Document:

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                                                                     Exhibit 4.7

                                                               EXECUTION VERSION

                                 ENGLISH VERSION

               SECOND AMENDED AND RESTATED MASTER LEASE AGREEMENT
                              (FOR PURCHASED SITES)

      This Second Amended and Restated Master Lease Agreement (this "MASTER
LEASE" or "AGREEMENT") is entered into this 19th day of December 2003, among ,
with respect to those Sites purchased under the 2001 Purchase Agreement (as
defined below), MATC CELULAR, S. DE R.L. DE C.V. ("MATC CELULAR"), GRUPO
IUSACELL CELULAR, S.A. DE C.V. (f/k/a Grupo Iusacell, S.A. de C.V.) ("GRUPO
IUSACELL CELULAR") and IUSACELL ARRENDADORA, S.A. DE C.V. ("ARRENDADORA") and
with respect to those Sites purchased under the 2003 Purchase Agreement (as
defined below), MATC DIGITAL, S. DE R.L. DE C.V. ("MATC DIGITAL"), GRUPO
IUSACELL, S.A. DE C.V. (f/k/a Nuevo Grupo Iusacell, S.A. de C.V) ("GRUPO
IUSACELL") and ARRENDADORA (Arrendadora is referred to herein as "LESSEE" with
respect to Sites purchased under both the 2001 Purchase Agreement and the 2003
Purchase Agreement).

      Capitalized terms not otherwise defined herein shall have the respective
meanings set forth in Exhibit A attached to this Agreement and incorporated
herein by this reference.

                                    RECITALS

      I.    RECITALS OF GRUPO IUSACELL AND LESSEE.

      Grupo Iusacell recites that:

      a) It is a corporation duly incorporated and validly existing under the
laws of Mexico, with the power and authority to enter into this Master Lease and
to comply with its covenants and obligations as set forth hereunder, as
evidenced by Public Deed No. 33,275 granted on August 6, 1998, before Public
Notary No. 195 of the Federal District, Lic. Ana Patricia Bandala Tolentino,
which first copy is duly registered at the Public Registry of Commerce of the
Federal District, Mexico, under Commercial No. 242,349, on November 3, 1998.

      b) Its representatives are duly authorized and have the required legal
capacity to enter into this Master Lease on its behalf, and that their authority
has not been modified, restricted, revoked or otherwise amended since the date
on which it was granted, as evidenced by Public Deed No. 9,990 granted on July
28, 2003, before Public Notary No. 212 of the Federal District,

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Lic. Francisco Hugues Velez, which first copy is in the process of being
recorded at the Public Registry of Commerce of the Federal District, Mexico.

      c) The terms and conditions of this Master Lease do not contravene any of
its obligations under any agreements, permits, concessions and/or authorizations
to which it is a party and therefore does not constitute a breach of any of such
agreements, permits, concessions and/or authorizations.

      d) Grupo Iusacell has agreed to remain jointly and severally liable for
the obligations of Lessee under this Master Lease.

      Arrendadora recites that:

      a) It is a corporation duly incorporated and validly existing under the
laws of Mexico, with the power and authority to enter into this Master Lease and
to comply with its covenants and obligations as set forth hereunder, as
evidenced by Public Deed No. 1,557 granted on July 27, 2000, before Public
Notary No. 212 of the Federal District, Lic. Francisco I. Hugues Velez, which
first copy is duly registered at the Public Registry of Commerce of the Federal
District, Mexico, under Commercial No. 266651, on August 30, 2000.

      b) Its representatives are duly authorized and have the required legal
capacity to enter into this Master Lease on its behalf, and that their authority
has not been modified, restricted, revoked or otherwise amended since the date
on which it was granted, as evidenced by Public Deed No. 10,080 granted on
August 7, 2003, before Public Notary No. 212 of the Federal District, Lic.
Francisco I. Hugues Velez, which first copy is in the process of being recorded
at the Public Registry of Commerce of the Federal District, Mexico.

      c) The terms and conditions of this Master Lease do not contravene any of
its obligations under any agreements, permits, concessions and/or authorizations
to which it is a party and therefore does not constitute a breach of any of such
agreements, permits, concessions and/or authorizations.

      II. RECITALS OF MATC CELULAR. MATC Celular recites that:

      a) It is a corporation duly incorporated and validly existing under the
laws of Mexico, with the power and authority to enter into this Master Lease and
to comply with its covenants and obligations as set forth hereunder, as
evidenced by Public Deed No. 43,972 granted on October 5, 1999, before Public
Notary No. 1 of the Federal District, Roberto Nunez y Bandera, which first copy
is duly registered at the Public Registry of Commerce of Mexico City, Mexico,
under commercial number 253584, on October 27, 1999.

      b) Its representative is duly authorized and has full legal capacity to
execute this Master Lease on its behalf, and that his authority has not been
modified, restricted, revoked or otherwise amended since the date on which it
was granted, as evidenced by Public Deed No. 50,460 granted on October 20, 2003,
before Public Notary No. 1 of the Federal District, Roberto Nunez y Bandera,
which first copy is in the process of being recorded at the Public Registry of
Commerce of Mexico City, Mexico.

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      c) The terms and conditions of this Master Lease do not contravene any of
its obligations under any agreements, permits, concessions and/or authorizations
to which it is a party and therefore does not constitute a breach of any of such
agreements, permits, concessions and/or authorizations.

      III. RECITALS OF MATC DIGITAL. MATC Digital recites that:

      a) It is a corporation duly incorporated and validly existing under the
laws of Mexico, with the power and authority to enter into this Master Lease and
to comply with its covenants and obligations as set forth hereunder, as
evidenced by Public Deed No. 43,973 granted on October 5, 1999, before Public
Notary No. 1 of the Federal District, Roberto Nunez y Bandera, which first copy
is duly registered at the Public Registry of Commerce of Mexico City, Mexico,
under commercial number 253,585, on October 27, 1999.

      b) Its representatives is duly authorized and has full legal capacity to
execute this Master Lease on its behalf, and that his authority has not been
modified, restricted, revoked or otherwise amended since the date on which it
was granted, as evidenced by Public Deed No. 50,461 granted on October 20, 2003,
before Public Notary No. 1 of the Federal District, Roberto Nunez y Bandera,
which first copy is in the process of being recorded at the Public Registry of
Commerce of Mexico City, Mexico.

      c) The terms and conditions of this Master Lease do not contravene any of
its obligations under any agreements, permits, concessions and/or authorizations
to which it is a party and therefore does not constitute a breach of any of such
agreements, permits, concessions and/or authorizations.

      IV. RECITALS OF THE PARTIES. The parties recite that:

      a) MATC Celular, Grupo Iusacell and Lessee have previously entered into a
Master Lease Agreement, dated as of February 23, 2001 (the "ORIGINAL MASTER
LEASE AGREEMENT"), relating to the lease of space by Lessee at certain Sites
described herein, which Original Master Lease Agreement was amended and restated
as of May 16, 2002 (the "AMENDED AND RESTATED MASTER LEASE AGREEMENT").

      b) MATC Celular and certain Affiliates of Lessee have entered into that
certain Purchase and Sale Agreement dated as of February 23, 2001 (the "2001
PURCHASE AGREEMENT") and MATC Digital and certain Affiliates of Lessee have
entered into that certain Purchase and Sale Agreement dated as of the date
hereof (the "2003 PURCHASE AGREEMENT"; and collectively with the 2001 Purchase
Agreement, the "PURCHASE AGREEMENTS"), pursuant to which Lessee agreed to sell,
convey, assign, transfer and deliver to MATC, and MATC agreed to purchase and
acquire from Lessee, all of the right, title and interest of Lessee in and to
the Sites described therein, and the execution and delivery of this Master Lease
is a condition to MATC Digital's obligation under the 2003 Purchase Agreement to
purchase the Sites.

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      c) Lessee wishes to lease from MATC space for operating its communications
equipment: (i) with respect to all Sites purchased pursuant to the 2001 Purchase
Agreement (the "2001 PURCHASED SITES"), non-exclusive use of space on the
applicable tower within a twenty (20) foot expanse comprised of the ten (10)
feet above and the ten (10) feet below the height of the center of radiation of
Lessee's Improvements and Equipment located on the applicable tower structure
(unless such space is otherwise defined in the applicable Site Lease) and
non-exclusive use of certain rights of way granted under Section 1(f) of this
Agreement and (ii) with respect to all Sites purchased pursuant to the 2003
Purchase Agreement (the "2003 PURCHASED SITES"; and together with the 2001
Purchased Sites, the "SITES"), non-exclusive use of space on the applicable
tower within a ten (10) foot contiguous expanse comprised of the five (5) feet
above and five (5) feet below the height of the center of radiation of Lessee's
Improvements and Equipment located on the applicable tower structure and
non-exclusive use of certain rights of way granted under Section 1(f) of this
Agreement (the spaces described in subsections (i) and (ii), as applicable, are
referred to herein as the "PREMISES"), all at locations more particularly
described in a supplement to be executed in the form attached to this Master
Lease as Exhibit B, which form may be mutually amended by the parties hereto
from time to time (the "SITE LEASE"). Each of the Site Leases shall be governed
by the terms of this Master Lease and shall become a part of this Master Lease
as if fully set forth herein.

      d) The parties desire to amend the Amended and Restated Master Lease
Agreement as provided herein.

      NOW THEREFORE, based on the above, the parties agree as follows:

      1. LEASE OF PREMISES.

      (a) MATC does lease or own, and operates the Sites. Lessee shall lease
from MATC the Premises within each of the Sites, in consideration for which
Lessee shall pay rent as specified in Section 5 of this Agreement, and the
applicable Site Lease, under the terms and conditions of this Master Lease. Upon
execution and delivery of a Site Lease with respect to a particular Premises,
each Premises shall become subject to this Master Lease and the corresponding
Site Lease.

      (b) MATC Celular and Lessee executed a Site Lease with respect to each
2001 Purchased Site at the time such Site was purchased, all of which are set
forth in Schedule 1 attached hereto. There is no outstanding obligation to
purchase additional sites under the 2001 Purchase Agreement.

      (c) With respect to the 2003 Purchased Sites, at each Closing MATC Digital
and the applicable Lessee shall execute a Site Lease with respect to those Sites
being conveyed at the Closing. At each Closing, the list of Sites in Schedule 1
shall be amended to include the Sites transferred in connection with such
Closing and such amended list shall supercede any previous list of Sites in
Schedule 1. If MATC Digital or its Affiliate elect to exercise its right of
substitution pursuant to Section 2.5(d) of the 2003 Purchase Agreement, then the
Site Lease associated with the Put Tower (as defined in the 2003 Purchase
Agreement) shall be terminated and MATC Digital and the applicable Lessee shall
execute a new Site Lease with respect to the

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Exchange Tower (as defined in the 2003 Purchase Agreement), and in each case the
list of Sites in Schedule 1 shall be amended to remove the Put Tower and include
the Exchange Tower and such amended list shall supercede any previous list of
Sites in Schedule 1.

      (d) The parties agree that either party may request the registration of
any Site Lease at the Public Registry of Property corresponding to the
jurisdiction where any Site is located, as specified in the corresponding Site
Lease, and all costs and expenses associated with such registration shall be
borne solely by the requesting party.

      (e) As of the Commencement Date, MATC will grant the Lessee the use of the
Premises as provided in the applicable Site Lease, which Premises shall be ready
to be used by Lessee, under terms of Article 2412 of the Federal Civil Code and
the corresponding provisions of the Civil Codes of the States of Mexico, and
shall comply with all of its obligations thereunder or under the applicable
provisions of the Civil Codes of the jurisdiction in which any Premises are
located.

      (f) MATC shall lease to Lessee and Lessee shall lease from MATC the
Premises identified in each Site Lease, as of the Commencement Date and under
terms of this Master Lease. MATC grants Lessee the right to install and maintain
Lessee's Improvements and Equipment on the Premises and rights to install and
maintain utility wires, cables, conduits and pipes on the Site including over,
under or along a right of way extending from a public right of way to the Site,
and to utilize a right of way for access to the Site as described in Section
7(f) hereof and in the applicable Site Lease.

      (g) If the Premises are to be located on a Tower that is located on
property leased by MATC under any agreement with a third party owner of the
property (the "PRIME LEASE"), all terms, covenants and conditions contained in
this Master Lease (other than Section 13(c)(i) hereof) shall be specifically
subject and subordinate to the terms and conditions of any applicable Prime
Lease. In the event that any of the provisions of the Prime Lease supercede or
contradict the terms of this Master Lease (other than Sections 3, 5, 6, 9, and
13 hereof), such terms of this Master Lease shall be deemed deleted and
superceded to the extent of the contradiction as applicable to the space used by
Lessee. MATC covenants and agrees that it will not agree, without the prior
consent of Lessee (which consent shall not be unreasonably withheld), to any
modification of the terms of a Prime Lease prior to the termination or
expiration of such Prime Lease if such modification would contradict any
material term of this Master Lease and reasonably could be expected to have a
material adverse effect on Lessee. In the event the Prime Lease expires or is
terminated prior to the expiration of the Initial Term or any Renewal Term (as
such terms are defined in subsection (b) of Section 4), the corresponding Site
Lease shall terminate as between MATC and Lessee on the effective date of
termination of the Prime Lease, and MATC shall have no liability to Lessee
therefor. MATC shall give Lessee written notice of any such termination promptly
following its receipt of notice from the lessor under the Prime Lease. A copy of
the applicable Prime Lease will be provided to Lessee upon request, redacted as
deemed reasonably appropriate by MATC.

      (h) The parties hereto agree that the terms and conditions herein shall be
and are binding upon and exclusive to each party hereto with respect to any
lease of space by Lessee entered into

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during the Term of this Agreement with respect to any Site. The parties
acknowledge that each Site Lease shall be signed by MATC and Lessee. Lessee
warrants and represents that it has the authority to execute and deliver this
Agreement.

      2. USE OF THE PREMISES.

      Subject to Section 3, the Premises may be used by Lessee only to install,
maintain, repair, replace, remove and operate Lessee's Improvements and
Equipment on or in the Premises for the purposes of a telecommunications
facility and uses incidental thereto in connection with the provision of
wireless telecommunications services including, without limitation, cellular,
PCS, wireless local loop, paging, and fiber optic and microwave transmission
services.

      3. CONSTRUCTION AND ALTERATIONS.

      (a) Lessee shall be solely responsible for all costs and expenses
associated with the purchase, installation, repair, maintenance and alteration
of Lessee's Improvements and Equipment.

      (b) Except as otherwise provided for herein, Lessee agrees that it will
not make any alterations or additions to Lessee's Improvements and Equipment at
a Site until Lessee has submitted its construction and installation plans to
MATC in writing with respect to the installation of such Lessee's Improvements
and Equipment at such Site, and such plans have been approved in writing by
MATC. MATC's approval of Lessee's construction and installation plans shall not
be unreasonably withheld, conditioned, or delayed so long as such alterations or
additions (i) together with the remaining Lessee's Improvements and Equipment,
does not exceed the structural (e.g., wind load, weight, etc.) capacity required
on the Tower for the Maximum Equipment (as defined in Section 7(a)), (ii) does
not require any additional ground space, (iii) is proposed to be located on the
same height on the Tower structure as the existing Lessee's Improvements and
Equipment, (iv) the existing Tower structure can accommodate such additional or
altered installation without requiring MATC to make aggregate capital
expenditures (including all capital expenditures made in connection with any
prior structural modification of such Tower following the date of this
Agreement) with respect to such Tower in excess of US$70,000 and (v) do not
extend beyond the Premises except as provided in Section 7(g). Lessee shall not
alter any plans so approved without following the same procedures. Lessee shall
be responsible for ensuring that all external and internal wiring and cabling
installed by Lessee in the Premises is properly grounded to the grounding ring;
provided, however, that MATC shall be responsible for providing a common
grounding ring. Lessee shall obtain MATC's prior written approval of such
grounding plans, which approval shall not be unreasonably withheld, conditioned
or delayed. An amendment to the applicable Site Lease shall be prepared to
reflect each additional modification to Lessee's Improvements and Equipment from
time to time to which MATC has given its written consent. MATC may, in its
reasonable judgment, perform or cause to be performed a structural analysis to
determine the availability of capacity at the Site for the installation or
modification of any additional equipment by Lessee at the premises. Nothing
herein shall prevent Lessee from performing such analysis for its own account;
provided, however, that Lessee shall provide a complete copy of any structural
analysis that it performs to MATC at no cost to MATC promptly upon completion of
such analysis. If MATC performs

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such an analysis or causes one to be performed, Lessee agrees promptly to
reimburse MATC for all reasonable and documented costs and expenses incurred by
MATC or its vendor in the performance of such structural analysis within thirty
(30) days following receipt of an invoice from MATC. All approved work at the
Site shall be performed by qualified contractors, subject to the reasonable
approval of MATC. MATC and Lessee shall mutually agree, in writing, upon a list
of pre-approved contractors and subcontractors, and Lessee may retain any such
pre-approved contractor or subcontractor to perform services at the Site unless
MATC has previously informed Lessee in writing of MATC's reasonable desire to
remove such contractor or subcontractor from the approved list.

      4. TERM OF SITE LEASES AND MASTER LEASE; EXTENSION PERIODS.

      (a) The term of this Agreement shall commence on the date first written
above (the "EFFECTIVE DATE") and, unless earlier terminated in accordance with
Section 10, the terms and conditions of this Agreement shall remain in effect
with respect to each individual fully executed Site Lease for so long thereafter
as such Site Lease remains in effect pursuant to Section 4(b).

