Owner or Tenant, by written
notice to the other, may terminate this lease and neither party shall have nor
incur any liability or obligation to the other party as a result of such
termination.

                                    SECTION 2
                                      RENT

     2.1 During the lease Tenant shall pay and Owner shall accept a rental as
follows:

<TABLE>
<CAPTION>
           Rental Period                      Rent
------------------------------------   -----------------
<S>                                    <C>
October 1, 2002 - September 31, 2003   $ 8,334 per month
October 1, 2003 - September 31, 2004   $ 9,167 per month
October 1, 2004 - September 31, 2005   $10,000 per month
</TABLE>





<Page>



The rental for each month beginning on October 1, 2005, and the rental for any
extended term if the term of this lease is extended beyond the original term,
shall be Ten Thousand Dollars ($10,000) per month or, if greater, the amount
determined by multiplying the rental for each month of the prior year by a
fraction, the numerator of which is the Consumers Price Index United States -
All Items, for January of the fourth and fifth year or each year of the extended
term, and the denominator of which is such index figure on the same base, for
January of 2005, provided that such fraction shall never be less than one (1).

     2.2 In addition to these rental payments, Tenant shall pay when due, as
additional rent, all other amounts to be paid by Tenant under this lease.

     2.3 It is the intention of Owner and Tenant that the rent paid under this
lease shall be net to Owner and that each year during the term of the lease all
costs, expenses and obligations of every kind relating to the premises (except
as otherwise specifically provided in this lease) which may arise or become due
during the term of this lease shall be paid by Tenant, and that Owner shall be
indemnified by Tenant against such costs, expenses and obligations.

     2.4 All payments of rent shall be made by Tenant to Owner without notice or
demand, at such place within the United States as Owner may from time to time
designate in writing. For the present Owner designates Owner's address stated in
or pursuant to the Notices provisions of this lease as the place for making the
payments of rent. All rents shall be payable in legal tender of the United
States as the same is then constituted.

     2.5 A late fee will accrue at the rate of twelve percent (12%) per annum on
all delinquent rent and other amounts due from Tenant. Such late fee shall be
immediately due and payable as additional rent under this lease.

                                    SECTION 3
                                    UTILITIES

     Landlord shall pay for the following utilities: water, gas, electricity,
sewage disposal, and heat.

                                    SECTION 4
                                      TAXES

     4.1 Tenant shall pay all real property taxes, assessments and governmental
levies on the premises.

     4.2 Tenant shall pay any license tax or other tax on the business activity
of Tenant and on property belonging to Tenant and situated on the premises, and
any real property tax attributable to any additions or improvements added to the
premises by Tenant.


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                                    SECTION 5
                                TAX CERTIFICATION

     Owner hereby certifies that Owner is not a non-resident alien, or foreign
corporation, a foreign partnership, a foreign trust or a foreign estate (as
those terms are defined in the Internal Revenue Code and Income Tax
Regulations); that Owner's Social Security number or Federal Income Tax number
and home or office address are as shown in this Lease. Owner acknowledges that
this certification may be disclosed to the Internal Revenue Service pursuant to
federal law.

                                    SECTION 6
                      REPAIRS, MAINTENANCE AND IMPROVEMENTS

     6.1 Tenant shall at its own expense keep the premises clean, neat and free
of all trash or rubbish.

     6.2 Tenant shall, at Tenant's expense, maintain and keep in good repair the
interior of the premises including but not limited to the ceiling, light
fixtures, interior walls and floors, all doors, windows, glass, and plumbing,
all water and gas pipes, and sprinkler system, if any.

     6.3 Owner shall, at Owner's expense, make all necessary exterior structural
repairs including but not limited to the roof, gutters and downspouts, and the
outside walls of the premises, and the exterior of all improvements on the
premises.

     6.4 The parking lot paving, parking areas, sidewalks, lawns and landscaping
shall be maintained by Tenant.

     6.5 Owner shall, at its own expense, make all structural repairs and
restorations, whether or not interior or exterior, ordinary or extraordinary,
recurring or nonrecurring in nature, and shall keep the premises in good repair,
ordinary wear and tear, and damage by reason of natural causes or fire excepted.