      (b) Unless the Site Lease specifies otherwise, the initial term of each
Site Lease shall commence on the Commencement Date for such Site Lease and shall
continue for ten (10) years (the "INITIAL TERM"); provided that the Initial Term
for any Exchange Tower (as defined in the 2003 Purchase Agreement) shall be
deemed for all purposes to be the same as the Initial Term for the Site for
which it is being exchanged; and provided further that effective January 1, 2004
the Initial Term for each of the Site Leases listed on Annex 2 shall continue
until January 1, 2015. The term of each Site Lease may be extended as follows:
(i) the term shall be extended automatically beyond its Initial Term for five
(5) years (the "FIRST RENEWAL TERM") unless Lessee notifies MATC that it does
not wish to extend the term and such notice is given at least 90 days before the
First Renewal Term is scheduled to begin, and (ii) the term shall be further
extended beyond the First Renewal Term for five (5) years (the "SECOND RENEWAL
TERM"; each of the First and Second Renewal Terms are sometimes referred to
herein as a "RENEWAL TERM") unless Lessee notifies MATC that it does not wish to
extend the term and such notice is given at least 90 days before the Second
Renewal Term is scheduled to begin. The lease term of any Site Lease shall be
the period commencing on the first day of the Initial Term and ending on the
last day of the last applicable Renewal Term, if so renewed, subject to the
provisions of Section 1(g) herein.

      5. RENT; REIMBURSABLE COSTS.

      (a) The rent payable to MATC by Lessee for the Premises under each Site
Lease shall be equal to the Base Rent (as defined in subparagraph (b) below) and
the Additional Rent (if any, as defined in subparagraph (c) below). The Base
Rent and Additional Rent payments shall be effected by deposit of immediately
available funds to MATC at an address to be identified to Lessee, in writing,
prior to the first Commencement Date of a Site Lease hereunder, as such address
may be changed from time to time upon written notice by MATC to Lessee.

      (b) The base rent (the "BASE RENT") for each Site under this Master Lease
shall be equal to the following, as applicable (plus applicable value added tax,
if any):

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            (i) For each 2001 Purchased Site, Two Thousand One Hundred
      Fifty-Three Dollars and 63/100 U.S.Cy. (US$2,153.63) per month, as
      adjusted below.

            (ii) For each Initial Site under the 2003 Purchase Agreement, Two
      Thousand Dollars and 00/100 U.S.Cy. (US$2,000.00) per month, as adjusted
      below.

            (iii) For each Additional Site under the 2003 Purchase Agreement,
      One Thousand Seven Hundred Fifty Dollars and 00/100 U.S.Cy. (US$1,750.00)
      per month, as adjusted below.

The Parties hereto acknowledge and agree that the Base Rent payable hereunder is
premised upon the installation of the Lessee's Improvements and Equipment as
specifically described in the applicable Site Lease but in no event to exceed
the Base Loading or extend beyond the Premises, except as provided for in
Section 7(g); provided, that in no event will Base Rent be reduced if Lessee has
not utilized the entire Premises or if Lessee has utilized less than the Base
Loading or if Lessee removes any equipment. For all Site Leases executed
pursuant to the 2001 Purchase Agreement (other than those listed on Annex 2
attached hereto), on July 1st of each year (commencing on July 1, 2004) the
applicable Base Rent and Additional Rent payable pursuant to Section 7(c) shall
be increased by three percent (3%) over the Base Rent and the Additional Rent,
respectively, for the prior year (i.e., the period beginning on July 1st and
ending on June 30th). For all Site Leases for MATC Sites executed pursuant to
the 2003 Purchase Agreement and for each Site Lease listed on Annex 2 attached
hereto, on July 1st of each year (commencing on July 1, 2004) the applicable
Base Rent and Additional Rent payable pursuant to Sections 7(c) shall be
increased by one and one half percent (1.5%) over the Base Rent and the
Additional Rent, respectively, for the prior year (i.e., the period beginning on
July 1st and ending on June 30th). The initial Base Rent payable under any Site
Lease entered into after July 1, 2004 shall be increased as described in the
previous sentence to account for the one and one half percent (1.5%) increase
each year from July 1, 2003 to the July 1st preceding the date of such Site
Lease.

      (c) In addition to the Base Rent payable under this Section 5, Lessee also
shall pay to MATC a monthly amount equal to its per capita portion (based on the
number of tenants who lease space on the applicable Tower for a rent equal to or
in excess of seventy-five percent (75%) of the Base Rent then-payable by Lessee
at the applicable Site ("PER CAPITA SHARE")) of MATC's ground rent (if any) and
real property taxes (if any) payable with respect to the applicable Site
(together with the additional rent described in Section 7(c) herein, "ADDITIONAL
RENT"); provided that in the event that the rental income (excluding service and
installation fees and any pass-through expenses, including, without limitation,
ground rent, taxes, utilities, etc.) that MATC is due to collect from Other
Tenants at any particular Site exceeds Five Thousand Eight Hundred Eighty Seven
United States Dollars ($5,887.00) (which amount shall be increased by a
percentage equal to the applicable increases in the Base Rent for such Site as
provided in Section 5(b)), Lessee shall be relieved of any obligation to pay its
Per Capita Share of the ground rent and real property taxes at such Site during
that calendar month; provided, however, if any uncollected rental income is
delinquent by ninety (90) days or more, MATC may retroactively recalculate and
prospectively calculate Lessee's entitlement to an abatement of Lessee's Per
Capita Share hereunder with respect to the affected Site(s) during any such
period of delinquency by Other Tenants by excluding such uncollected rents from
the amounts MATC is due to collect

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from Other Tenants. To the extent that MATC is required by the ground lease to
pay the ground rent in United States dollars, Lessee shall be required to pay
such portion of the Additional Rent in United States dollars. Payment of the
Additional Rent set forth in this Section 5(c) shall commence on the
Commencement Date of the applicable Site Lease. MATC will notify Lessee each
time any Other Tenant (as defined in Section 6(a)) installs its equipment on an
applicable Site.

      (d) All Base Rent and Additional Rent due hereunder shall be paid by
Lessee to MATC monthly, in advance. The first monthly payment shall be due
twenty (20) Business Days following the Commencement Date of the applicable Site
Lease and on the fifth day of each calendar month thereafter. The Additional
Rent for any fractional month or year (as applicable) at the beginning or at the
end of the Term shall be prorated.

      (e) In the event of any late payment of the Base Rent and/or Additional
Rent due under any Site Lease, without prejudice to any other rights or remedies
available to MATC under this Master Lease or any applicable laws, (i) Lessee
shall pay interest on any unpaid portion of such Base Rent and Additional Rent,
as of the date payment was due and until payment in full, at a rate per annum of
LIBOR (as determined by Citibank N.A. in New York) plus 200 basis points,
calculated on the basis of a year of three hundred and sixty (360) days and the
number of actual days elapsed, (ii) in addition, in the event that any payment
due under Site Lease remains outstanding for ninety (90) days or more following
each respective due date thereunder, Lessee shall pay, as liquidated damages
(pena convencional), an amount equivalent to one (1) payment of one-twelfth
(1/12) of the then current per annum Base Rent due for the applicable Site Lease
on the ninety-first (91st) day and at the end of each subsequent thirty (30)
days thereafter and (iii) in addition, if Lessee is in default on the payment of
Base Rent and/or Additional Rent for three (3) months or more with respect to
five percent (5%) or more of the Site Leases under this Agreement, then in
addition to any other remedies to which MATC may be entitled under this Section
5(e) and Section 10 hereof, at MATC's request Lessee shall immediately prepay
the Base Rent due hereunder for each Site to MATC for the remainder of the
then-current term for all of the Site Leases then in effect, provided, however,
that upon MATC's receipt of such prepaid rent in full, Lessee shall no longer be
in default with respect to the payment of any such Base Rent during the
then-current term.

      (f) In order to secure compliance of Lessee's payment obligations
hereunder, Lessee shall deliver to MATC a performance bond issued by a Mexican
bonding institution of repute, approved by MATC in writing, within twenty (20)
Business Days after the Commencement Date for each Site Lease, for an amount
equal to the aggregate amount of the monthly payments of the Base Rent and
Additional Rent due under the corresponding Site Lease for the subsequent twelve
(12) month period. Lessee shall provide MATC a renewal of such bond policies
yearly, no later than twenty (20) Business Days after the anniversary of the
Commencement Date, for an amount equal to the outstanding Base Rent and
Additional Rent payable through the subsequent twelve (12) month period, as
adjusted to take into account increases provided for in Section 5. MATC and
Lessee acknowledge and agree that any one Affiliate of Lessee may obtain the
foregoing bond in its name for and on behalf of and for the benefit of all or
any of its Affiliates hereunder.

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      6. RENT REDUCTIONS AND OTHER TENANTS.

      (a) The parties hereby agree and acknowledge that premises in each Site,
other than the Premises, may be rented to third parties (each an "OTHER TENANT")
by MATC, under terms and subject to the conditions established by MATC
consistent with MATC's obligations under Section 8 hereof. For each additional
lease agreement entered into by MATC with an Other Tenant that will use premises
on a Site to provide wireless telecommunication services (including, without
limitation, cellular, PCS, wireless local loop, paging, microwave and fiber
transmission), the Base Rent payable under the applicable Site Lease will be
reduced per month and per each such Other Tenant by the lesser of (i) US$200
(two hundred Dollars 00/100 U.S Cy.) or (ii) ten percent (10%) of the monthly
recurring rent paid by the Other Tenant. Notwithstanding the foregoing,
following July 25, 2003, no rental reductions pursuant to this Section 6(a),
other than those in effect as of July 25, 2003, in the amount in effect as of
July 25, 2003, shall be available to Lessee under this Agreement. For the
avoidance of doubt, the previous sentence shall not apply to Sites under the
2001 Purchase Agreement.

      (b) MATC shall use its commercially reasonable efforts to deliver within
twenty (20) Business Days following the end of each calendar quarter a statement
("QUARTERLY STATEMENT") setting forth, in reasonable detail (A) the amount of
Base Rent actually paid by Lessee with respect to such calendar quarter and the
amount of Additional Rent actually paid by Lessee with respect to such calendar
quarter, (B) the amount of Base Rent due from Lessee with respect to such
calendar quarter pursuant to this Agreement (i.e., taking into account, among
other things, the amount of the rent reductions under this Section 6) and the
amount of Additional Rent due from Lessee with respect to such calendar quarter,
and (C) the net amount (the "NET AMOUNT"), if any, due to MATC or Lessee, as
applicable. Within five (5) Business Days of delivery of a Quarterly Statement
the payee of the Net Amount shall provide payment instructions to the payor
specifying, among other things, whether payment of the Net Amount is to be in
U.S. Dollars or Mexican pesos. Within ten (10) Business Days of receipt of the
payment instructions, the payor shall remit the Net Amount to the other party by
wire transfer of immediately available funds in accordance with such payment
instructions. If no payment instructions are received within five (5) Business
Days of delivery of the Quarterly Statement, the Net Amount shall be paid in US
Dollars within fifteen (15) Business Days of delivery of the Quarterly Statement
by wire transfer of immediately available funds. If payment is to be made in
U.S. Dollars, it shall be made at the then current rate at which Mexican pesos
are exchangeable into U.S. Dollars as published by Banco de Mexico in the
Federal Official Gazette on the date of payment of the Net Amount. If Lessee
disputes the amounts set forth in the Quarterly Statement, Lessee shall deliver
written notice to MATC setting forth in reasonable detail the basis for such
dispute. If Lessee delivers such a dispute notice, Lessee and MATC shall
cooperate in good faith and use their commercially reasonable efforts to resolve
such dispute for a period of thirty (30) days following delivery of the dispute
notice. If the parties are unable to resolve such dispute within such thirty
(30) day period, the dispute shall be resolved in accordance with Section 22.12
of this Master Lease. Absent manifest error, any acceptance of the Net Amount by
Lessee shall act as a waiver of its right to dispute the amounts set forth in
the Quarterly Statement as provided in this Section 6(b).

                                       10
<PAGE>

      (c) During the term of this Agreement, MATC agrees to keep all usual and
proper records and books of account and all usual and proper entries relating to
this Agreement, and Lessee may conduct an audit of MATC's records applicable to
(i) the calculation of the rent reductions under this Section 6, (ii) the Per
Capita Share under Section 5(c) and (iii) MATC's compliance with the Prime
Leases and legal and regulatory requirements at each of the Sites (provided,
however, that any failure by MATC to comply will not be deemed a default under
this Agreement so long as Lessee does not suffer any materially adverse
consequence as a result thereof). Any such audit will be conducted by a
designated Lessee auditor or by an independent certified public accountant
selected by Lessee, and will be conducted only with reasonable advance written
request. The audit will be conducted during regular business hours and will be
conducted in such a manner as not to interfere with MATC's normal business
activities. Any fees or costs incurred by an independent certified public
accountant will be paid for by Lessee. Lessee recognizes and agrees that
information learned during an audit is confidential and that such information
may be used only in further disposition of the audit, including, without
limitation, to negotiate, prosecute, and resolve disputes.

      7. FACILITIES; UTILITIES; ACCESS.

      (a) Lessee, at its sole cost and expense, has the right to install,
maintain and operate on each of the Premises, Lessee's Improvements and
Equipment, which are owned by Lessee and/or any of its Affiliates, as more
specifically described in the applicable Site Lease, but in no event, except as
provided in Sections 7(c) and 7(g) respectively, may the structural loading
resulting from Lessee's Improvements and Equipment (i) (y) for 2001 Purchased
Sites, exceed the structural loading (e.g., wind load, weight, etc.) required on
the Tower for the installation of twelve (12) panel Allen Telecom ASPD-963
antennas, twelve (12) 1 5/8 inch coax cables, one (1) six foot diameter Andrew
solid microwave antenna and an associated 1 5/8 inch cable run and one (1) GPS
antenna located at the same height on the antenna structure and (z) for 2003
Purchased Sites, exceed the structural loading (e.g., wind load, weight, etc.)
required on the Tower for the installation of twelve (12) panel Allen Telecom
ASPD-963 antennas, twelve (12) 1 5/8 inch coax cables, two (2) six foot diameter
Andrew solid microwave antennas and an associated 1 5/8 inch cable run and one
(1) GPS antenna located at the same height on the antenna structure (as
applicable, the "MAXIMUM EQUIPMENT"), (ii) extend beyond the Premises or (iii)
exceed two (2) microwave antennas (for Sites purchased pursuant to the 2003
Purchase Agreement) or one (1) microwave antenna (for Sites purchased pursuant
to the 2001 Purchase Agreement) (in each case, the "MAXIMUM MICROWAVE
ANTENNAS"). Without MATC's prior written consent, Lessee shall not have the
right to relocate Lessee's Improvements and Equipment to any location on a Site.
All construction and installation work necessary or convenient for the use of
Lessee's Improvements and Equipment shall be performed in a good and workmanlike
manner. Title to Lessee's Improvements and Equipment shall be held by Lessee.
Lessee's Improvements and Equipment shall remain Lessee's personal property and
are not fixtures. Notwithstanding anything to the contrary in this Master Lease,
in the event that Lessee elects to install less than the Maximum Equipment as of
the Commencement Date, Lessee shall reserve the right at any time during the
Initial Term or any Renewal Term thereof, to install additional improvements and
equipment (or substitute different improvements and equipment) within the
Premises for no additional rent up to the Maximum Equipment, subject to the
provisions of Sections 8 and 15 herein; provided that such additional or
substitute improvements

                                       11
<PAGE>

and equipment will not (i) create interference with the then-existing
improvements and equipment of any Other Tenant upon installation or (ii) exceed
the structural loading (e.g., wind load, weight, etc.) of the Maximum Equipment
assuming the Maximum Equipment is installed at the height of the initial
installation of Lessee's Improvements and Equipment (the "Base Loading").

      (b) Lessee shall have the right to remove Lessee's Improvements and
Equipment under any Site Lease at any time before the expiration or earlier
termination of the applicable Site Lease so long as Lessee is not then in
default. The authorization to remove all or part of Lessee's Improvements and
Equipment prior to the termination of the Master Lease and/or the respective
Site Lease shall not be interpreted as a release of Lessee's responsibility to
perform its respective obligations under such agreements and, accordingly,
unless otherwise agreed, Lessee shall continue to pay the same Base Rent and
Additional Rent, for the same term, as it was prior to removal of such
equipment.

      (c) If Lessee desires to install additional improvements and equipment at
any Site on space on the applicable structure outside of the Premises or that
will exceed the structural capacity (e.g., wind load, weight, etc.) on the Tower
required for the Maximum Equipment or if Lessee desires to install more than the
Maximum Microwave Antennas ("NEW EQUIPMENT"), MATC and Lessee shall negotiate in
good faith the terms of a site lease providing for the installation of such New
Equipment on the applicable Site; provided, however, that MATC's obligation to
negotiate in good faith for the lease of additional space and/or loading in
excess of Base Loading on a Site shall be conditioned upon the existence of
space on such structure which is unoccupied and not leased under, or otherwise
covered by, another agreement (or an agreement then being negotiated by MATC)
permitting another third-party to use or occupy such portion of the applicable
Site ("AVAILABLE SPACE") and the obtaining of any necessary Permits for the
installation of such New Equipment. The rent payable by Lessee for the use of
additional space and/or loading for the installation of such New Equipment will
be based upon the additional loading resulting from such New Equipment, pursuant
to the following formula: first, the Base Loading will be determined; second,
the loading resulting from the New Equipment will be determined based upon the
applicable tower manufacturer's specifications and the proposed height of such
New Equipment; and third, the Additional Rent will be determined based upon the
loading resulting from New Equipment in proportion to the Base Loading (for
example, assuming that the Base Load factor is 100 and the wind load factor of
such New Equipment would be 50 and the Base Rent at such time is equal to $2,000
per month, the additional rent would be equal to $1,000 per month (50/100 times
$2,000). Notwithstanding the foregoing, in the event that the New Equipment that
Lessee elects to install upon any Site pursuant to this Section 7(c) is (i) a
paging antenna, the Additional Rent to be paid by Lessee shall be four hundred
six dollars (US$406.00) per set of omnidirectional and GPS antenna or (ii) one
(1) additional microwave antenna (which does not exceed the loading required for
installation of a six foot diameter Andrew solid microwave antenna) per Site,
the additional rent to be paid by Lessee shall be two hundred three dollars
(US$203.00) per microwave antenna, each subject to annual increases in
accordance with Section 5(b). In the event that the New Equipment that Lessee
elects to install upon any applicable Site is a microwave antenna in addition to
the microwave antenna permitted by the immediately preceding sentence, the
Additional Rent to be paid by Lessee per microwave antenna shall be calculated
in accordance with the formulas

                                       12
<PAGE>

contained in Exhibit E attached hereto, as such Exhibit E may be mutually
amended from time to time. Additional Rent pursuant to this Section 7(c) (but
not pursuant to Section 5(c)) shall be subject to annual increases in accordance
with Section 5(b).

      (d) Lessee shall timely pay for the electricity used in its operations at
the rate charged by the servicing utility company. Lessee shall draw electricity
by submeter and other utilities from the existing utilities on the Site, unless
otherwise mutually agreed. Any easement necessary for such power or other
utilities will be at a location reasonably acceptable to MATC and the servicing
utility company, but shall be subject to MATC's rights under the applicable
Prime Lease.

      (e) Lessee shall have the right to install or temporarily place, as
required, an emergency gasoline, butane, diesel or other fuel-powered
generator(s) on the Premises, at Lessee's sole cost and expense, and Lessee
covenants that such installation or placement and use shall be in compliance
with any applicable federal, state, or local environmental, health, fire,
community awareness, safety laws or other applicable laws or regulations, now or
hereafter enacted or promulgated by any Governmental Authority or court ruling
having jurisdiction over the relevant Site, including, without limitation, any
applicable guidelines promulgated by the environmental protection authorities.

      (f) Lessee, Lessee's employees, agents and subcontractors may enter on or
across the Site twenty four (24) hours a day, seven (7) days a week, at no
charge, to obtain entry into the Premises for the purpose of constructing,
installing, operating, maintaining and repairing those parts of Lessee's
Improvements and Equipment as are ground based, except as otherwise expressly
provided in the Prime Lease. Lessee shall not, without prior notice to and
approval (which shall not be unreasonably withheld or delayed) from MATC,
perform or arrange to be performed normally scheduled installation or repair of
Lessee's Improvements and Equipment on a Tower and MATC shall have the right to
have a representative present during such installation and repair. Any emergency
installation, maintenance or repair of Lessee's Improvements and Equipment on
the Tower shall be performed only with prior verbal notice to MATC. Such access
shall be in accordance with the procedures set forth in Exhibit D attached
hereto, as such Exhibit D may be mutually amended from time to time, and such
access route shall be as shown in the applicable Site Lease. Notwithstanding the
foregoing, MATC reserves the right, in its reasonable discretion, to refuse to
permit any non-qualified person or company to climb any Tower.

      (g) Notwithstanding any other provision of this Agreement, in connection
with Lessee's Improvements and Equipment installed on a Tower, Lessee's
microwave antennas may extend outside of the Premises at no additional rental
cost so long as such equipment (i) does not create interference with the
then-existing improvements and equipment of any Other Tenants and (ii) does not
exceed the Base Loading. If MATC receives a bona fide written offer that it is
considering accepting from a potential broadband collocation tenant ("POTENTIAL
TENANT") for space on a Tower located outside of the Lessee's Premises which is
being utilized by Lessee for no additional rent in accordance with this Section
7(g) or if Lessee's Improvements and Equipment located outside of the Premises
would interfere with such Potential Tenant's equipment, then before accepting
the offer MATC shall deliver a written notice to Lessee ("NOTICE OF OFFER")
offering to lease to Lessee the space being offered to the Potential Tenant

                                       13
<PAGE>

("POTENTIAL TENANT SPACE") for the same price and on the same terms specified in
the Notice of Offer. The Notice of Offer shall contain the price, a description
of the Potential Tenant Space, and any other relevant terms of the offer. Lessee
may elect to lease the Potential Tenant Space on the terms contained in the
Notice of Offer by providing a written notice to MATC within the five (5)
Business Day period immediately following receipt of the Notice of Offer. If
Lessee notifies MATC Digital of its election to lease the Potential Tenant Space
within such five (5) Business Day period, then the terms included in the
Potential Tenant Notice shall be binding on the parties and the parties shall
execute a revised or new Site Lease reflecting such terms within ten (10)
Business Days immediately following such acceptance. If Lessee has not elected
to lease the Potential Tenant Space on the terms contained in the Notice of
Offer within such five (5) Business Day period, then Lessee's right of first
refusal on such space shall terminate and MATC may lease the Potential Tenant
Space to the Potential Tenant on terms that are in the aggregate no more
favorable to the Potential Tenant than those contained in the Notice of Offer.
If MATC does not execute a definitive agreement with the Potential Tenant within
thirty (30) days from the expiration of Lessee's right of first refusal, then
MATC must again offer the space to Lessee on the terms provided in this Section
7(g). If Lessee has not elected to lease the Potential Tenant Space, within five
(5) Business Days following the expiration of Lessee's right of first refusal,
Lessee shall, at its sole cost and expense, reconfigure its equipment such that
its microwave antennas located outside of the Premises no longer extend into
Potential Tenant Space or interfere with the Potential Tenant's equipment.

      8. NON-INTERFERENCE.

      In the event that the operations of Lessee (including any subsequent
modifications or installations) under any Site Lease interfere with the then
pre-existing transmitting or receiving of radio, television, or electronic
signals by MATC or Other Tenants (or if the Lessee's microwave equipment located
outside of the Premises pursuant to Section 7(g) interferes at any time with
MATC's or an Other Tenant's equipment), Lessee shall cause the interference to
be eliminated within forty-eight (48) hours, for material interference, and
fifteen (15) Business Days if otherwise measurably adverse, at no cost to MATC
or Other Tenants. In the event such interference does not cease within the
applicable time period, MATC may terminate the applicable Site Lease, or shut
off Lessee's Improvements and Equipment. This provision shall not apply to test
periods where the source of the interference is being determined for purposes of
suppression. In the event that, with respect to Lessee's initial installation on
any given Site (other than microwave antennas extending beyond the Premises) or,
with respect to any subsequent modification of Lessee's Improvements and
Equipment or operations, any devices installed by MATC after such modification
shall interfere with Lessee's then-existing transmission or reception, MATC
shall cause the interference to be eliminated within forty-eight (48) hours, for
material interference, and fifteen (15) Business Days if otherwise measurably
adverse, at no cost to Lessee.

      In the event such interference does not cease within the time periods
specified above, the parties acknowledge that continuing interference will cause
irreparable injury to the party experiencing such interference and such party
shall have all rights available under applicable law to cause such interference
to cease.

                                       14
<PAGE>

      9. TAXES.

      As provided in Section 5(c), Lessee shall pay to MATC its Per Capita Share
(as defined in Section 5(c) hereof) of all real estate taxes and other taxes,
duties or charges of similar nature imposed on the Sites. To that effect, MATC
shall make the required calculations and inform Lessee the amounts payable
together with any supporting documentation. Lessee shall reimburse MATC for any
increases in real property taxes that are assessed as a direct result of
Lessee's Improvements and Equipment to the Sites. As a condition of Lessee's
obligation to pay such tax increases, MATC shall provide Lessee the
documentation from the relevant taxing authorities indicating that the increase
is due to Lessee's Improvements and Equipment. Any other taxes, levies or rights
imposed by any authorities as a result of the performance of the obligations
under the Original Master Lease, this Master Lease or each Site Lease, will be
borne by the corresponding party, at its sole expense.

      10. DEFAULT; TERMINATION.

      (a) Either party shall be in default under an applicable Site Lease if the
party fails to perform any material duty or obligations under this Master Lease
or such Site Lease, in respect of a Site or any Premises, and does not cure or
remedy such failure to perform within twenty (20) Business Days after receipt of
written notice with respect thereto; provided, however, that if such failure to
perform shall require a longer period to cure, then such cure period shall be
extended for such time as is reasonably necessary to cure such failure to
perform (not to exceed forty-five (45) Business Days), but only so long as such
efforts to cure are commenced within ten (10) Business Days after receipt of
written notice from the other party and thereafter proceed diligently and in
good faith. Notwithstanding the foregoing, in no event shall the time within
which a party may cure a failure in the payment of money exceed a single ten
(10) Business Day period following written notice of such failure, without
extension; provided, however, that the defaulting party shall be required to pay
any overdue money after such ten (10) Business Day period has elapsed by check
and if such check is accepted and actually cashed or deposited by the
non-breaching party (so long as such check also clears), then the receipt of
such funds shall be deemed a waiver by the non-breaching party of such default.

      (b) Upon the occurrence of a default, the non-defaulting party may pursue
any and all remedies available under applicable law and any one or more of the
following remedies, separately or concurrently or in any combination, to the
extent compatible under applicable law, without further notice or demand
whatsoever:

            (i) Termination of the applicable Site Lease by giving the
      defaulting party written notice of such termination, in which event the
      applicable Site Lease shall be terminated at the time designated in the
      notice without any further judgment or judicial declaration; and

            (ii) The recovery from the defaulting party of all damages, costs
      and expenses incurred by the non-defaulting party in enforcing and
      compensating its rights and remedies under this Master Lease and the
      applicable Site Lease, including reasonable attorneys' fees and expenses.

                                       15
<PAGE>

      (c) Notwithstanding the foregoing, if Lessee breaches any of its material
obligations under ten percent (10%) or more of the Site Leases under this
Agreement and the MLA for BTS Sites, collectively, then in effect in any
particular Region during any consecutive six (6) month period during the Term,
MATC shall have the right to terminate this Master Lease and any other or all of
the Site Leases executed under the terms of this Master Lease with respect to
such Region; provided, however, that if MATC has previously exercised its right
to accelerate the rental payments due for the Region affected hereunder pursuant
to Section 5(e) above, MATC shall not have the right to terminate the relevant
Site Leases which have been pre-paid. In addition, if Lessee is in default on
the payment of Base Rent and/or Additional Rent for three (3) months or more
with respect to five percent (5%) or more of the Site Leases under this
Agreement, then so long as MATC has not exercised its right to accelerate rental
payments under Section 5(e), MATC may terminate this Master Lease and any other
or all of the Site Leases executed under the terms of this Master Lease.

      (d) The termination of an applicable Site Lease by reason of a party's
default shall not relieve the defaulting party of any of its duties and
obligations accrued under this Master Lease in respect of such Site Lease or any
other Site Lease, prior to the effective date of such termination.

      (e) At the expiration or termination of an applicable Site Lease for any
reason, Lessee shall surrender to MATC the Premises, remove Lessee's
Improvements and Equipment, and shall restore the Premises to substantially the
same condition existing on the Commencement Date, except for ordinary wear and
tear. If Lessee fails to remove Lessee's Improvements and Equipment as required,
Lessee's Improvements and Equipment will, subject to fifteen (15) days prior
written notice and subject to the rights of the Financing Secured Parties
described in Section 13(c)(i), be subject to disconnection, removal and disposal
by MATC. In such event, Lessee will pay to MATC upon written demand therefor,
the disconnection, removal and storage expenses incurred by or on behalf of MATC
including, without limitation, the repair of any damage to the Premises or Site
caused by such removal. If Lessee's Improvements and Equipment are not claimed
by Lessee within thirty (30) days following written notice from MATC to Lessee
of its removal, subject to the rights of the Financing Secured Parties described
in Section 13(c)(i), MATC is hereby authorized by Lessee to take any steps
necessary, subject to any existing lien, security interest or other encumbrance,
to sell all or any portion of Lessee's Improvements and Equipment, and Lessee
shall execute any documents necessary to effect such transfer. In the event
Lessee's Improvements and Equipment remain on the Premises following termination
or expiration of the applicable Site Lease (even if it has been disconnected),
Lessee shall pay to MATC holdover rent equal to one hundred and twenty-five
percent (125%) of the then effective Base Rent, pro-rated from the date of
termination to the date Lessee's Improvements and Equipment are removed from the
Premises by Lessee. The parties hereby specifically acknowledge that MATC will
be under no obligation to repay Lessee for any construction, improvements or
work performed on a Site by Lessee, and Lessee hereby waives the provisions of
articles 2423 and 2424 of the Federal Civil Code and the applicable provisions
of the Civil Codes of the jurisdictions in which any Site is located.
Notwithstanding anything to the contrary herein, the notice requirements
outlined in this Section 10(e) shall not apply to the extent that they conflict
with the provisions of the applicable Prime Lease pursuant to its termination or
expiration.

                                       16
<PAGE>

      (f) [INTENTIONALLY OMITTED]

      (g) Subject to Section 10(j), upon no less than thirty (30) days prior
written notice (unless a lesser period of time is otherwise required by law),
either party hereto may terminate the applicable Site Lease without any further
obligation by either party to the other if any law, ordinance, regulation or
directive of any governmental or regulatory authority hereinafter enacted or
ordered prohibits Lessee's or MATC's use of the Premises so long as such
governmental action is not the result of any action or inaction by the
terminating party.

      (h) MATC will provide Lessee with a copy of any notice of default received
by MATC under any Prime Lease in the event that MATC does not intend to or can
not cure any such default during the applicable cure period provided for in the
Prime Lease or of any notice, complaint, order or decree that will (or could)
adversely affect Lessee's ability to operate its wireless communications
facility from the Site or will (or could) adversely affect any right or remedy
of Lessee hereunder. Any failure by MATC to deliver notice pursuant to this
Section shall not be deemed a default under this Agreement so long as Lessee
does not suffer any materially adverse consequence as a result thereof.

      (i) Notwithstanding anything to the contrary in this Agreement, in the
event that MATC fails to comply with the provisions of a Prime Lease, any
Governmental Requirements (other than failure to obtain Tower Site Permits that
Lessee or its affiliates were required to obtain prior to Closing), or its
maintenance or repair obligations hereunder and Lessee's rights hereunder shall
(or could) be materially and adversely affected by a failure to comply, Lessee
(in addition to any other rights and remedies it may be entitled to hereunder)
will be authorized, following no less than five (5) Business Days prior written
notice to MATC (unless during such period MATC diligently commences and pursues
the cure of such failure), to pay any reasonable amount required to cure such
failure or, if applicable, commence and prosecute any and all reasonable action
or actions necessary to cure such failure as may be available to MATC. Following
any such payment by Lessee, Lessee will be entitled to withhold the full amount
thereof from installments of rent or other payments next owing under this
Agreement until such amount and charge have been fully credited. Any dispute as
to the obligation to pay any such amount or pursue any specific action pursuant
to this Section 10(i), will be resolved in accordance with Section 22 hereof.

      (j) In the event that a tower structure upon which the Premises are
located at any Site must be removed, dismantled or otherwise becomes unusable
because the applicable Tower Site Permits for a Site were required to be
obtained by Lessee or its Affiliates prior to the Closing (as defined in the
Purchase Agreement) of such Site, but were not obtained by Lessee or such
Affiliates, then (i) the associated Site Lease shall be deemed to have been
terminated contemporaneously therewith, (ii) Lessee shall promptly indemnify
MATC, which indemnification shall be paid (A) if Base Rent is being paid
annually, then annually in advance on the anniversary of the applicable
Commencement Date, beginning on the date of such deemed termination and ending
on the nine year anniversary of the applicable Commencement Date (i.e., payment
shall be through the remainder of the Initial Term), or (B) if Base Rent is
being paid monthly, then monthly in advance on the first of each month beginning
on the date of such deemed termination and ending on the month immediately prior
to the ten (10) year anniversary

                                       17
<PAGE>

of the Commencement Date (i.e., payment shall be through the remainder of the
Initial Term); in each case in an amount equal to the rent that would have been
payable to MATC under the applicable Site Lease. To the extent that Lessee has
prepaid rent corresponding to any periods after the deemed termination, such
prepaid rent shall count toward Lessee's indemnity obligation described in this
Section 10(j). The Indemnification described in this Section 10(j) shall be in
addition to any other indemnification provided for in this Section 10 or any
other section of this Agreement and Lessee further waives any right to claim
such event as a force majeure event under the applicable provisions of the
Federal Civil Code and its corresponding articles of the Civil Codes for the
Federal District and the States of Mexico.

      11. EXPROPRIATION.

      If the whole or any substantial part of a Site shall be taken by any
public authority under the power of eminent domain (expropiacion) so as to
materially interfere with Lessee's use and occupancy, then the Site Lease shall
terminate as to such Site so taken. Any Base Rent covering the period after the
effective date of termination paid in advance shall be refunded to Lessee within
thirty (30) days of Lessee's written demand.

      12. INSURANCE.

      (a) Each Party shall carry during the term of each Site Lease, at its own
cost and expense, the following insurance with respect to the Sites and the
Premises: (i) "All Risk" property insurance which insures the insuring party's
property for its full replacement cost; and (ii) comprehensive general liability
insurance with a commercial general liability endorsement having a minimum limit
of liability of US$1,000,000.00 (one million Dollars 00/100 U.S. Cy.) with a
combined limit for bodily injury and/or property damage for any one occurrence,
and (iii) excess/umbrella coverage of US$5,000,000.00 (five million Dollars
00/100 U.S. Cy.) MATC agrees to use its reasonable best efforts to require all
Other Tenants who execute lease agreements with MATC on or after the date first
written above to maintain insurance coverage comparable (based on such Other
Tenant's equipment installation and use of a Site) to the coverage limits set
forth in this Section 12(a).

      (b) Each Party shall name the other as an additional insured (in the case
of Lessee, such rights of MATC to be subject to the rights of the Financing
Secured Parties described in Section 13(c)(i)) under its liability policy and
require its insurance company to endeavor to give at least thirty (30) days'
written notice of termination or cancellation of the policy to the additional
insured. A certificate of such insurance, together with such endorsement, shall
be delivered to the additional insured within thirty (30) days from the
Commencement Date for each Site Lease and before the expiration of any term
thereof, from a licensed insurance company. All insurance certificates must
contain an undertaking by the agents or brokers to notify the other party in
writing not less than thirty (30) days before any material change, reduction in
coverage, cancellation or termination of the insurance.

      (c) Lessee shall cause any contractor retained by Lessee to maintain in
full force and effect during the term of any maintenance, work or repairs
performed on Lessee's behalf at any Site, insurance satisfying the coverage
requirements described in Section 12(a) and to deliver,

                                       18
<PAGE>

prior to the commencement of such work, an insurance certificate naming MATC as
an additional insured. Lessee shall be solely responsible and liable to MATC for
Lessee's failure to obtain or deliver to MATC the required insurance
certificates from Lessee's approved contractor.