     6.6 Tenant may make reasonable alterations, additions and improvements to
the premises, including the erection of signs, at Tenant's expense but only with
the prior consent in writing of Owner. All such work shall be in compliance with
all applicable federal, state and local laws and regulations, including those
pertaining to access to public accommodations, and Owner's consent to make such
alterations will not relieve Tenant of such responsibility. All alterations,
additions or improvements made by either of the parties, except movable office
furniture and movable business fixtures and equipment put in at the expense of
Tenant, shall inure to the benefit of Owner and shall belong to Owner absolutely
as soon as made or installed. Tenant may, if Tenant is not in default on any of
the terms and conditions of this lease, remove at the termination of the lease
any movable office furniture or movable business fixtures or equipment purchased
or provided by Tenant that may be moved without damage to the building, provided
that Owner is notified before the termination date that this right will be
exercised, as to described fixtures or equipment. If Tenant causes any damage to
the premises in removing Tenant's property, Tenant shall pay for all repairs.


                                       -3-





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     6.7 Upon termination of this lease Tenant shall return the premises to
Owner in the same condition as when received, ordinary wear and tear excepted.

                                    SECTION 7
                        LIABILITY INSURANCE AND INDEMNITY

     7.1 In addition to any insurance which Tenant deems necessary to protect
Tenant's interests, Tenant shall, at Tenant's expense, secure and maintain
during the term and any extended term of this lease, liability insurance with an
insurance company satisfactory to Owner, with Tenant and Owner as named
insureds, in amounts not less than $1,000,000 per person, $1,000,000 per
occurrence for all persons and $500,000 for property damage. Tenant may, in lieu
of delivering the original policies of insurance, deliver to Owner insurance
company certificates evidencing the coverage. The requirement of the liability
insurance notwithstanding, Owner shall not be liable for any injury or damage to
persons or property occurring in or about the premises, and Tenant shall save
Owner harmless from responsibility for any and all such injuries and for all
such damage arising from any cause whatsoever. Owner shall be under no liability
to Tenant arising from any discontinuance of heat or water, or both, caused by
accident, by breakage, by strike, or otherwise. Owner shall not be liable for
loss of or damage to the property of Tenant caused by rain, snow, water or steam
that may leak into or flow from any part of the premises as a result of any
defect in the roof or plumbing or any cause whatsoever, or for loss or damage
caused by the handling of electric wires or lights.

     7.2 If the Tenant shall fail, refuse or neglect to obtain such insurance or
to maintain the same, and furnish the Owner with proof of the same upon demand,
the Owner shall have the right, in addition to other remedies, to procure such
insurance and to add the cost thereof to any rental or other sums payable under
this lease, and the amount thereof shall be payable to the Owner on demand with
lawful interest thereon.

     7.3 Tenant shall cause any policy or certificate of insurance required by
this lease to be issued promptly upon any renewal or extension of such coverage
showing the Owner as insured.

                                    SECTION 8
                     CASUALTY INSURANCE AND CASUALTY DAMAGE

     8.1 Tenant shall secure and constantly maintain, at Tenant's expense,
insurance against loss or damage by fire and such other casualty risks and
hazards, including but not limited to lightning, flood and windstorm, as are
insurable under present and future standard forms of extended coverage insurance
policies, upon the buildings and other improvements erected on the premises.


                                       -4-





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Any such policy or policies of insurance shall name Owner as the insured, and
shall otherwise be in a form approved by Owner.

     8.2 Tenant shall furnish the original of such policy to Owner or insurance
company certificates evidencing the coverage.

     8.3 If the premises are so used that casualty insurance cannot be secured,
Tenant will become the insurer, and Owner may cancel this lease by giving
written notice to Tenant.

     8.4 If the premises are rendered totally or substantially untenantable by
fire or other casualty, this lease, at the option of Owner or Tenant exercised
in writing within thirty (30) days of the date of the fire or casualty, shall
terminate; otherwise Owner shall restore the premises as rapidly as sound
business judgment permits.

     8.5 If the premises are rendered totally or substantially untenantable, and
are to be restored, rent will abate during restoration and the term of this
Lease shall be extended for a period of time equal to the period of time of such
restoration. If the premises are so damaged that Tenant can continue to occupy
the same or part of same, the rent shall abate pro rata only and Owner shall
repair the damage as rapidly as sound business judgment permits.