      13. ASSIGNMENT.

      (a) This Master Lease or any Site Lease may be sold, assigned or
transferred, in whole or in part, by MATC (i) to any subsidiary and/or affiliate
of MATC; (ii) in the event of a sale, assignment or transfer of all or
substantially all of MATC's assets or equity interests in one or a series of
related transactions; (iii) in the event of a sale, assignment or transfer of
all or substantially all of MATC's assets located within a particular Mexican
Region (as such regions are commonly defined with respect to communication
services as of the date of the execution of this Master Lease and hereinafter
referred to as a "REGION(S)"); (iv) pursuant to any merger, stock transfer, sale
of all or substantially all of the assets of or other corporate reorganization
involving any of MATC's parent companies; and (v) to any lender of MATC if such
lender becomes a successor to its business through foreclosure in accordance
with Section 13(d), provided, however, that, except in connection with a merger,
stock transfer, sale of all or substantially all of the assets of or other
corporate reorganization involving American Tower Corporation, MATC's ultimate
parent entity (or its successor-in-interest), MATC may in no event assign all or
any part of this Master Lease or any Site Lease to any of the following of
Lessee's competitors: Telcel, Nextel or Telefonica (or any of their
successors-in-interest), or any other person domiciled in Mexico who is an
Affiliate of such competitor as of the date of this Agreement; provided,
further, that if Lessee is in payment default under this Agreement, MATC may
freely sell, assign or transfer this Master Lease or any Site Lease, in whole or
in part, without restriction. Any other assignment of this Master Lease or any
Site Lease shall require the prior written consent of Lessee, which consent
shall not be unreasonably withheld, conditioned or delayed.

      (b) This Master Lease or any Site Lease may not be sold, assigned or
transferred, in whole or in part, by Lessee without the prior approval or
consent of MATC; provided, however, that notwithstanding anything to the
contrary contained herein, (i) Lessee may sublease any space on the Premises,
transfer any of its rights and/or obligations under this Master Lease, Lessee's
Improvements and Equipment and/or any Site Lease to any subsidiary and/or
Affiliate whose ownership or voting percentage is not modified to less than
forty-five percent (45%) of the current ownership or voting percentage by any
act or series of acts subsequent to the assignment that may cause Lessee to lose
such percentage within two (2) years from the date of the assignment, provided
that the respective permitted sublessee or assignee must agree in writing,
before taking possession of the subleased Premises, to be bound by all the terms
and conditions of this Master Lease and the applicable Site Lease; (ii) in the
event that such sale, assignment or transfer is associated with the sale of all
or substantially all of Lessee's assets located within a particular Region, MATC
may not unreasonably withhold, condition, or delay such consent; (iii) Lessee
may sell, assign or transfer its rights under this Master Lease or any Site
Lease pursuant to any merger, stock transfer, sale of all or substantially all
of the assets of or other corporate reorganization involving any of Lessee's
parent companies; and (iv) Lessee may grant a security interest in this Master
Lease in favor of the Financing Secured Parties as contemplated by Section
13(c)(i). Any sale, transfer or assignment by Lessee under or pursuant to
subsections (ii) or (iii), shall be contingent upon Lessee assigning the Master
Lease and all of the Site Leases

                                       19
<PAGE>

associated therewith (or, in the case of subsection (ii), all of the Site Leases
in the applicable Region) and the assignee assuming all of the obligations under
the Master Lease and all of such Site Leases (or, in the case of subsection
(ii), all of the Site Leases in the applicable Region). No sale, transfer or
assignment of the Master Lease or any Site Lease hereunder will release Lessee
from any obligations or liabilities hereunder or under the assigned Site Lease;
provided, however, that Lessee shall be released of such obligations and
liabilities if (i) the total assets and total revenue of such successor entity
are at least equal to that of Grupo Iusacell on a consolidated basis, (ii) the
successor entity agrees in writing to be bound by the terms and conditions of
this Master Lease and the applicable Site Leases and (iii) the successor entity
is not an Affiliate of the assigning party. In no event may Lessee sublease,
sublicense, or permit shared use of the Premises by any party other than an
Affiliate of Lessee in accordance with subsection 13(b)(i) herein; provided,
however, that in the event that the applicable antenna structure is fully loaded
and can not be structurally modified to accommodate any additional equipment,
Lessee may sublease or sublicense the Premises to a third party with the prior
written consent of MATC, which consent shall not be unreasonably withheld or
delayed.

      (c) MATC hereby acknowledges and consents to the security interests
granted by Lessee or its affiliates in this Master Lease, any Site Lease and any
of Lessee's Improvements and Equipment in favor of (i) The Chase Manhattan Bank
(currently known as JPMorgan Chase Bank) ("CHASE") as lender and as collateral
agent and administrative agent for the lenders (the "CHASE LENDERS") listed in
the mortgages, under those certain mortgages granted by means of (X) notarial
deed 5,114, dated December 1, 1997, granted before Mr. Francisco Hugues Velez,
Notary Public Number 212 in the Federal District, registered under commercial
numbers before the applicable Public Registry of Commerce 129,279, 126,502,
168,528, 177,150, 120,042, and 132,047, executed by and among each of the
companies mentioned therein as mortgagors and Chase as mortgagee, as amended and
restated under the First Amendment to the Mortgage Agreement granted by means of
notarial deed 8,824, dated April 15, 1999, granted before Mr. Francisco Hugues
Velez, Notary Public Number 212 in the Federal District executed by and among
the companies mentioned therein as mortgagors and Chase as mortgagee (the "FIRST
AMENDED MORTGAGE"), and the Second Amendment to the Mortgage Agreement granted
by means of notarial deed 3,196, dated March 29, 2001, granted before Mr.
Francisco Hugues Velez, Notary Public Number 212 in the Federal District
executed by and among the companies mentioned therein as mortgagors and Chase
and the First Union National Bank as mortgagees (the "SECOND AMENDED MORTGAGE"),
and (Y) notarial deed 6,283, dated April 30, 2002, granted before Mr. Francisco
Hugues Velez, Notary Public Number 212 in the Federal District, registered under
commercial numbers before the applicable Public Registry of Commerce 298,914,
executed by and among Portatel del Sureste, S.A. de C.V. and Portatel
Comercializadora, S.A. de C.V. as mortgagors and Chase and First Union National
Bank as mortgagees (the "PORTATEL MORTGAGE") and (ii) First Union National Bank
("FIRST UNION"), as trustee and agent or representative of the holders under the
Senior Note Indenture, granted by means of the Second Amended Mortgage and the
Portatel Mortgage (First Union, Chase and the Chase Lenders are collectively
referred to as the "FINANCING SECURED PARTIES"). Lessee may, upon prior written
notice to MATC, mortgage or grant a security interest in Lessee's Improvements
and Equipment to any bona fide unaffiliated institutional lender in connection
with any bona fide financing by Lessee, and may assign its rights to Lessee's
Improvements and Equipment to any such

                                       20

<PAGE>

mortgagees or holders of security interests including their successors or
assigns (hereinafter, with the Financing Secured Parties, collectively referred
to as "LESSEE MORTGAGEES"). In such event, MATC shall execute such consent to
leasehold financing as may reasonably be required by Lessee Mortgagees, in which
MATC will agree to notify Lessee and the Lessee Mortgagees simultaneously of any
default by Lessee and to give Lessee Mortgagees the same right to cure any
default as Lessee except that the cure period for any Lessee Mortgagee shall not
be less than ten (10) days after receipt of the default notice.

      (d) Lessee acknowledges and agrees that MATC has or may in the future
enter into financing arrangements with financing entities ("MATC'S LENDERS")
evidenced by credit agreements and other documents (as may be amended from time
to time) pursuant to which MATC may grant to MATC's Lenders, as security
interest in connection therewith, certain rights to assume MATC's contractual
obligations hereunder; provided, however, that any such security interest or
right shall in all instances be subject to the Subordination Agreement executed
on even date herewith. In the event that MATC's Lenders become a successor to
MATC's business through foreclosure or otherwise, Lessee shall continue to
perform its respective obligations under this Agreement in favor of MATC's
Lenders if and to the extent that MATC's Lenders continue to perform MATC's
obligations under this Agreement; provided, however, that nothing in this
paragraph shall be deemed to restrict or limit Lessee's rights and remedies with
respect to any default under this Agreement by MATC or, as its successor, MATC's
Lenders.

      14. WARRANTY OF TITLE AND QUIET ENJOYMENT; COMPLIANCE WITH LAWS.

      (a) MATC warrants that: (i) MATC owns or leases the Site and the Tower
located thereon (if any) and will have rights of access thereto; (ii) MATC has
full right to make and perform this Master Lease; and (iii) MATC covenants and
agrees with Lessee that, according to article 2412 of the Federal Civil Code and
the applicable provisions of the Civil Codes of the jurisdictions where any Site
is located, upon Lessee paying the Base Rent and Additional Rent and observing
and performing all the material terms, covenants and conditions on Lessee's part
to be observed and performed, Lessee may peacefully and quietly have, hold and
enjoy possession and use of each of the Premises. Notwithstanding anything to
the contrary herein, (i) no representation, warranty or covenant made by MATC in
this Master Lease shall be enforceable by Lessee against MATC (or be deemed
breached by MATC hereunder) in the event that such representation, warranty or
covenant (x) is contrary to any disclosure made by Lessee to MATC pursuant to
the Purchase Agreements, or (y) relates to or existed during any period of time
prior to the Closing, and (ii) any representation, warranty or covenant made by
MATC in this Master Lease shall be subject to and limited by any similar
representation, warranty, and covenant made by Lessee to MATC under the Purchase
Agreements.

      (b) In the performance by each party to this Agreement of its respective
obligations hereunder, the parties recognize and acknowledge that each party
hereto shall be responsible for the personnel it employs to perform its
respective obligations hereunder, including, without limitation, their ordinary
and extraordinary salaries, vacations, Christmas bonus (aguinaldo), seniority
payments (prima de antiguedad), disability payments, severance payments,
contributions to the IMSS and INFONAVIT and any other existing obligation
derived from the Federal Labor Law (Ley Federal de Trabajo) (collectively,
"LABOR OBLIGATIONS"). Each party

                                       21

<PAGE>

shall have no responsibility for the other party's Labor Obligations or to the
other party's personnel or otherwise, and each party agrees to indemnify, defend
and hold harmless the other party and its respective Affiliates, and their
directors, officers and employees, from and against all Losses based upon any
claim arising out of Labor Obligations. In the performance by the parties of
their respective obligations under this Agreement, each of MATC and Lessee agree
to comply with any and all applicable laws of Mexico and, as applicable, the
United States. Without limiting the generality of the foregoing, MATC and Lessee
each agree, in the performance of their respective obligations hereunder, to
comply with the provisions of the Foreign Corrupt Practices Act of the United
States.

      (c) Notwithstanding the provisions of this Section 14, any Site Lease
hereunder may be terminated, without any further obligation by either party to
the other, by Lessee, from the period beginning on the date first written above
and ending ten (10) years thereafter ("TERMINATION PERIOD"), in the event that a
man-made obstruction constructed subsequent to Lessee's installation (or later
modification) adversely affects Lessee's RF requirements with respect to the
operation of such affected equipment; provided, however, that in no event may
Lessee terminate more than an aggregate of five percent (5%) of all of the Site
Leases executed by Lessee hereunder during the Termination Period pursuant to
this Section 14(c).

      15. MAINTENANCE AND REPAIRS.

      (a) Lessee shall perform all repairs necessary or appropriate to keep
Lessee's Improvements and Equipment on or about the Premises or located on any
appurtenant rights-of-way or access to the Premises in good and tenantable
condition. Damage to Lessee's Improvements and Equipment resulting from the acts
or omissions of MATC shall be repaired by MATC, at MATC's cost and expense
unless otherwise provided herein.

      (b) MATC, at MATC's sole cost and expense, shall maintain the Sites and
its improvements thereto in good order and repair, except acts resulting from an
act of God or force majeure (caso fortuito o fuerza mayor) which shall be
repaired by MATC as promptly as is practical under the circumstances; provided,
however, that if Lessee's ability to provide service to its customers through
Lessee's Improvements and Equipment is negatively affected, MATC shall commence
the repair of the facilities within twenty-four (24) hours and shall complete
such repairs within the time period reasonably necessary to effect such repairs
under the circumstances following written notice from Lessee thereof. Damage
resulting from the acts or omissions of Lessee shall be repaired by Lessee, at
Lessee's cost and expense unless otherwise provided herein.

      16. MISCELLANEOUS.

      (a) Entire Agreement. This Master Lease, the applicable Site Leases and
the Purchase Agreement and all schedules and exhibits hereto or thereto
constitute the entire agreement and understanding between the parties, and
supersedes all offers, negotiations and other agreements concerning the subject
matter contained herein. Any amendments to this Master Lease or any Site Lease
must be in writing and executed by both parties.

                                       22

<PAGE>

      (b) Severability. If any provision of this Master Lease is invalid or
unenforceable with respect to any party, the remainder of this Master Lease or
the application of such provision to persons other than those as to whom it is
held invalid or unenforceable, shall not be affected and each provision of this
Master Lease shall be valid and enforceable to the fullest extent permitted by
law.

      (c) Binding Effect. This Master Lease shall be binding on and inure to the
benefit of the successors and permitted assignees of the respective parties.

      (d) Notices. Any notice or demand required to be given herein shall be
made by recognized overnight courier to the address of the respective parties
set forth below:

      GRUPO IUSACELL:            Grupo Iusacell, S.A. de C.V.,
                                 Prol. Paseo da la Reforma 1236, 4th Floor
                                 Col. Santa Fe, 05348 Mexico, D.F.
                                 Attention: Vice President/Technical Operations
                                 Fax No.: (011) (525) 109-5407

      IUSACELL ARRENDADORA, S.A. DE C.V.:

                                 Prol. Paseo de la Reforma 1236, 4th Floor
                                 Col. Santa Fe, 05348 Mexico, D.F.
                                 Attention: Vice President/Technical Operations
                                 Fax No.: (011) (525) 55-109-5407

      With a copy to:            Grupo Iusacell Celular, S.A. de C.V.
                                 Prol. Paseo da la Reforma 1236, PH
                                 Col. Santa Fe, 05348 Mexico, D.F.
                                 Attention: General Counsel
                                 Fax No.: (011) (525) 55-109-5772

      MATC:                      MATC Celular, S. de R.L. de C.V.
                                 MATC Digital, S.de R.L. de C.V.
                                 Ejercito Nacional 904, Piso 17
                                 Col. Palmas Polanco
                                 11560, Mexico, D.F.
                                 Attn: Lawrence Gleason
                                 Fax: (011) (525) 55-240-2006

      With a copy to:            American Tower Corporation
                                 116 Huntington Avenue
                                 Boston, MA  02116
                                 Attention: General Counsel
                                 Fax No.: (617) 375-7575

                                         - and-

                                       23

<PAGE>

                                 American Tower International
                                 Galleria 75 Office Park, Suite 205
                                 3200 Cobb Galleria Parkway
                                 Atlanta, Georgia 30339
                                 Attention: Dan Brooks
                                 Fax No.: (770) 952-4999

      MATC or Lessee may from time to time designate any other address for this
purpose by written notice to the other party. All notices hereunder shall be
deemed received upon actual receipt.

      (e) Governing Law. This Master Lease shall be governed, to the extent
applicable, by the Federal Civil Code and other applicable federal laws of the
United Mexican States ("MEXICO"). The Site Leases shall be governed by the laws
of the jurisdiction on which the corresponding Sites are located as specified in
each Site Lease. If a term in a Site Lease conflicts with the terms of the
Master Lease, the Master Lease shall govern.

      (f) [INTENTIONALLY OMITTED]

      (g) Counterparts. This Master Lease, each Site Lease and all Exhibits to
this Master Lease or any Site Lease may be executed in as many counterparts as
the parties deem necessary, each of which shall be deemed an original, and all
of such counterparts together shall constitute one and the same instrument. This
Master Lease and any Site Lease may be executed in triplicate counterparts, each
of which shall be deemed an original.

      (h) Language. This Master Lease is executed and each Site Lease will be
executed in the English language; provided, however, that the parties hereto
hereby irrevocably agree and accept that the Spanish translation of this
Agreement attached hereto as Exhibit C, is a true, accurate and complete
translation of this Agreement that shall be used in the event that any party
hereto brings a legal action or proceeding with respect to this Agreement and
the parties hereto hereby waive any right to challenge the validity,
truthfulness, accuracy or completeness of such Spanish translation.

      17. TOWER MARKING AND LIGHTING REQUIREMENTS.

      For each Site, MATC shall be responsible for compliance with all marking
and lighting requirements under applicable laws and regulations in Mexico,
provided that if the requirement for compliance results from Lessee's
Improvements and Equipment, Lessee shall pay for the reasonable costs and
expenses therefor.

      18. INDEMNITY.

      (a) Each party hereto ("INDEMNIFYING PARTY") agrees to compensate the
other party for damages and to defend, indemnify and to hold the other party
harmless from all claims (including reasonable attorneys' fees, costs and
expenses of defending against such claims) incurred and arising from the
negligent acts or omissions of the Indemnifying Party or its agents, employees,
engineers, contractors, subcontractors, or invitees in or about the Premises or
arising from the

                                       24

<PAGE>

Indemnifying Party's default pursuant to this Master Lease or the applicable
Site Lease. Except as otherwise specifically provided herein to the contrary, it
is understood and agreed that all property kept, installed, stored, or
maintained in or upon the Premises by Lessee shall be so installed, kept,
stored, or maintained at Lessee's risk. Neither party hereto shall be
responsible for any loss or damage to equipment owned by the other party which
might result from tornadoes, lightning, wind storms, hail, flying debris, or
other acts of God (caso fortuito o fuerza mayor). The indemnities described in
this Section shall survive termination of this Master Lease or the applicable
Site Lease.

      (b) Notwithstanding any provision of this Master Lease to the contrary
(other than Section 5 hereof), each party hereby waives the right to recover
consequential (including lost profits), punitive, exemplary and similar damages
and the multiplied portion of damages to the extent provided under applicable
law, except to the extent such damages are suffered by such party in connection
with an action initiated by a third party in which case the damages paid to such
third party shall be deemed compensatory damages.

      (c) Notwithstanding anything to the contrary contained in this Master
Lease, no party may be granted indemnity under this Master Lease if it has
already received indemnity for the same claim under the Purchase Agreement.

      19. HAZARDOUS SUBSTANCES.

      Lessee agrees that it will not use, generate, store or dispose of any
hazardous material on, under, about or within the Sites in violation of any law
or regulation. MATC represents, warrants and agrees (i) that neither MATC nor,
to MATC's knowledge, any third party has used, generated, stored or disposed of,
or permitted the use, generation, storage or disposal of, any hazardous material
on, under, about or within the Sites in violation of any law of regulation,
unless otherwise disclosed in the applicable Site Lease and (ii) that MATC will
not generate, store or dispose of any hazardous material on, under, about or
within the Sites in violation of any law or regulation. MATC and Lessee each
agree to defend, indemnify and hold harmless the other party and the other
party's partners, affiliates, agents and employees against any and all losses,
liabilities, claims and/or costs (including reasonable attorneys' fees and
costs) arising from any breach of any representation, warranty or agreement
contained in this Section 19. As used in this Section 19, "HAZARDOUS MATERIAL"
shall mean petroleum or any petroleum product, asbestos, and/or any substance,
chemical or waste that is identified as hazardous, toxic or dangerous in any
applicable federal, state or local law or regulation. This Section shall survive
the termination of this Master Lease.

      20. REPLACEMENT OR RECONSTRUCTION OF TOWER BY MATC.

      Notwithstanding anything to the contrary contained herein, Lessee
acknowledges and agrees that MATC reserves the right to replace or rebuild an
existing structure or the top of any structure upon no less than ten (10) days
prior written notice to Lessee, provided, however, that in the event of such
replacement, MATC shall provide Lessee with suitable space at the Site during
the construction period to permit the continued operation of Lessee's
Improvements and Equipment and MATC shall be solely responsible for the costs
associated with removing and re-

                                       25

<PAGE>

installing the Lessee's Improvements and Equipment on the replacement structure.
MATC also expressly reserves the right to erect one or more Towers on the Site,
subject to MATC's obligations to Lessee pursuant to Section 8 of this Master
Lease. In no event shall Lessee's Base Rent be abated in any manner during any
period of construction of the Tower or candelabra so long as Lessee is capable
of continuing to operate its equipment from a temporary location on the Site.
Lessee acknowledges and agrees that it will reasonably cooperate with MATC in
any actions, filings, or permits which may be required for MATC to exercise its
rights under this Section 20. In the event that the replacement space provided
to Lessee fails to meet Lessee's RF standards, Lessee shall reserve the right to
terminate the applicable Site Lease upon thirty (30) days notice to MATC without
any further obligation of either party to the other hereunder.

      21. CONFIDENTIALITY.

      The parties agree to hold the economic terms and conditions of this
Agreement in strict confidence, and shall bind its employees, affiliates,
advisors, representatives and agents to keep such economic terms in strict
confidence, and not to make any disclosure with respect thereto, publicly or
privately, other than as is jointly agreed to by the parties or as is required
by applicable law (of any applicable country), including the rules and
regulations of the Mexican National Banking and Securities Commission, the U.S.
Securities and Exchange Commission, and the stock exchange rules or regulations.
If a public statement by either party is determined to be required by law or
stock exchange rules or regulations, the other party shall have the right to
review and comment on such statement prior to its release to the extent
practicable. Except as otherwise provided above, without the prior written
consent of the other party, no party shall at any time disclose any such
economic terms to any third party not bound by the confidential duty. The
provisions contained herein shall survive termination of this Agreement and
shall remain in full force and effect for a term of five (5) years after
termination of this Agreement.

      22. DISPUTE RESOLUTION.

      SECTION 22.1 AGREEMENT TO ARBITRATE. Any and all claims, counterclaims,
demands, causes of action, disputes, controversies, and other matters in
question arising out of or relating to this Agreement, or the alleged breach
hereof, or in any way relating to the subject matter of this Agreement or the
relationship between the Parties created by this Agreement (all of which are
referred to herein as "CLAIMS"), between two or more parties (each a "DISPUTING
PARTY") shall be resolved by binding arbitration, regardless of whether such
Claims (a) allegedly are extra-contractual in nature, (b) sound in contract,
tort, or otherwise, (c) are provided for by statute or otherwise, or (d) seek
damages or any other relief; provided, however, that each Party expressly waives
any right to any form of damages in excess of compensatory damages, and agrees
not to seek such damages in any forum, as a result of any dispute, controversy
or claim arising out of, relating to or in connection with this Agreement,
including, without limitation, any dispute regarding its validity or
termination, or the performance or breach thereof, and each party further agrees
that the arbitrators are divested of, and will not have, jurisdiction or the
authority to award any form of damages in excess of compensatory damages.
Without limiting the authority conferred on the arbitrators by this Agreement
and the ICC Rules, the arbitrators shall have the authority to award specific
performance. No Claim shall be submitted to arbitration until sixty (60) days
have passed (without mutual agreement having been reached) following the first

                                       26

<PAGE>

written notice from a Disputing Party to the other Disputing Parties that sets
forth the subject matter of the Claim and that states that it is being given
pursuant to this Section 22.1. Each Disputing Party shall, if requested by
another Disputing Party, select and appoint a senior executive (not concerned
with the day-to-day performance of the appointor's obligations under this
Agreement) to serve on a panel seeking to reach mutual agreement with respect to
the applicable Claim. Each such appointment shall be made by the giving of
notice by the appointor to the other Disputing Parties within ten (10) Business
Days of the request for the appointment. The appointees shall meet and shall
endeavor to reach such mutual agreement as soon as practicable.

      SECTION 22.2 APPOINTMENT OF ARBITRATORS. If no such mutual agreement has
been reached within such sixty (60) day period, then any Disputing Party may
refer the claim to arbitration under the following provisions:

      (a) To refer a claim to arbitration, a Disputing Party must provide notice
to the ICC and the other Disputing Parties stating (i) a general description of
the Claim and (ii) that the Claim is being referred to arbitration under this
Section 22.

      (b) The arbitration panel shall consist of three neutral arbitrators. Each
Disputing Party shall appoint one arbitrator, obtain its appointee's acceptance
of such appointment, and deliver written notification of such appointment and
acceptance to the other Disputing Party within thirty (30) days after delivery
of the notice described in Section 22.2(a) hereof. In the event a Disputing
Party fails to appoint an arbitrator or deliver notification of such appointment
to the other Disputing Party within this time period, upon request of either
Disputing Party, such arbitrator shall instead be appointed by the ICC within
thirty (30) days of receiving such request. The two arbitrators appointed in
accordance with the above provisions shall appoint the third arbitrator, obtain
the appointee's acceptance of such appointment and notify the Disputing Parties
in writing of such appointment and acceptance within thirty (30) days of their
appointment. If the first two appointed arbitrators fail to appoint a third
arbitrator or notify the Disputing Parties of that appointment within this time
period, then, upon request of either Disputing Party, the third arbitrator shall
be appointed by the ICC within thirty (30) days of receiving such request. The
third arbitrator shall serve as chairman of the arbitration tribunal. All
Arbitrators appointed pursuant to this Section 22.2 shall be attorneys licensed
to practice law in Mexico.

      SECTION 22.3 AUTHORITY OF THE ARBITRATORS. The validity, construction, and
interpretation of this agreement to arbitrate, and all procedural aspects of the
arbitration conducted pursuant to this agreement to arbitrate, including, but
not limited to, the determination of the issues that are subject to arbitration
(i.e., arbitrability), the scope of the arbitrable issues, allegations of "fraud
in the inducement" to enter into this agreement to arbitrate, allegations of
waiver, delay or other defenses to arbitrability, the appropriateness of summary
judgment and the rules governing the conduct of the arbitration (including the
time for filing an answer, the time for the filing of counterclaims, the times
for amending the pleadings, the specificity of the pleadings, the extent and
scope of discovery, the issuance of subpoenas, the times for the designation of
experts, whether the arbitration is to be stayed pending resolution of related
litigation involving third parties not bound by this agreement to arbitrate, the
receipt of evidence, and the like) shall be decided by the arbitrators. The
arbitrators shall have the authority to assess

                                       27

<PAGE>

the costs and expenses of the arbitration proceeding (including the arbitrators'
fees and expenses) against one or more of the Disputing Parties in whatever
manner or allocation the arbitrators deem appropriate, provided that each
Disputing Party shall bear its own attorneys' fees, and the arbitrators shall
have no authority to award attorneys' fees.

      SECTION 22.4 PLACE OF ARBITRATION. The arbitration proceeding shall be
conducted in Mexico City, Mexico.

      SECTION 22.5 CONDUCT OF THE ARBITRATION. It is the intent of the Parties
that, barring extraordinary circumstances, the arbitration proceedings shall be
concluded within one hundred eighty (180) days from the date the arbitrators are
appointed. The Parties may agree to extend this time limit or the arbitrators
may do so in their discretion if they determine that the interest of justice so
requires. The arbitrators shall use their best efforts to issue the Award within
sixty (60) days after closure of the proceedings. Failure to adhere to these
time limits shall not be a basis for challenging the award. The arbitration
proceedings and the award or decision ("AWARD") of the arbitrators shall be in
English. Notwithstanding the foregoing, either Disputing Party may submit
testimony or documentary evidence in the Spanish language, provided that the
Disputing Party submitting such evidence, at its own cost, also furnishes to the
other party a translation into the English language.

      SECTION 22.6 ICC RULES. The arbitration shall be conducted under the ICC
Rules, except as they may be modified in this Section 22 or by agreement of the
Parties.

      SECTION 22.7 PAYMENT OF AWARD. Each Disputing Party against which the
arbitrators' Award assesses a monetary obligation shall pay that obligation on
or before the 30th day following the Award or such other date as the Award may
provide, which Award shall be payable in cash in dollars unless the Award
specifies a different currency.

      SECTION 22.8 FINALITY OF THE ARBITRATORS' AWARD. The arbitrators' Award
shall, as between the Disputing Parties and those in privity with them, be final
and entitled to all of the protections and benefits of a final judgment, e.g.,
res judicata (claim preclusion) and collateral estoppel (issue preclusion), as
to all Claims, including compulsory counterclaims, that were or could have been
presented to the arbitrators. The arbitrators' Award shall not be reviewable by
or appealable to any court.

      SECTION 22.9 USE OF THE COURTS. It is the intent of the Parties that the
arbitration proceeding shall be conducted expeditiously, without initial
recourse to the courts and without interlocutory appeals of the arbitrators'
decisions to the courts. However, by agreeing to arbitration, the Parties do not
intend to deprive any court with jurisdiction of its ability to issue a
preliminary injunction, attachment or other form of provisional remedy in aid of
the arbitration and a request for such provisional remedies by a Disputing Party
to a court shall not be deemed a waiver of the agreement to arbitrate contained
in this Section 22. Any court order compelling arbitration shall require that
the arbitration proceedings take place in Mexico City, Mexico as specified
above. The Disputing Parties may apply to any court having jurisdiction for
orders requiring witnesses to obey subpoenas issued by the arbitrators.
Moreover, any and all of the arbitrators' orders and decisions may be enforced
if necessary by any court having jurisdiction.

                                       28

<PAGE>

The arbitrators' Award may be confirmed in, and judgment upon the Award entered
by, any court having jurisdiction.

      SECTION 22.10 CONFIDENTIALITY. Except as may be required by applicable law
or court order, the Disputing Parties shall maintain confidentiality as to all
aspects of the arbitration, including its existence and results, except that
nothing herein shall prevent any Disputing Party from disclosing information
regarding the arbitration for purposes of enforcing the Award or in any court
proceeding involving the Disputing Parties. The Parties further agree to obtain
the arbitrators' agreement to preserve the confidentiality of the arbitration.
However, a violation of this covenant shall not affect the enforceability of
this agreement to arbitrate or of the arbitrators' Award.

      SECTION 22.11 ARBITRATION PROVISION ENFORCEABLE. A Disputing Party's
breach of this Agreement shall not affect this agreement to arbitrate. Moreover,
the Parties' obligations under this arbitration provision are enforceable even
after this Agreement has terminated. The invalidity or unenforceability of any
provision of this agreement to arbitrate shall not affect the validity or
enforceability of the Disputing Parties' obligation to submit their Claims to
binding arbitration or the other provisions of this agreement to arbitrate.

      SECTION 22.12 MINOR DISPUTE RESOLUTION.

      (a) In the event there is a Claim between the Parties involving an
aggregate amount of one million dollars (US$1,000,000) or less (a "MINOR CLAIM")
that has not been resolved by mutual agreement of the Parties pursuant to
Section 22.1, then the Minor Claim shall be resolved by binding arbitration in
accordance with this Section 22.12.

      (b) The arbitration shall be conducted under the Rules of Arbitration of
the Arbitration Center of Mexico ("CAM") as in force at the time such
arbitration is commenced (the "CAM ARBITRATION RULES").

      (c) The arbitration proceeding shall be conducted in Mexico City, Mexico,
or any other place mutually agreed to by the Parties, and the arbitration
proceedings shall be conducted in the English language.

      (d) The award rendered by the arbitrators shall be in writing, in the
English language, and shall set forth in reasonable detail the facts of the
Minor Claim and the reasons for the arbitrators' decision, and shall apportion
the costs of the arbitration.

      (e) Each Disputing Party against which the arbitrators' award assesses a
monetary obligation shall pay that obligation on or before the 30th day
following the award or such other date as the award may provide, which award
shall be payable in cash in U.S. dollars unless the award specifies a different
currency.

      (f) The arbitrators' award shall, as between the Disputing Parties and
those in privity with them, be final and entitled to all of the protections and
benefits of a final judgment, e.g., res judicata (claim preclusion) and
collateral estoppel (issue preclusion), as to all Minor Claims, including
compulsory counterclaims, that were or could have been presented to the
arbitrators.

                                       29

<PAGE>

The arbitrators' award shall not be reviewable by or appealable to any court or
subject to further arbitration pursuant to Sections 22.1 through 22.11.

      (g) It is the intent of the Parties that the arbitration proceeding shall
be conducted expeditiously, without initial recourse to the courts and without
interlocutory appeals of the arbitrators' decisions to the courts. However, by
agreeing to arbitration, the Parties do not intend to deprive any court with
jurisdiction of its ability to issue a preliminary injunction, attachment or
other form of provisional remedy in aid of the arbitration and a request for
such provisional remedies by a Disputing Party to a court shall not be deemed a
waiver of the agreement to arbitrate contained in this Section 22. Any court
order compelling arbitration shall require that the arbitration proceedings take
place in Mexico City, Mexico as specified above. The Disputing Parties may apply
to any court having jurisdiction for orders requiring witnesses to obey
subpoenas issued by the arbitrators. Moreover, any and all of the arbitrators'
orders and decisions may be enforced if necessary by any court having
jurisdiction. The arbitrators' award may be confirmed in, and judgment upon the
award entered by, any court having jurisdiction.

      (h) Except as may be required by applicable law or court order, the
Disputing Parties shall maintain confidentiality as to all aspects of the
arbitration, including its existence and results, except that nothing herein
shall prevent any Disputing Party from disclosing information regarding the
arbitration for purposes of enforcing the award or in any court proceeding
involving the Disputing Parties. The Parties further agree to obtain the
arbitrators' agreement to preserve the confidentiality of the arbitration.
However, a violation of this covenant shall not affect the enforceability of
this agreement to arbitrate or of the arbitrators' award.

      (i) A Disputing Party's breach of this Agreement shall not affect this
agreement to arbitrate. Moreover, the Parties' obligations under this
arbitration provision are enforceable even after this Agreement has terminated.
The invalidity or unenforceability of any provision of this agreement to
arbitrate shall not affect the validity or enforceability of the Disputing
Parties' obligation to submit their Claims to binding arbitration or the other
provisions of this agreement to arbitrate.

      23. JOINT OBLIGATION.

      By execution of this Master Lease, Grupo Iusacell Celular hereby agrees to
be jointly and severally liable for all of the obligations of Lessee under this
Master Lease with respect to any Site purchased under the 2001 Purchase
Agreement, and Grupo Iusacell agrees to be jointly and severally liable for all
the obligations of Lessee under this Master Lease with respect to Sites
purchased under the 2003 Purchase Agreement. In terms of Article 1987, 1988 and
other related articles of the Federal Civil Code of Mexico and related articles
of other civil codes of Mexico.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       30

<PAGE>

      IN WITNESS WHEREOF, the parties have executed this Master Lease as of the
date first above written.

      IUSACELL ARRENDADORA, S.A. DE C.V.

                                          By ___________________________________
                                             Name: Jose  Ignacio Morales Elcoro
                                             Title: Attorney-in-Fact

                                          By ___________________________________
                                             Name: Jorge Narvaez Mazzini
                                             Title: Attorney-in-Fact

      GRUPO IUSACELL, S.A. DE C.V.,
      AS JOINT OBLIGOR

                                          By ___________________________________
                                             Name: Jose  Ignacio Morales Elcoro
                                             Title: Attorney-in-Fact

                                          By ___________________________________
                                             Name: Jorge Narvaez Mazzini
                                             Title: Attorney-in-Fact

      GRUPO IUSACELL CELULAR, S.A. DE C.V.,
      AS JOINT OBLIGOR

                                          By ___________________________________
                                             Name: Jose  Ignacio Morales Elcoro
                                             Title: Attorney-in-Fact

                                          By ___________________________________
                                             Name: Jorge Narvaez Mazzini
                                             Title: Attorney-in-Fact

                           Master Lease Signature Page
                                       S-1

<PAGE>

                                             MATC CELULAR, S. DE R.L. DE C.V.

                                             By: _______________________________
                                             Name: Lawrence Gleason
                                             Title:   Attorney-in-Fact

                                             MATC DIGITAL, S. DE R.L. DE C.V.

                                             By: _______________________________
                                             Name: Lawrence Gleason
                                             Title: Attorney-in-Fact

                           Master Lease Signature Page
                                       S-2

<PAGE>

                                    EXHIBIT A

                                  DEFINED TERMS

      "ADDITIONAL RENT" has the meaning ascribed to such term in Section 5(c) of
this Agreement.