     8.6 The Owner shall have the sole and exclusive right to the proceeds of
any insurance covering the premises whether provided by Owner or Tenant. If any
restoration or repair work is to be done, the proceeds of any insurance shall be
provided to Owner for that purpose. Any insurance proceeds in excess of the cost
of such restoration or repairs, or all of the insurance proceeds if the premises
are not to be restored or repaired pursuant to the provisions of this lease,
shall be the sole property of and paid to Owner, and Tenant shall have no
interest therein. In the event of a mortgage or encumbrance on the premises
which requires that the insurance proceeds be used to retire or pay such
mortgage or encumbrance, then Owner shall have no obligation to rebuild or
repair and this lease may be terminated upon notice to Tenant following any fire
or casualty.

     8.7 Tenant shall carry and maintain at its own expense such insurance as
Tenant deems necessary or advisable to protect its interests under this lease
with regard to Tenant's fixtures, equipment and merchandise located at the
premises.

                                    SECTION 9
                               WARRANTIES OF OWNER

     9.1 Owner warrants and covenants that Owner is lawfully able to demise the
premises and that Tenant, on paying the rental herein provided and performing
the other covenants and conditions herein contained, shall have quiet and
peaceful possession of the premises during the lease term. No provisions of this
lease are intended to warrant or imply that Owner has any greater right or
interest than stated in this paragraph.


                                       -5-





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     9.2 Except as otherwise specifically provided in this lease, Tenant is
acquainted with the entire premises and accepts the same in their present
condition. Tenant assumes responsibility for the safety of the premises, for the
suitability of the premises for Tenant's use, and for the premises' compliance
with the requirements of Title III of the American with Disabilities Act of
1991.

     9.3 Owner makes no other warranties express or implied.

     9.4 No representation is made as to the adequacy or availability of
parking.

                                   SECTION 10
                             SUBLEASE OR ASSIGNMENT

     Neither Tenant nor any court or officer thereof or receiver or trustee in
bankruptcy shall sublease, assign, or transfer the premises or any interest in
this lease without the consent in writing of Owner, which shall not be
unreasonably withheld. Landlord may withhold consent if the premises is not
currently a place of public accommodation and the subletting or assignment will
cause it to be used at such. In the event of a sublease or assignment, Tenant
shall always remain liable for any default of a subtenant or assignee. The
receipt by Owner of rents from any assignee, subtenant or occupant shall not be
deemed to be a waiver of these provisions.

                                   SECTION 11
                                 USE OF PREMISES

     The premises shall during the term of this lease be used only as a switch
station for office space, and no part of the premises or improvements thereon
shall be used in any manner whatsoever for a purpose in violation of the laws of
the United States or the state in which the premises are located or any other
applicable ordinance, regulation or law. Tenant shall comply with all laws,
ordinances, regulations or orders enacted or passed during the term of this
lease applicable to the premises.

                                   SECTION 12
                                  CONDEMNATION

     If at any time a substantial part or all of the premises be taken for any
public or quasi-public use under any statute or by right of eminent domain or by
private purchase in lieu thereof by a body vested with the power of eminent
domain, this lease shall continue until the date of the taking, at which time
this lease shall terminate and Tenant shall have no rights in any award or
purchase price paid by reason of the taking. In the event a condemnation or
purchase takes place and the premises continue to be tenantable for Tenant's
purposes, the rent shall be abated pro rata, Tenant shall have no rights in any
award or purchase price paid by reason of the taking, and the lease shall
continue otherwise in full force and effect. The termination of this lease or
the abatement of rent by reason of the condemnation or purchase shall be without
prejudice to the rights of either Owner or Tenant (to the extent Tenant has an
independent claim) to recover compensation and damage caused by the


                                       -6-





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condemnation or taking from the condemner or taker. Neither Owner nor Tenant
shall have any rights in any award made to the other by reason of such
condemnation or taking.