      "AFFILIATES" will mean, with respect to the party, person or entity in
question, any entity or person that owns or controls, is owned or controlled by
or is under common control with such party, person or entity. For the purposes
of this definition, control of any party, person or entity means ownership,
directly or indirectly, of (a) 50% or more of the voting stock, if a
corporation, and ownership of 50% or more of the equity or beneficial interest
in any other party, person or entity, or (b) 45% or more of the voting stock or
the equity or beneficial interest in such party, person or entity and management
control of such party, person or entity. The general partner of any partnership
will be deemed to control such partnership. Notwithstanding anything to the
contrary contained in this Agreement, neither (i) Unefon, S.A. de C.V. (ii) TV
Azteca, S.A. de C.V., (iii) Movil Access, S.A. de C.V., (iv) Biper, S.A. de C.V.
nor (v) Ricardo Salinas Pliego and other entities controlled by the Salinas
Group other than Grupo Iusacell and its subsidiaries shall be considered
Affiliates of Grupo Iusacell.

      "AGREEMENT" means this Master Lease together with its exhibits.

      "AMENDED AND RESTATED MASTER LEASE AGREEMENT" has the meaning assigned in
the recitals of this Agreement.

      "AVAILABLE SPACE" has the meaning ascribed to such term in Section 7(c) of
this Agreement.

      "AWARD" has the meaning ascribed to such term in Section 22.5 of this
Agreement.

      "BASE LOADING" has the meaning ascribed to such term in Section 7(a) of
this Agreement.

      "BASE RENT" has the meaning ascribed to such term in Section 5(b) of this
Agreement.

      "BUILD-TO-SUIT AGREEMENT" means that certain Build-to-Suit and Site
Development Agreement attached as Exhibit G hereto.

      "BUSINESS DAY" means any day other than a Saturday, Sunday or holiday of
the federal government of the United States of America or the United Mexican
States.

      "CAM" has the meaning ascribed to such term in Section 22.12(b) of this
Agreement.

      "CAM ARBITRATION RULES" has the meaning ascribed to such term in Section
22.12(b) of this Agreement.

      "CHASE" has the meaning ascribed to such term in Section 13(c) of this
Agreement.

                                      A-1

<PAGE>

      "CHASE LENDERS" has the meaning ascribed to such term in Section 13(c) of
this Agreement.

      "CLAIMS" has the meaning ascribed to such term in Section 22.1 of this
Agreement.

      "CLOSING" means the consummation of the transfer of the Sites and other
transactions contemplated by the Purchase Agreement, which shall occur in
multiple closings (individually, a "CLOSING," and collectively, the "CLOSINGS").

      "CLOSING DATE" means the date of the applicable Closing.

      "COMMENCEMENT DATE" means the date on which a Site is conveyed to MATC
pursuant to the Purchase Agreements.

      "DISPUTING PARTY" has the meaning ascribed to such term in Section 22.1.
of this Agreement.

      "EFFECTIVE DATE" has the meaning ascribed to such term in Section 4(a) of
this Agreement.

      "EXCHANGE TOWER" has the meaning ascribed to such term in Section 2.5 of
the Purchase Agreement.

      "FINANCING SECURED PARTIES" has the meaning ascribed to such term in
Section 13(c) of this Agreement.

      "FIRST AMENDED MORTGAGE" has the meaning ascribed to such term in Section
13(c) of this Agreement.

      "FIRST RENEWAL TERM" has the meaning ascribed to such term in Section 4(b)
of this Agreement.

      "FIRST UNION" has the meaning ascribed to such term in Section 13(c) of
this Agreement.

      "FORCE MAJEURE" means those events constituting excuse from timely
performance by MATC or Lessee of any of their respective duties and/or
obligations required under this Agreement, as described in Section 15(b).

      "GOVERNMENTAL AUTHORITY" means any federal, state, county or municipal
governmental authority, including all executive, legislative, judicial and
administrative bodies thereof.

      "GOVERNMENTAL REQUIREMENTS" means all federal, state, county or municipal
laws, ordinances, and regulations and all orders and decrees of all Governmental
Authorities.

      "GRUPO IUSACELL" has the meaning assigned in the preamble of this
Agreement.

      "GRUPO IUSACELL CELULAR" has the meaning assigned in the preamble of this
Agreement.

                                      A-2

<PAGE>

      "HAZARDOUS MATERIAL" has the meaning ascribed to such term in Section 19
of this Agreement.

      "ICC" means the Court of Arbitration of the International Chamber of
Commerce.

      "ICC RULES" means the Rules of Arbitration of the International Chamber of
Commerce.

      "INDEMNIFYING PARTY" has the meaning ascribed to such term in Section
18(a) of this Agreement.

      "INITIAL TERM" has the meaning ascribed to such term in Section 4(b) of
this Agreement.

      "LABOR OBLIGATIONS" has the meaning ascribed to such term in Section 14(b)
of this Agreement.

      "LESSEE" has the meaning ascribed to such term in the preamble of this
Agreement.

      "LESSEE'S IMPROVEMENTS AND EQUIPMENT" has the same meaning ascribed to the
term Telecommunications Equipment as defined in the Purchase Agreement.

      "LESSEE MORTGAGEES" has the meaning ascribed to such term in Section 13(c)
of this Agreement.

      "LOSSES" has the meaning ascribed to such term in Section 14(b) of this
Agreement.

      "MASTER LEASE" has the meaning ascribed to such term in the preamble of
this Agreement.

      "MATC" means MATC Celular with respect to any Site purchased pursuant to
the 2001 Purchase Agreement or MATC Digital with respect to any Site purchased
pursuant to the 2003 Purchase Agreement, as applicable.

      "MATC CELULAR" has the meaning ascribed to such term in the preamble of
this Agreement.

      "MATC'S LENDERS" has the meaning ascribed to such term in Section 13(d) of
this Agreement.

      "MAXIMUM EQUIPMENT" has the meaning ascribed to such term in Section 7(a)
of this Agreement.

      "MAXIMUM MICROWAVE ANTENNAS" has the meaning ascribed to such term in
Section 7(a) of this Agreement.

      "MEXICO" has the meaning ascribed to such term in Section 16(e) of this
Agreement.

      "MINOR CLAIM" shall have the meaning ascribed to such term in Section
22.12.

                                      A-3

<PAGE>

      "MLA FOR BTS SITES" shall mean the Master Lease Agreement regarding Build
to Suit Sites attached as Exhibit F hereto.

      "NEW EQUIPMENT" has the meaning ascribed to such term in Section 7(c) of
this Agreement.

      "NOTICE OF OFFER" has the meaning ascribed to such term in Section 7(g) of
this Agreement.

      "ORIGINAL MASTER LEASE AGREEMENT" has the meaning ascribed to such term in
the recitals of this Amendment.

      "OTHER TENANT" has the meaning ascribed to such term in Section 6(a) of
this Agreement.

      "PARTIES" has the meaning assigned in the preamble of this Amendment.

      "PER CAPITA SHARE" has the meaning ascribed to such term in Section 5(c)
of this Agreement.

      "PERMITS" means any and all certificates, licenses, permits,
authorizations, consents, special use permits, environmental studies, and other
analyses and approvals required or issued by the applicable governmental
authorities having jurisdiction in such matters required to be obtained, issued,
granted or received for the construction and use of any New Equipment.

      "PORTATEL MORTGAGE" has the meaning ascribed to such term in Section 13(c)
of this Agreement.

      "POTENTIAL TENANT" has the meaning ascribed to such term in Section 7(g)
of this Agreement.

      "POTENTIAL TENANT SPACE" has the meaning ascribed to such term in Section
7(g) of this Agreement.

      "PREMISES" shall have the meaning ascribed to such term in Section III(c)
of the Recitals to this Agreement.

      "PRIME LEASE" has the meaning ascribed to such term in Section 1(g) of
this Agreement.

      "PURCHASE AGREEMENT" has the meaning ascribed to such term in Section
III(b) of the Recitals to this Agreement.

      "PUT TOWER" has the meaning ascribed to such term in Section 2.5 of the
Purchase Agreement.

      "QUARTERLY STATEMENT" has the meaning ascribed to this term in Section
6(b) of this Agreement.

      "REGION" has the meaning ascribed to such term in Section 13(a) of this
Agreement.

                                      A-4

<PAGE>

      "RENEWAL TERM" has the meaning ascribed to such term in Section 4(b) of
this Agreement.

      "SECOND AMENDED MORTGAGE" has the meaning ascribed to such term in Section
13(c) of this Agreement.

      "SECOND RENEWAL TERM" has the meaning ascribed to such term in Section
4(b) of this Agreement.

      "SITES" means the 2001 Purchased Sites and the 2003 Purchased Sites,
collectively.

      "SITE LEASE" means a Site Lease between Lessee and MATC relating to
Lessee's use of the Premises at a Site, in the form attached as Exhibit B
hereto.

      "TERM" means the Initial Term and any Renewal Terms entered into pursuant
to Section 4(b) of this Agreement.

      "TERMINATION PERIOD" has the meaning ascribed to such term in Section
14(c) of this Agreement.

      "TOWER" means a radio tower structure.

      "TOWER SITE PERMITS " means any and all certificates, licenses, building,
special use and other permits, authorizations, consents, and other approvals
issued by the applicable Governmental Authority having jurisdiction in such
matters required to be obtained, issued, granted, received and/or maintained in
connection with any Sites under this Agreement, including, without limitation,
construction permits and permits issued by the applicable aviation authorities.

      "2001 PURCHASE AGREEMENT" has the meaning ascribed to such term in Section
IV(d) to the Recitals of this Agreement.

      "2003 PURCHASE AGREEMENT" has the meaning ascribed to such term in Section
IV(d) to the Recitals to this Agreement.

      "2001 PURCHASED SITES" has the meaning ascribed to such term in Section
IV(c) of the Recitals of this Agreement.

      "2003 PURCHASED SITES" has the meaning ascribed to such term in Section
IV(c) to the Recitals of this Agreement.

                                      A-5

<PAGE>

                                    EXHIBIT B
                               FORM OF SITE LEASE
       [This is intended by the parties hereto to be a sample, which shall
 be modified by the mutual agreement of the parties hereto, from time to time]

ATC No.

                            CONTRATO DE ARRENDAMIENTO

FERNANDO JOSE CABRERA GARCIA Y
JORGE NARVAEZ MAZZINI
REPRESENTANTES LEGALES
IUSACELL ARRENDADORA, S.A. DE C.V.

EL PRESENTE CONTRATO DE ARRENDAMIENTO LO FIRMA MATC CELULAR, S. DE R.L. DE C.V.
("MATC CELULAR") EN LOS TERMINOS DEL NUEVO CONTRATO MAESTRO DE ARRENDAMIENTO DE
FECHA 23 DE FEBRERO DEL 2001, (MODIFICADO Y REEXPRESADO CON FECHA ____ DE
DICIEMBRE DE 2003, EN LO SUCESIVO EL "CONTRATO MAESTRO DE ARRENDAMIENTO"),
CELEBRADO POR "MATC CELULAR" Y IUSACELL ARRENDADORA, S.A. DE C.V. ("EL
ARRENDATARIO").

LOS TERMINOS QUE NO SE ENCUENTREN EXPRESAMENTE DEFINIDOS EN EL PRESENTE
INSTRUMENTO TENDRAN EL SIGNIFICADO QUE SE LES ASIGNA A LOS MISMOS EN EL
"CONTRATO MAESTRO DE ARRENDAMIENTO".

QUE CON FECHA 01 DE SEPTIEMBRE DE 2000, [EMPRESA DE IUSACELL QUE TIENE CELEBRADO
EL CONTRATO DE ARRENDAMIENTO], CELEBRO UN CONTRATO DE ARRENDAMIENTO CON
[__________________], SOBRE EL INMUEBLE UBICADO EN [______________________].

Informacion del Sitio.

NOMBRE DEL SITIO: [____________]

Coordenadas.

LATITUD:    [____________]
LONGITUD: [_____________]

El Sitio es:

   [ ]      SITIO EXISTENTE DE MATC

   [ ]      CONSTRUIDO BAJO ESPECIFICACIONES "BUILT TO SUIT AGREEMENT"

    X       SITIO ADQUIRIDO EN TERMINOS DEL CONTRATO DE COMPRAVENTA DE FECHA 23
   DE FEBRERO DE 2001, MODIFICADO Y REEXPRESADO CON FECHA [___] DE DICIEMBRE DE
   2003.

Informacion de la Torre.

ALTURA DE LA TORRE: [___] MTS
TIPO DE LA TORRE:

                                      B-1

<PAGE>

      -     AUTOSOPORTADA
      X     ARRIOSTRADA
      -     MONOPOLO
      -     OTRO, ESPECIFICAR: N/A

Renta y Plazo.

FECHA DE INICIO DEL CONTRATO DE ARRENDAMIENTO: [__________________]
POR ESPACIO EN TORRE: $[________] USD. MENSUALES
POR ARRENDAMIENTO DE ESPACIO $[_________]  M/N [_______]
PLAZO: 10 ANOS (MAS CUALESQUIER RENOVACIONES) SUJETO A LAS DISPOSICIONES
SENALADAS EN LA SECCION 1, INCISO G), Y A LOS DEMAS TERMINOS Y CONDICIONES DEL
"CONTRATO MAESTRO DE ARRENDAMIENTO"
AREA ARRENDADA: [_________]
TERRENO O AZOTEA: [_________]

LAS DISPOSICIONES DE LA SECCION 4 DEL "CONTRATO MAESTRO DE ARRENDAMIENTO" SERAN
APLICABLES RESPECTO AL PLAZO DE VIGENCIA (INCLUYENDO CUALESQUIER RENOVACIONES).
LAS DISPOSICIONES DE LA SECCION 5 DEL "CONTRATO MAESTRO DE ARRENDAMIENTO" SERAN
APLICABLES CON RELACION A INCREMENTOS EN LA RENTA.

Ubicacion / Identificacion del Espacio

ALTURA DEL CENTRO DE RADIACION (ANTENAS CELULARES):

      -     ALFA: [3 METROS            4 ANTENAS]
      -     BETA: [6 METROS            NA ANTENAS]
      -     GAMA:[18 METROS   NA ANTENAS]

Informacion sobre las antenas celulares.

FRECUENCIA RX: [824 - 849 MHZ]
NUMERO DE ANTENAS: [4]
FRECUENCIA TX: [869  - 894 MHZ]

TIPO DE ANTENA:
            [ ]  OMNIDIRECCIONAL
            [ ]  DIRECCIONAL
            [ ]  OTRO, ESPECIFICAR _______________

<TABLE>
<CAPTION>
TIPO                          MODELO                               DIAMETRO DEL CABLE
----                         -------                               ------------------
<S>                          <C>                                   <C>
ALFA                         DB498-C                                   1/2 Y 7/8
BETA                         SRL460                                    1/2 Y 7/8
GAMA                         ASPD950                                   1/2 Y 7/8
</TABLE>

EL ESPACIO A SER ARRENDADO PARA LA UBICACION DEL CONTENEDOR DEL EQUIPO DE
TELECOMUNICACIONES DE "EL ARRENDATARIO" SE DESCRIBE EN EL ANEXO B DEL PRESENTE
DOCUMENTO (LAY OUT) DEL SITIO.

                                      B-2

<PAGE>

Equipo de "El Arrendatario" instalado en la Torre:

<TABLE>
<CAPTION>
TIPO DE                 DIAMETRO   PESO  TIPO DE                         FRECUENCIA    ALTURA
-------                 --------  -----  -------                         ----------    ------
ANTENA   MODELO  MARCA    (mts)   (Kgs)   Linea   AZIMUTH      BANDA        (Tx)        (mts)    TIPO MONTAJE  DIRECCION     RENTA
-------  ------  -----  --------  -----  -------  -------      -----     ----------    ------    ------------  ---------     -----
<S>      <C>     <C>    <C>       <C>    <C>      <C>          <C>       <C>           <C>       <C>           <C>           <C>
  NA       NA     NA       NA       NA     NA       NA           NA          NA          NA           NA          NA         $0.00
</TABLE>

Informacion similar a la prevista anteriormente debera ser entregada para cada
uno de los equipos de microondas y equipos de radiolocalizacion (paging)
instalados en el inmueble, segun corresponda.

DIBUJOS DE LA TORRE AS BUILT (EN SU CASO) SE ADJUNTAN AL PRESENTE MARCADOS COMO
ANEXO C.

INFORMACION SOBRE CONDICIONES AMBIENTALES EN LOS TERMINOS DE LA SECCION 19 DEL
"CONTRATO MAESTRO DE ARRENDAMIENTO":
________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

MEDIANTE LA FIRMA DEL PRESENTE CONTRATO DE ARRENDAMIENTO, EL ARRENDATARIO
MANIFIESTA SU CONSENTIMIENTO PARA OBLIGARSE EN LOS TERMINOS DEL CONTRATO MAESTRO
DE ARRENDAMIENTO. CUALQUIERA DE LAS PARTES ESTARA FACULTADA PARA REGISTRAR EL
PRESENTE CONTRATO DE ARRENDAMIENTO Y EL CONTRATO MAESTRO DE ARRENDAMIENTO EN EL
REGISTRO PUBLICO DE LA PROPIEDAD QUE CORRESPONDA A LA UBICACION DEL INMUEBLE
DESCRITA ANTERIORMENTE. EL PRESENTE INSTRUMENTO SE FIRMA EL DIA ___ DEL MES DE
_____________- DEL 2003.

IUSACELL ARRENDADORA, S.A. DE C.V.              MATC DIGITAL, S. DE R.L. DE C.V.

___________________________________      _______________________________________
Lic. Fernando Jose Cabrera Garcia/       Sr. Lawrence Mac Millan Gleason Jr.
Sr. Jorge Narvaez Mazzini

                                    TESTIGOS

                                      B-3

<PAGE>

___________________________________      _______________________________________
   Lic. Zaida Sosa y Avila Osuna               Lic. Alicia Nieto Carrasco

                                      B-4

<PAGE>

                                    EXHIBIT C

                               SPANISH TRANSLATION

                                      C-1

<PAGE>

                                    EXHIBIT D

      ACCESS PROCEDURES

     [This is intended by the parties hereto to be a sample, which shall be
   modified by the mutual agreement of the parties hereto, from time to time]

1.    So long as the work to be performed at the Site is ground-based only,
Lessee shall have the right to enter the Site at anytime during the Term,
without notice to MATC, in accordance with Section 7(f).