                                   SECTION 13
                            ENVIRONMENTAL COMPLIANCE

     13.1 Tenant, at Tenant's Expense, shall comply with all Environmental Laws
(as defined below) pertaining to Tenant's business use and occupancy of the
Premises and shall promptly advise Owner of any Notice, as defined herein.
Tenant hereby agrees to and does indemnify and hold Owner harmless from and
against any and all liability, obligations, losses, damages, penalties, claims,
clean-up costs, fines, civil penalties and actions, suits, including legal fees
imposed on, incurred by, or reserved against Owner arising out of the existence
or presence of any "Regulated Substance", as defined herein, on, under or from
the Premises from and after the commencement of the initial term of this lease
("Commencement Date") arising out of Tenant's occupancy and use of the Premises;
and any liability, claims, or damages in any way related to or arising out of
the removal, treatment, storage, disposal, disposition, mitigation, clean-up or
remedying of by Tenant of Regulated Substances on the Premises. Notwithstanding
anything herein to the contrary, Owner agrees that Tenant has no obligation to
and does not indemnify Owner for any claims or damages due to any Regulated
Substances existing or present on the Demised Premises prior to the Commencement
Date or arising out of the acts of third parties not under Tenant's control.

     13.2 For the purposes of this Section 14, the following terms shall have
the meanings set forth herein:

          (a) "Environmental Laws" means any applicable federal, state,
regional, county or local laws, statutes, rules, regulations or ordinances,
including, but not limited to, the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended by the Superfund Amendments
and Reauthorization Act of 1986, 42 U.S.C. Section 9601 et seq. ("CERCLA"), the
Resource Conservation and Recovery Act of 1976, as amended by the Hazardous and
Solid Waste Amendments of 1984, 42 U.S.C. Section 6901 et seq. ("RCRA"), the
Federal Water Pollution Control Act, as amended by the Clean Water Act of 1977,
33 U.S.C. Section 1251 et seq ("CWA"), the Toxic Substances Control Act of 1976,
15 U.S.C. Section 2601 et seq. ("TSCA"), the Emergency Planning and Community
Right-To-Know Act of 1986, as amended, 42 U.S.C. Section 11001 et seq. ("Sara
Title III"), the Clean Air Act of 1986, as amended, 42 U.S.C. Section 7401 et
seq. ("CAA"), the National Environmental Policy Act and Harbors Act of 1899, 33
U.S.C. Section 401 et seq. ("RHA"), the Occupational Safety and Health Act of
1970, 29 U.S.C. Section 651 et seq. ("OSHA"), and the Safe Drinking Water Act of
1974, as amended, 42 U.S.C. Section 300(f) et seq. ("SDWA"), and any and all
rules, regulations and guidance documents promulgated or published thereunder,
and any other federal, state, county or local statute, law, rule, regulation or
ordinance relating to public health, safety or the discharge, emission, or
disposal to air, water, land or groundwater, to the withdrawal or use of
groundwater, to the use, handling or disposal of polychlorinated biphenyls
(PCB's), asbestos or urea formaldehyde, to the treatment, storage, disposal or
management of regulated substances (including without limitation, petroleum, its
derivatives, by-products or other hydrocarbons), to exposure to toxic,
hazardous, or other controlled, prohibited or other regulated


                                       -7-





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substances, to the transportation, storage, disposal, management or release of
gaseous or liquid substances, and any regulation, order, injunction, judgment,
declaration, notice or demand issued thereunder.

          (b) "Regulated Substances" means any substances, materials, wastes or
pollutants that are from time to time defined by or pursuant to or are regulated
as such under any statute, law, ordinance, rule or regulation of any federal,
state, regional, county or local authority having jurisdiction over the Premises
or its use, including without limitation, petroleum, petroleum derivatives or
by-products, or other hydrocarbons or any material, substance, pollutant or
waste that is (a) defined as a hazardous substance under Section 311 of CWA, (b)
defined as a hazardous waste under Section 1004 of RCRA, (c) defined as a
hazardous substance under Section 101 of CERCLA, or (d) otherwise regulated in
its transportation, storage, disposal, management or release by any federal,
state, county or local statute, law, rule, regulation or ordinance.

          (c) "Release" means releasing, spilling, leaking, pumping, pouring,
emitting, emptying, discharging, injecting, escaping, burying, leaching,
migrating, disposing or dumping (in the appropriate tense for the context used).