2.    Except for emergency situations, in the event that Lessee or any of its
employees, representatives, agents, contractors, or subcontractors enters the
Site to perform any form of maintenance, repair, installation, or inspection of
any equipment located on the tower structure, Lessee must contact MATC no less
than seven (7) days prior to such visit as follows:

      a.    Call and personally speak with the Director of Operations at
            55-5-240-2000

      b.    Fax a notification of the type of work to be performed, date and
            time of intended visit to the Director of Operations at fax number
            55-5-240-2026.

3.    In the event of an emergency situation in which Lessee or any of its
employees, representatives, agents, contractors, or subcontractors needs to
enter the Site to perform emergency repairs, to the extent possible, Lessee
shall attempt to contact the Director of Operations at 55-5-240-2000 by
telephone or shall leave a message for the Director of Operations prior to their
entrance to the site and may enter such site if they have not had any contact
with the Director of Operations within two hours after leaving such message. In
the event that such contact or message is not possible, Lessee shall personally
speak with the Director of Operations as soon as practicable after the emergency
repairs have been made (but in no event more than twenty-four hours).

                                      D-1

<PAGE>

                                    EXHIBIT E

                               MICROWAVE FORMULAE

Solids:  0.83 X height on tower (ft) X diameter of the dish (ft) = Monthly Fee

Grids:  0.55 X height on tower (ft) X diameter of the dish (ft) = Monthly Fee

All such amounts will remain subject to annual increases in accordance with
Section 5(b) of this Master Lease

                                      E-1

<PAGE>

                                    EXHIBIT F
                                MLA FOR BTS SITES

                [To be in a form agreed upon between the parties]

                                      F-1

<PAGE>

                                    EXHIBIT G

                             BUILD TO SUIT AGREEMENT

                [To be in a form agreed upon between the parties]

                                      G-1

<PAGE>

                                   SCHEDULE 1

                               LIST OF 2001 SITES

<TABLE>
<CAPTION>
NO.              SITE NAME
<S>         <C>
 1          20 DE NOVIEMBRE
 2          ABASOLO
 3          ACAYUCAN
 4          ACTOPAN REP.
 5          ALAMEDA
 6          ALAMITOS
 7          ALFONSO XIII
 8          ALTAMIRA
 9          ALVARADO
10          ARANDAS
11          ARANDAS 2
12          ATIZAPAN
13          ATIZAPAN 450
14          AZCAPOTZALCO
15          BAJA CALIFORNIA
16          BARRANCA DEL MUERTO
17          BUCARELI
18          BUGAMBILIAS
19          C.U.
20          CABEZA DE JUAREZ
21          CAPU
22          CASETA CUERNAVACA
23          CD MENDOZA
24          CD VICTORIA
25          CD. AZTECA
26          CERRO DE EN MEDIO
27          CERRO GORDO
28          CIRCUITO INTERIOR
29          CIVAC
30          CLAVERIA
31          CODESA
32          CONSCRIPTO
33          COSTITUYENTES
34          COYOACAN
35          COYUTLAN
36          CRUZ BLANCA
37          CRUZ DEL SUR
38          CUAJIMALPA
39          CUAUTITLAN
40          CUAUTLA
41          CUBILETE
42          CUERNAVACA II
43          CUERNAVACA III
44          CUERNAVACA IV
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.                SITE NAME
<S>         <C>
45          CULHUACAN
46          CHAPALA
47          CHAPALITA
48          CHAPULTEPEC
49          CHOLULA
50          CHURUBUSCO
51          DEL VALLE
52          DIVISION DEL NORTE
53          DOCTORES
54          ECATEPEC
55          ECHEGARAY
56          EL ABUELO 1
57          EL ABUELO 2
58          EL ROSAL
59          EL TOREO
60          ERMITA REUB.
61          ESPANA
62          ESTRELLA 1
63          ESTRELLA 2
64          ESTRELLA 3
65          ETLA
66          FERROCARRILES JALAPA II
67          FRAY SERVANDO
68          FUENTES BROTANTES
69          HUAMANTLA
70          HUATULCO
71          HUENTITAN
72          HUESO
73          HUIZACHAL
74          INFONAVIT NORTE
75          INSURGENTES SUR
76          INTERLOMAS
77          IZTACALCO
78          IZTAPALAPA
79          JALAPA
80          JARD. DE LA MONTANA
81          JUCHIUTAN
82          KODAK
83          LA IGUANA
84          LA LOMA
85          LA PALMA 1
86          LA PALMA 2
87          LA PIEDAD
88          LA RAZA
89          LA SALUD
90          LA VILLA
91          LA VIRGEN
92          LAGOS DE MORENO
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.                SITE NAME
<S>         <C>
 93         LAS AGUILAS
 94         LAS CRUCES
 95         LAS CHOAPAS
 96         LECHERIA
 97         LEON MODERNO
 98         LERMA
 99         LOMAS
100         LOMAS DE SANTA FE
101         MEXICO 68
102         MEZQUITAN
103         MIXCOAC
104         MORELOS
105         MTZ DE LA TORRE
106         MVS
107         NAPOLES
108         NAUCALPAN
109         NONOALCO
110         OBSERVATORIO
111         OCOTLAN
112         OCOTLAN OAXACA
113         OCOTLAN TLAXCALA
114         PALACIO DE LOS DEPORTES
115         PENJAMO
116         PILARES
117         PORTALES
118         POTRERO
119         PROVIDENCIA
120         PUEBLA NORTE
121         RIO MAGDALENA
122         ROBLES
123         ROJO GOMEZ
124         SAN ALEJANDRO
125         SAN CAYETANO
126         SAN FRANCISCO DEL RINCON
127         SAN IGNACIO CERRO GORDO
128         SAN JUAN DE LOS LAGOS
129         SAN JUAN DEL RIO
130         SAN LORENZO
131         SAN MARTIN
132         SANTA CLARA
133         SANTA URSULA
134         SANTA URSULA
135         SATELITE
136         SEMINARIO
137         TABACALERA
138         TACUBAYA
139         TANCITARO
140         TAXQUENA
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.               SITE NAME
<S>         <C>
141         TECAMACHALCO
142         TECNOLOGICO
143         TECOMAN
144         TEPALCAPA
145         TEPATITLAN
146         TEXCOCO
147         TEZONTLE
148         TLACOLULA
149         TLAHUAC
150         TLALPAN
151         TLANEPANTLA
152         TOLUCA CENTRO
153         TOLUCA II
154         TONALA
155         TOPILEJO
156         TOREO
157         TRES MARIAS 2
158         TRES MARIAS 3
159         TULA
160         TULANCINGO REP
161         TULYEHUALCO
162         URUAPAN
163         VALLE DE BRAVO
164         VALLEJO
165         VISTA HERMOSA
166         VIVEROS II
167         VOLKSWAGEN
168         XOCHIMILCO
169         ZARAGOZA
170         ZOCALO
171         ACAMBARO
172         AEROPUERTO MANZANILLO
173         APAN (HIDALGO)
174         ATLIXCO
175         BARRANQUITAS
176         CAMPESTRE
177         CEMENTOS
178         CENTRO
179         CENTRO HISTORICO
180         CERRO RABON
181         CUERNAVACA I
182         CHALCO
183         DANUBIO
184         DEL MORAL
185         EL FUERTE
186         EL MIRADOR
187         JURIQUILLA
188         LAS CABRAS
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.                      SITE NAME
<S>         <C>
189         LEGARIA
190         LINDAVISTA
191         MATEHUALA
192         MIXHUCA
193         MONUMENTAL PLANETARIO
194         MUSEO
195         NEZA
196         ORIENTE
197         PACHUCA CENTRO
198         PUEBLA CENTRO
199         PUERTO VALLARTA
200         RANCHO CONTENTO
201         SAN ISIDRO (JALISCO)
202         SAN ISIDRO REPETIDOR (TICUMAN, MOR.)
203         SAN JERONIMO
204         SEVILLA
205         TAPALPA
206         TEMIXCO
207         TEPEJI DEL RIO
208         TEPIC
209         TEQUESQUITENGO
210         TEQUILA TORRE 1
211         TEQUILA TORRE 2
212         TORIELLO GUERRA
213         VALLE GOMEZ
214         XOCHIPALA
215         XOCHIPALA
216         ZAMORA MICHOACAN
217         ZONA INDUSTRIAL
218         ZONA ROSA
219         ABASTOS
220         AHUEHUETE
221         ALAMO
222         ALLENDE
223         ATENTIQUE
224         BARRA DE NAVIDAD
225         CERRO PELON
226         CORDOBA
227         CHICAGO
228         CHIHUAHUA
229         EL CARMEN
230         EL HUIZACHE
231         FRONTERA T1
232         FRONTERA T2
233         FUENTES
234         HUAJUAPAM T1
235         HUAJUAPAM T2
236         LA TIJERA
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.               SITE NAME
<S>         <C>
237         LA VICTORIA
238         LAS AMERICAS
239         LAS TORRES
240         OJUELOS
241         PAPANTLA
242         POCITOS
243         PUERTO VALLARTA
244         SAN LUIS SOYATLAN I
245         SANTA ANITA
246         AGUA DULCE 2
247         AHUEHUETE
248         ATOYAC
249         CIMATARIO S.O.S.
250         CIUDAD VALLES
251         COPILCO
252         COSAMALOAPAN
253         DOLORES HIDALGO
254         EL ROCIO
255         EL TAPATIO
256         GUZMAN, CIUDAD
257         IZUCAR DE MATAMOROS
258         LA ISLA
259         LOMA BONITA
260         MAPACHAPA
261         MARFIL
262         MOROLEON
263         OBRERA I (REUBICAC.)
264         SAHUAYO
265         SAN ANTONIO
266         SAN JUANICO
267         SANTA ROSA
268         TEZIUTLAN (B. VISTA)
269         TLAQUEPAQUE
270         YUVILA
271         AEROPUERTO
272         AEROPUERTO ENSENAD
273         ALDRETE
274         AVIACION CIVIL
275         BENITO JUAREZ
276         BIMBO O LAZARO CARD.
277         BOSQUES II (REUB.)
278         BUROCRATAS
279         CACALOAPAN
280         CARRRET. ESCEN. ACAP
281         CELAYA
282         CIPRES
283         COMERMEX LL
284         EJERCITO I (CRUZ ROJA)
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
NO.              SITE NAME
<S>         <C>
285         EJERCITO IV
286         EL ENCANTO (TECATE)
287         ENCARNACION DE DIAZ
288         FUENTE DE PETROLEOS
289         GRAND MEIGAS ACAP.
290         HIDALGO (R 1)
291         HIDALGO (R 6)
292         HONDA, LA
293         HUMO CHICO
294         IBERO
295         INDEPENDENCIA E.
296         INGLATERRA
297         IXTAPA, REP. AEROP.
298         IXTLAN
299         LAS PINAS
300         LOMAS DE CHAMIZAL
301         LOMAS VERDES
302         LOS PINOS
303         MORELIA CENTRO
304         NORMAL
305         PEDREGAL (NUEVO)
306         PEMEX II
307         PIEDAD CENTRO
308         PINOLILLO
309         POLANCO
310         REFORMA II
311         ROMA
312         SAN FELIPE
313         SANTA MONICA
314         SATELITE II
315         SOLIDARIDAD
316         TAXCO
317         TECAMACHALCO
318         TEQUILA, REP.
319         TEQUISQUIAPAN
320         TULANCINGO
321         XICOTEPEC
</TABLE>

<PAGE>

                                     ANNEX 2

                                      SITES

                         TO BE PROVIDED AS DECIDED UPON.<PAGE>

                                                                    Exhibit 4.17

                                  (Translation)

(The national coat of arms.
Ministry of Communications
and Transport [SECRETARIA DE
COMUNICACIONES Y TRANSPORTES])

                                                UNDER MINISTRY OF COMMUNICATIONS
                                                   AND TECHNOLOGICAL DEVELOPMENT

                           Mexico City, July 17, 1990

Mr. Luis Miguel Nino de Rivera Taracena
Legal Representative
Portatel del Sureste, S. A. de C: V.
Cerrada de las Flores 29, casa 3
Colonia Tlacopac
San Angel
C. P. 01040 Mexico, D. F.

      Since Portatel del Sureste, S. A. de C. V., met all legal, technical and
economic requirements of Articles 8, 12 and 15 of the General Means of
Communication Law [LEY DE VIAS GENERALES DE COMUNICACION], and upon the Minister
of Communications' directions, I enclose the Concession Title issued to Portatel
del Sureste, S. A. de C. V., for the construction, running and turning to
account of the public cellular mobile radiotelephony service [SERVICIO PUBLICO
DE RADIOTELEFONIA MOVIL CON TECNOLOGIA CELULAR] in Southeastern Region 8, which
encompases the states of Chiapas, Tabasco, Yucatan, Campeche and Quintana Roo.

                                  Yours truly,

                        Effective Suffrage. No Reelection
                               The Deputy Minister

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       2

                            (An illegible signature)
                          Carlos Mier y Teran Ordiales

      TRANSLATOR'S NOTE: The Concession Title to which the above official letter
refers reads as follows:

"(The national coat of arms.
Ministry of Communications
and Transport)

                         CELLULAR MOBILE RADIOTELEPHONY
                              SOUTHEASTERN REGION 8
                          [RADIOTELEFONIA MOVIL CELULAR
                                REGION 8 SURESTE]

      The Federal Government, through the Ministry of Communications and
Transport (the `Ministry'), represented by Mr. Andres Caso Lombardo, Minister,
hereby issues this Concession Title to PORTATEL DEL SURESTE, S. A. DE C. V. (the
`Concessionaire'), pursuant to the following background and conditions:

                               B A C K G R O U N D

      I. The 1989-1994 National Development Plan [PLAN NACIONAL DE DESARROLLO]
establishes the importance of modernizing the telecommunications system for the
sake of national development and stresses the need to diversify the Concession
services and to improve their quality and extend their coverage with a greater
private sector participation.

      II. The technological progress achieved in connection with cellular radio
communication switching equipment now allows for a more efficient use of the
radio electric spectrum to

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       3

provide a larger number of users with improved quality radiotelephony services
at a reduced cost.

      III On January 17, 1990, the Concessionaire filed an application with the
Ministry for a concession to set up, run and turn to account a public cellular
mobile radiotelephony service network in Southeastern Region 8.

      IV. Based on Article 15 of the General Means oc Communication Law, the
Ministry processed the Concessionair'es applicatrion and ordered that the same
be published on the Official Gazette of the Federation [DIARIO OFICIAL DE LA
FEDERACION]; the application was so published on April 25 and May 11, 1990, and
on the Region's largest circulation dailies. The objections raised against said
application were dismissed as ungrounded based on the opinion issued by the
General Means of Communication Technical and Consultative Commission [COMISION
TECNICA CONSULTIVA DE VIAS GENERALES DE COMUNICACION].

      V. The Federal Government, through the Ministry and based on the above
background and since Portatel del Sureste, S. A. de C. V., met all legal,
technical and economic requirements, and based on Article 36 of the Organic Law
of the Federal Public Administration [LEY ORGANICA DE LA ADMINISTRACION PUBLICA
FEDERAL]; Articles 1, 2, 3, 8, 14, 15 and other pertinent Articles of the
General Means of Communication Law, and on Article 4 of this Ministry's internal
Regulations, hereby issues

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       4

the following

                               C O N C E S S I O N

      To construct, install, maintain, run and turn to account, for a
twenty-year period, a public cellular mobile radiotelephony service network on
the 825-835/870-880 MHz bands in Southeastern Region 8, which encompasses the
states of Chiapas, Tabasco, Yucatan, Campeche and Quintana Roo.

      The Concessionaire, through the public cellular mobile radiotelephony
service network which is the subject matter of the Concession, must provide the
public mobile radiotelephony services to subscribers by interconnecting to the
basic telephony network granted under concession to Telefonos de Mexico, S. A.
de C. V., and other Ministry-licensed networks.

      The Concessionaire accepts this Concession in the terms of the eight
chapters of this Concession Title, which will become effective on its execution
date.

      Mexico, Federal District, July 17, 1990.

THE MINISTER OF COMMUNIUCATIONS              PORTATEL DEL SURESTE,
AND TRANSPORT                                S. A. DE C. V.

(An illegible signature)                     (An illegible signature)
Andres Caso Lombardo                         Luis Miguel Nino de
                                             Rivera Taracena

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       5

                               C O N D I T I O N S

                   CHAPTER 1. DEFINITIONS AND CONCESSION SCOPE

      1.1. PUBLIC NETWORK TO PROVIDE MOBILE PERSON RADIOLOCATION SERVICES

      The public cellular mobile radiotelephony network to which this Concession
refers (the `Network') is made up by the cellular exchanges, base radio electric
stations, links among such exchanges and stations and such other facilities and
equipment as are directly used to provide voice and data communication
Concession services among Network subscribers by means of channels and radio
electric frequency circuits and to interconnect to the public basic telephony
network whose operation has been awarded to Telefonos de Mexico, S. A. de C. V.,
pursuant to a concession (the `Public Basic Telephony Network') and to other
public telecommunications networks.

      The subscribers' mobile or fixed terminal radio communication equipment is
not a part of the Network.

      The Concessionaire must operate the Network in the `A' cellular group
frequencies made by 333 frequency pairs on the 825-835 MHz/870-880 MHz bands,
with a 30 KHz channel space, as indicated on Exhibit `B' to this Concession.
Said frequency bands may not be modified without the Ministry's prior written
authorization.

      The Concession service area is Southeastern Region 8, which encompasses
the States of Chiapas, Tabasco, Yucatan, Campeche and Quintana Roo.

      1.2. MOBILE CELLULAR RADIOTELEPHONY SERVICE

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       6

      The mobile cellular radiotelephony service to be provided by the
Concessionaire is a final telecommunications service which provides full voice
communication capability among subscribers plus subscriber connection to users
of the Public Basic Telephony Network and other authorized public networks.