          (d) "Notice" shall mean any summons, citation, directive, order,
claim, litigation, investigation, proceeding, judgment, letter or other
communication, written or oral, actual or threatened, from the Tennessee
Department of Environment and Conservation ("TDEC"), the United States
Environmental Protection Agency ("EPA") or other federal, state or local agency
or authority, or any other entity or any individual, concerning any intentional
or unintentional act or omission that has resulted or that may result in the
release of regulated substances into the waters (including groundwaters) or onto
the lands of the State of Tennessee or adjacent jurisdiction, or into the
"environment" as such term is defined in CERCLA from or on the Premises, and may
include, without limitation (i) the imposition of any lien on the Premises,
pursuant to any Environmental Laws (as defined above) (ii) any violation of
federal, state, regional, county or local environmental laws, statutes, rules,
regulations, ordinances, governmental actions, orders or permits, or (iii) any
knowledge, after due inquiry and investigation, of any facts that could give
rise to any of the above.

                                   SECTION 14
                       MECHANICS' AND MATERIALMEN'S LIENS

     Tenant shall not do or suffer anything to be done whereby the premises
shall be encumbered by a lien, and shall, whenever and as often as any lien is
filed against the premises purporting to be for labor or material furnished or
to be furnished to the Tenant, discharge the same of record within twenty (20)
days after the date of filing. Tenant shall indemnify Owner from all actions and
costs of suit by any person to enforce a lien, together with any costs and
attorney fees incurred by Owner. Tenant may contest the validity of any lien or
claim if Tenant shall have posted a bond with adequate surety to insure that
immediately upon final determination of validity of the lien or claim Owner
shall be paid for any judgment rendered, with all proper costs and charges, and
Tenant shall at such time have the lien released without cost to Owner. Notice
is hereby given that Owner shall not be liable for any labor or materials
furnished or to be furnished to the Tenant on credit, and that no


                                       -8-





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mechanics', materialmen's or other lien for any such labor or material shall
attach to or affect the reversionary or other estate or interest of Owner in and
to the real estate and improvements which are a part of the premises.

                                   SECTION 15
                                 ENTRY BY OWNER

     Tenant shall permit Owner, or Owner's agents or employees, at all
reasonable hours, to enter and examine the premises, or to show the premises to
persons wishing to rent or purchase the same, or to make proper repairs or
alterations, taking any space needed; and during the two (2) months preceding
the termination of any term of this lease, Tenant will permit customary "For
Sale" or "For Rent" notices, or both, to be exhibited on the premises.

                                   SECTION 16
                                     DEFAULT

     16.1 Should Tenant be in default in the payment of rent and remain in
default for a period of ten (10) days, such default shall, at Owner's option,
constitute a forfeiture of the lease.

     16.2 Should Tenant violate any other term, condition, or covenant of this
lease and not cease or otherwise cure the violation within thirty (30) days
after receiving written notice from Owner, or if Tenant should abandon or vacate
the premises prior to the expiration of the original or any extended term of
this lease, or if Tenant should be adjudicated a bankrupt or insolvent according
to law, or should make an assignment for the benefit of creditors, or if a
receiver, trustee or liquidator of Tenant's property shall be appointed and not
discharged within sixty (60) days, then the occurrence of such act or omission
shall, at Owner's option, constitute a forfeiture of the lease.

     16.3 If a forfeiture is declared by Owner for any reason, then in addition
to and not in substitution for any responsibilities or liabilities of Tenant, or
any options available to Owner, under this instrument or applicable law:

          (a) Tenant shall be liable for all future rentals, any rents in
arrears and all other amounts necessary to compensate Owner for Tenant's
breaches of covenant, all such amounts to become immediately due and payable;
and

          (b) Owner may, at Owner's option: (i) lease the premises to another
tenant for part or all of the remainder of the term, in which event there shall
be set off against the amounts otherwise owed by Tenant the amount of rents
actually received from the new tenant less the costs related to entering into
the new lease and preparing the premises for the use of the new tenant; or (ii)
refrain from leasing the premises to another tenant, in which event there shall
be set off against the amounts owed by Tenant any portion of the loss of net
rental income available to Owner as to which Tenant may establish, in a court of
competent jurisdiction or to the satisfaction of Owner, that Owner could have
realized by leasing the premises to another tenant known to Owner, or to another
tenant


                                       -9-





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with which Owner may have been able to contract if Owner had expended reasonable
efforts to locate such a tenant.

     16.4 If, upon any forfeiture, Owner shall elect to recover possession of
the premises, no demand shall be necessary before such recovery of possession;
and Owner may enter the premises, or any part, and take possession and expel
Tenant or other occupants and their effects, without being guilty of any
trespass.

     16.5 Should Owner or Tenant fail to pay taxes or make repairs or fail to
perform any other duty under this lease the other party may, after giving thirty
(30) days' notice in writing, perform such duty and the cost of performance
shall be offset against or added to the rental amount and in the latter case
shall become immediately due and owing.

     16.6 The failure of Owner to declare a breach or forfeiture of this lease
for the violation of any term, condition or covenant shall not be construed as a
waiver of the rights to declare a breach or forfeiture of this lease upon the
occurrence of any subsequent act or omission, the right to declare a breach or
forfeiture being a continuing one in Owner. Acceptance of rentals subsequent to
any forfeiture shall not be considered a confirmation or renewal of this lease.

     16.7 Should Tenant vacate the premises prior to the expiration of the
original or any extended term of this lease, no act or actions taken by the
Owner or its agents shall be deemed an acceptance of a surrender of the
premises. No agreement to accept the surrender of the premises shall be valid
unless the same be in writing and signed by the Owner.

                                   SECTION 17
                                  SUBORDINATION

     This lease and all rights of Tenant hereunder are and shall be subject and
subordinate to the lien or liens of any and all mortgages, deeds of trust, deeds
to secure debt or other instruments in the nature thereof ("Owner's mortgage"),
and to all modifications, renewals or extensions thereof, which may now or
hereafter effect or encumber Owner's title to the premises. Tenant shall, upon
demand, at any time or times, execute, acknowledge, and deliver to Owner or to a
holder of Owner's mortgage, without expense, any instruments that may be
necessary to make this lease subordinate to the lien of Owner's mortgage.


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                                   SECTION 18
                          OCCUPATION AFTER TERMINATION

     Should Tenant continue in possession, with or without the consent of Owner,
after expiration of the term or after a forfeiture incurred, Tenant shall
continue paying the amount of rent specified in this lease and shall continue to
be subject to all of the terms and conditions of this lease, except that Tenant
shall be the tenant at will of Owner, and in no event a tenant from year to year
or from month to month, and Tenant may be required to vacate the premises
without notice and may be removed by legal process as upon a forcible and
unlawful detainer.

                                   SECTION 19
                                 ATTORNEY'S FEE

     If it shall become necessary for Owner or Tenant to employ an attorney to
assert any right or enforce any obligation under this lease, after default, such
party, if he prevails, shall be entitled to recover, in addition to all other
costs and expenses, the reasonable costs and charges of such attorney.

                                   SECTION 20
                                     NOTICES

     All notices or communications which this instrument requires or permits to
be given shall be in writing and shall be mailed or delivered to the respective
addresses set forth below, or to such other address as may be designated in
writing by either party.

     To Owner as follows:

     Henry Luken
     900 Fairway Lane
     Soddy Daisy, TN 37379-4520

     To Tenant as follows:

     Covista Communications Company
     721 Broad Street, Suite 200
     Chattanooga, TN 37402

                                   SECTION 21
                                 ENTIRE CONTRACT

     This lease contains the entire contract between the parties relating to the
demise of the premises and may not be altered, amended or changed except by
instrument in writing signed by both parties hereto.

                                   SECTION 22


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                                BENEFIT OF LEASE

     This lease shall inure to the benefit of and shall be binding upon the
heirs, legatees, legal representatives, and successors and assigns of the
parties, subject to all the terms, conditions and contingencies set forth.

                                   SECTION 23
                                 LAW APPLICABLE

     This is a lease under the laws of the state in which the premises are
located, and the validity and applicability of its provisions shall be governed
by the laws of that state.

                                   SECTION 24
                          AMERICANS WITH DISABILITY ACT

     Tenant represents and covenants that it shall conduct its occupancy and use
of the Premises in accordance with the Americans with Disabilities Act ("ADA"),
or any other federal, state or local law or regulation pertaining to public
accommodation access (including, but not limited to, modifying its policies,
practices and procedures, and providing auxiliary aids and services to disabled
persons at Tenant's expense). Tenant agrees to indemnify and hold Owner harmless
from all liability, damages, penalties, costs and attorney fees arising from any
claims brought or made against Owner resulting from Tenant's use, operation or
occupancy of the premises brought pursuant to the ADA or any other federal,
state or local law or regulation pertaining to public accommodation access. If
the Tenant is allowed to make alterations and improvements to the Premises in
conjunction with the Tenant taking occupancy of the Premises, Tenant agrees that
all such work shall comply with the ADA. Furthermore, Tenant covenants and
agrees that any and all future alterations or improvements made by Tenant to the
Premises shall comply with the ADA. Any improvements in the premises necessary
for Tenant's reasonable accommodation of its employees will be made at Tenant's
expense.

                                   SECTION 25
                              ESTOPPEL CERTIFICATE

     At any time and from time to time, Tenant, on or before the date specified
in a request theretofore made by Owner, shall execute, acknowledge and deliver
to Owner a certificate prepared by Owner at Owner's expense, evidencing whether
or not (a) this lease is in full force and effect, (b) this lease has been
amended in any way, (c) there are any existing defaults on the part of Owner
hereunder to the knowledge of Tenant and specifying the nature of such default,
if any, and (d) the date to which rent, and other amounts due hereunder, if any,
have been paid. Each certificate delivered pursuant to this Section 27 may be
relied on by any prospective purchaser or transferee of Owner's interest
hereunder or of any part of Owner's property or by any holder or prospective
holder of Owner's mortgage, or a mortgage or prospective mortgage of any part of
Owner's other property.

                                   SECTION 26


                                      -12-





<Page>



                            TERMINOLOGY AND CAPTIONS

     The terms "Owner" and "Tenant" as used in this lease shall be construed to
apply to the parties in the appropriate gender and number; and the term "Owner"
shall in no way indicate that a tenancy greater than that described in this
lease is either demised or warranted. The captions in this lease are inserted
only as a matter of convenience and for reference and in no way define, limit,
amplify or describe the scope of this lease or the intent of any provision
thereof.

     IN WITNESS WHEREOF, the Owner and Tenant have executed duplicate copies of
this lease this ______ day of ______________, 2002.

Copy No. ___


                                        -----------------------------------
                                        (Henry G. Luken, III)

                                                                           OWNER


                                        COVISTA COMMUNICATIONS COMPANY


                                        By:
                                            -------------------------------
                                                      President

                                                                          TENANT


                                      -13-





<Page>



STATE OF TENNESSEE      )
                        )
COUNTY OF HAMILTON      )

     Before me, a Notary Public, duly appointed, commissioned and qualified in
and for the State and County aforesaid, personally appeared Henry G. Luken, III,
the within named bargainor, with whom I am personally acquainted, and who
signed, sealed and delivered the foregoing instrument in my presence, and who,
upon oath, acknowledged that he executed the foregoing instrument for the
purposes therein contained as his free act and deed.

     IN WITNESS WHEREOF, I have hereunto set my hand and affixed my seal at my
office in said State and County, on this the _______ day of
_____________________, 2001.


                                        -----------------------------------
                                                   Notary Public

                                        My commission expires:_____________

STATE OF TENNESSEE      )
                        )
COUNTY OF HAMILTON      )

     Before me, a Notary Public, duly appointed, commissioned and qualified in
and for the State and County aforesaid, personally appeared
________________________, with whom I am personally acquainted, and who, upon
oath, acknowledged himself to be the President of Covista Communications
Company, the within named bargainor, a corporation, and that he, as such officer
of said corporation, being authorized so to do, executed the foregoing
instrument for the purposes therein contained, by signing the name of the
corporation by himself as President.

     IN WITNESS WHEREOF, I have hereunto set my hand and affixed my seal at my
office in said State and County, on this the _______ day of
_____________________, 2001.


                                        -----------------------------------
                                                   Notary Public

                                        My commission expires:_____________


                                      -14-