      In order to provide the full public radiotelephony service against payment
of specific charges, the Concessionaire will:

      a) Install, maintain and run the Network in order to transmit signals
between the subscribers' radiotelephony terminals and to interconnect them to
the Public Basic Telephony Network and other Ministry-licensed public networks.

      b) Supply, connect and maintain the terminal radiotelephony equipment upon
the subscribers' request.

      The subscribers may buy the terminal equipment from other competing
independent companies and the Concessionaire will be under the obligation to
connect it to the Network to provide the signal communication service. The
Concessionaire will not be under the obligation to provide maintenance services
to terminal equipment bought by the subscribers from another company.

      c) Provide the long distance telephony service to its subscribers through
interconnection to the Public Basic Telephony Network and other
Ministry-licensed public long-distance networks.

      d) Provide the public radiotelephone booths which constitute terminal
equipment which is a part of the Network and are available to the public at
large.

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       7

      1.3. TERMINAL EQUIPMENT MARKETING, INSTALLATION AND MAINTENANCE

      The Concessionaire must market, install and maintain the subscribers'
terminal radio communication equipment under a separate accounting, through
affiliates, subsidiaries or business agents.

      The Concessionaire will be directly liable to the Ministry and its
subscribers for the provision of said services. The contract forms executed by
the Concessionaire with business agents must be previously authorized by the
Ministry.

      1.4. COMPLEMENTARY AND VALUE ADDED CONCESSION SERVICES

      The Concessionaire must secure a permit from the Ministry pursuant to the
applicable legislation in order to provide special complementary
telecommunications and value added or data communication [TELEINFORMATICA]
services.

      The Concessionaire will provide the Concession services, if any, in an
environment of competition under a separate accounting or through affiliates or
subsidiaries, when so indicated by the Ministry.

                            CHAPTER 2. MISCELLANEOUS

      2.1. APPLICABLE LEGISLATION

      The public service which is the subject matter of this Concession Title is
governed by the Political Constitution of the United Mexican States and the
General Means of Communication Law, the General National Property Law [LEY
GENERAL DE BIENES NACIONALES] and their Regulations and by any international
communications agreements, covenants and treaties signed and

<PAGE>

                                       8

ratified by the Mexican Government, by the current legislation and by the terms
of this Concession Title.

      2.2. MAJORITY STOCK TO BE HELD BY MEXICANS

      The Concessionaire will have such equity structure and Board of Directors
that the authority to determine the administrative control and to decide the
Company's management be always vested on Mexican partners.

      Foreign investors may not own over 49% of all the stock.

      2.3. AMENDMENTS TO THE CONCESSIONAIRE'S BY-LAWS

      The Concessionaire will submit to the Ministry, for prior approval, any
amendments to its Charter and By-Laws, capital stock increases, changes in its
equity structure and any amendments to the regulations that govern its relations
with the public.

      2.4. SECURITY INTERESTS AND COMPETITION

      This Concession does not grant the Concessionaire or third parties any
security interests to any public property used to provide the Concession
services; therefore, any monopolistic practice which implies the Concessionaire
hoarding of said property to provide the Concession services will cause the
cancellation of this Concession.

      The Ministry reserves the right to issue one or more concessions to third
parties to provide the same services as or Concession services similar to the
services in the same or a different geographical area.

      The Ministry may issue concessions or permits to

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       9

provide telecommunications services which compete with the Concessionaire's
Concession services. In order to issue other concessions, the Ministry will bear
in mind the efficiency of the services, the Concessionaire's financial soundness
in providing the Concession service and the fair competition conditions.

      2.5. ASSIGNMENT OF RIGHTS

      The Concessionaire may not assign, transfer, mortgage or otherwise dispose
of this Concession or the rights hereunder in whole or in part to third parties
without the Ministry's prior approval.

      If the Ministry issues its consent, the respective contract or agreement
must be subject to the applicable statutes.

      The property mentioned in Article 92 of the General Means of Communication
Law, other than the assigned radio electric spectrum bands, may be mortgaged or
otherwise encumbered.

      2.6 RIGHTS NOT TO BE ASSIGNED TO FOREIGN GOVERNMENTS OR STATES

      The Concessionaire may neither directly nor indirectly assign, mortgage or
otherwise encumber or dispose of this Concession, the rights hereunder granted,
the construction works and facilities, shares, debentures or bonds issued, to
any foreign government or state, or accept any foreign government or state as
shareholder; any transaction carried out which is contrary to this condition
will be null and void.

      Should any foreign government or state acquire any shares, debentures or
bonds issued by the Concessionaire, such

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       10

shares, debentures or bonds will cease to have any value for their holder from
the moment of their acquisition.

      Mexican companies which are Concessionaire shareholders may accept as
minority shareholders any foreign state-owned companies having their own legal
existence and capital if such foreign companies undertake to be regarded as
Mexican nationals in connection with their shares, not to call upon or accept
the diplomatic intervention of their countries of origin or of any other foreign
countries or the intervention of any international public or private agency,
under the penalty of forfeiting, in favor of Mexico, any property of or rights
to the company.

      2.7. RESTRICTION ON GRANTING OF POWERS OF ATTORNEY

      The Concessionaire may grant to companies irrevocable general powers of
attorney for lawsuits and collections, acts of administration and of ownership
which imply the direct or indirect assumption of the Concessionaire' rights and
obligations hereunder.

      2.8. THE CONCESSIONAIRE NOT TO CALL UPON FOREIGN GOVERNMENTS

      The Concessionaire has established to the Ministry that it is incorporated
pursuant to the laws of Mexico and therefore it will not have, as to the
validity, construction or fulfillment of this Concession, any rights or remedies
other than those granted by Mexican laws to Mexicans and, therefore, the
Concessionaire will not request or accept, in connection with everything
pertaining to the provision and turning to account of the Concession services,
the diplomatic intervention of any

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       11

foreign country or of any international public or private agency, under the
penalty of forfeiting, in favor of Mexico, all of the property and rights it may
have acquired to erect, set up and turn to account the means of communications
and [to provide] the Concession services.

      2.9. THE CONCESSIONAIRE NOT TO ENGAGE IN MONOPOLISTIC PRACTICES

      The Concessionaire will not resort to monopolistic practices which prevent
fair competition with other companies in the business it engages in either
directly or indirectly through its affiliates.

      The Concessionaire may not carry out any act or enter into any agreement
or covenant or combination of the above aimed at giving it or other persons an
undue exclusive advantage or at monopolizing any markets that complement the
Concession services.

      2.10. NO CROSS-SUBSIDIES AND PREFERRED TREATMENT

      The Concessionaire may neither receive nor give subsidies or preferred
treatment from or to any other telecommunications service concessionaires, over
other public or private companies or entities. The Concessionaire must report to
the Ministry any action it took in response to any claims of violation of this
Section filed by other companies that provide service which compete with the
Concessionaire's Concession services and by subscribers.

                 CHAPTER 3. NETWORK EXPANSION AND MODERNIZATION

      3.1. NETWORK EXPANSION

      Each year, the Concessionaire will prepare and

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       12

negotiate its five-year program with the Ministry; such program must list the
quality, coverage and modernization goals for the first two years and will be
negotiated with the Ministry in order to make it consistent with the National
Development Plan and the Telecommunications Sector Programs. The Concessionaire
must report each year to the Ministry its fulfillment of the program.

      The Concessionaire must install the Network with a capacity to attend to
at least:

      -4,000 subscribers in seven cities during the first Concession Year.

      -12,000 subscribers in 15 cities during the fifth Concession Year.

      After the fifth year following the granting of this Concession, the
Network must have a Southeastern Region 8 territorial coverage of cities and
townships accounting for at least 75% of the population.

      The Concessionaire undertakes to meet any Ministry-approved quality
standards.

      When installing equipment to be used to run the Network, the
Concessionaire will bear in mind the population's safety and convenience and
property as well as the protection of other utilities, in order not to interfere
with the regular operation of such utilities.

      3.2. NETWORK LINKS

      The Concessionaire may install and run such transmission and switching
infrastructure as it may need in order to transmit the communication, control
and monitoring signals

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       13

among its cellular exchanges and the base radio electric stations and the
stations used to interconnect to the networks of other companies licensed by the
Ministry to provide such services to third parties.

      3.3. RURAL RADIOTELEPHONY

      The Concessionaire will expand the Network coverage in order to provide
Concession services to rural areas pursuant to programs that it negotiates with
the Ministry every five years.

      3.4. PUBLIC RADIOTELEPHONE BOOTHS

      The Concessionaire will set up and keep in operation public radiotelephone
booths within its service area, pursuant to the expansion programs that it
negotiates with the Ministry every five years. The Concessionaire from time to
time will check with the Ministry the guidelines to determine where new public
radiotelephone booths must be installed.

      3.5. TECHNICAL STANDARDS AND PLANS

      The Concessionaire will comply with the technical standards set by the
Ministry and submit to the Ministry its numbering, signaling, transmission,
switching, synchronization and rate-setting plans, bearing in mind the needs of
other public telecommunications service carriers that interconnect to the
Network and those of its end users.

      3.6. OFFICIAL APPROVAL OF EQUIPMENT

      The Concessionaire will install on the Network equipment that meets the
domestic standards and regulations applicable to public telecommunications
networks, which must meet the official approval and registration requirements
set by the

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       14

Ministry.

      In order to facilitate fulfillment of this condition, the Ministry will
promote the establishment and efficient functioning of the Standardization
Consultative Committees [COMITES CONSULTIVOS DE NORMALIZACION] in the industries
in which the Concessionaire or its vendors participate or the accreditation of
testing laboratories.

      3.7. NETWORK CHANGES

      The Concessionaire must secure the Ministry's authorization to make
substantial changes in the Network, if such changes affect the operation of any
devices or other networks interconnected to the Network.

      3.8. NETWORK MODERNIZATION

      The Concessionaire will modernize the Network to provide the Concession
services by introducing technological advances which allow for a greater
utilization of the assigned frequencies, and will improve the Concession service
quality and productivity.

      3.9. TECHNOLOGICAL AND INDUSTRIAL RESEARCH

      The Concessionaire will promote technological and industrial research in
the field of mobile cellular radiotelephony and similar services through
programs coordinated with the Mexican Communications Institute [INSTITUTO
MEXICANO DE COMUNICACIONES] and other research and development institutions.

      The Concessionaire will provide assistance to modernize the Ministry's
radio electric spectrum monitoring and control infrastructure, in the terms set
by the Ministry.

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       15

      3.10. TECHNOLOGICAL TRAINING AND EDUCATION

      The Concessionaire will draw up personnel training and education programs
in order to keep them abreast of technological developments and will devise
technological education support programs in coordination with the higher
education institutions of Mexico, so as to thereby promote the development of
radio communications professionals.

                    CHAPTER 4. SERVICE OPERATION AND QUALITY

      4.1. SERVICE QUALITY AND CONTINUITY

      The Concessionaire will provide the public service in a continued and
efficient manner, abiding by the quality and operation standards approved by the
Ministry.

      The Concession Network must be capable of handling calls from its
subscribers with a 0.02 [%] blockage probability, and be capable to establish a
connection within less than 10 seconds in 80% of the cases, provided that no
Concessionaire-attributable causes are involved.

      The Concessionaire will set up a service quality metering and control
system that must be transparent, reliable and easy to check by the Ministry. The
system must include at least the parameters related to the quality goals and
standards set.

      4.2. EQUAL TREATMENT

      In providing the Concession services, the Concessionaire may not grant
privileges or preferences to or discriminate against specific individuals or
entities.

      4.3. SERVICE CONFIDENTIALITY

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<PAGE>

                                       16

      The Concessionaire must guarantee the confidentiality of the information
provided by the subscribers or generated from the Network in providing the
Concession services to the subscribers and will not disclose such information
without the prior consent to do so.

      4.4. TELEPHONE BOOK

      The Concessionaire must provide telephone book access services only where
a subscriber has not formally requested such Concession services.

      4.5. COMPLAINT AND REPAIR SYSTEM

      The Concessionaire will set up an efficient system to receive complaints
and to repair Network failures, and will report to the Ministry, each month, the
number of complaints, the result of the repairs and the applications of any
credits due to service interruptions and other compensations for failure to meet
the quality standards.

      4.6. METERING AND QUALITY CONTROL EQUIPMENT

      Every two years, the Concessionaire will publish a Ministry-approved
service quality standard system which will be updated from time to time to adapt
it to international standards. Such system must set the compensations to which
each subscriber will be entitled if the Concessionaire fails to meet the quality
standards set.

      The Concessionaire will take all reasonable steps to assure the accuracy
and reliability of any metering device used in relation to the Network for
quality measuring and billing; it will also keep such records as the Ministry
may deem necessary in

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       17

connection with any metering device that the Ministry believes to be a source of
trouble.

      The Concessionaire will allow the Ministry to check and inspect how any
metering device is used and must allow tests to be made of such metering device
in order to appraise its accuracy, reliability and standard fulfillment.

      4.7. SERVICE INTERRUPTION

      If the service is interrupted for over 72 consecutive hours, the
Concessionaire will credit to the subscribers the part of the fees corresponding
to the duration of the interruption, even if the suspension is due to acts of
God or force majeure, without prejudice of any administrative penalty that may
be in order.

      4.8. EMERGENCY CONCESSION SERVICES

      The Concessionaire must prepare a plan, to be approved by the Ministry, in
order to provide emergency services in cases of acts of God or force majeure.

      The Concessionaire will provide the emergency services for free within its
coverage area; likewise, it will assist relief institutions and organizations by
transmitting their messages on a priority basis. The Concessionaire will provide
the security and emergency relief services based on the applicable international
treaties.

      4.9. BUSINESS PRACTICES CODE

      During the first six months following the Concession issue date, the
Concessionaire must deliver to its subscribers a business practices code that
will govern its relations with them

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       18

and which must be previously approved by the Ministry. The code will serve as a
guide for the Concessionaire' customers and employees in connection with any
dispute or complaint related to the provision of the services. The Ministry and
the Concessionaire will jointly revise this code every three years.

      4.10. SERVICE CONTRACT

      The Concessionaire must sign service contracts with all subscribers, which
will set the general conditions to provide the services. Said contract may not
be inconsistent with the Concession conditions and will be voluntary for the
parties. The model contract must be submitted to the Ministry for prior
approval.

      4.11. LIABILITY TO SUBSCRIBERS

      The Concessionaire will be the only party liable to the Ministry for the
provision of the services, and therefore the Ministry will be relieved from any
liability to the Concessionaire's subscribers. Should the Concessionaire fail to
provide the services in the terms and conditions of this Concession Title, the
Ministry will take the proper steps.

      4.12. NO TIE-IN SALES ALLOWED

      The Concessionaire may not force any subscriber to buy other goods,
services or securities, as a condition to provide the requested services, unless
due to unavoidable technical conditions.

      4.13. NO EXCLUSIVE VENDOR

      The Concessionaire may not subject its procurement of telecommunications
materials and equipment or services generally

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<PAGE>

                                       19

to the condition that the vendor sell such goods or provide such services only
to the Concessionaire.

                           CHAPTER 5. INTERCONNECTION

      5.1. INTERCONNECTION TO THE BASIC PUBLIC TELEPHONY NETWORK

      The Concessionaire will interconnect the Network to the basic public
telephony network given under concession to Telefonos de Mexico, S.A. de C.V.
(`Telmex'), and for this purpose it must enter into an interconnection agreement
which will take into consideration the following, inter alia:

      1) The method adopted to set up and maintain the connection.

      2) The Network connection points where the connection will take place,
including arrangements to determine the point where the signals are transferred
from one telecommunications network to another and arrangements to transmit and
route signals in emergency situations.

      3) The dates on or periods in which the Concessionaire or Telmex
undertakes to carry out the interconnection commitments.

      4) The necessary capacity in order for the traffic of signals between the
Network and other networks to have a reasonable quality.

      5) The dates or periods set by the Concessionaire and Telmex to review the
contract terms or conditions.

      6) How the signals must be transmitted from or received at the Network
terminal points, including numbering

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       20

arrangements and signaling methods.

      7) How to make sure that any signal is received with a quality consistent
with the recommendations of the International Telecommunication Union accepted
by the United Mexican States or any other standard accepted by the Ministry from
time to time.

      8) The collection arrangements between the parties for signals transmitted
to third parties by virtue of the interconnection, inside or outside the
Republic of Mexico.

      9) Reserves to meet either party's contingent obligations as a result of
the interconnection.

      10) Any charges and rates payable by the Concessionaire to Telmex.

      11) Any other issue that the Ministry believes should be agreed upon by
the Concessionaire and Telmex.

      If after a period that the Ministry considers reasonable the
Concessionaire and Telmex have not reached an interconnection agreement, the
Ministry, upon either party's request, will set the terms of any conditions that
the Concessionaire and Telmex were unable to agree upon, making sure that the
following matters are agreed upon:

      a) The Concessionaire will pay Telmex for the cost of everything that may
be necessary in order to set up and maintain the connection, by means of an
arrangement that includes a full allotment of the attributable costs of any
services which are provided.

      b) That Telmex be properly indemnified against any third party obligations
or Network damages arising out of the

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<PAGE>

                                       21

interconnection.

      c) That the quality of all telecommunications services provided with the
Network and other networks connected to the Network be preserved.

      d) That the fair competition requirements be met.

      e) That any other issue that may be necessary in order to equally protect
Telmex's and the Concessionaire's interests be taken into consideration,
including the need to make sure:

      -That the interconnection arrangements are consistent with acceptable
engineering principles and practices;

      -That the Concessionaire is not forced to unduly depend on the services
provided by Telmex;

      -That Telmex's obligations to the Concessionaire be determined duly taking
into consideration the obligation to set up connection points for others;

      -That any arrangements made under this condition be as similar as practice
allows for all carriers, notwithstanding the variety of carriers that may enter
into contracts with Telmex pursuant to this condition;

      -That Telmex's commercial and confidential information be properly
protected;

      -That the Network's technical evolution and numbering arrangements be not
limited more than to the extent that may be necessary.

      f) That the interconnection and other service costs to the Concessionaire
reflect the cost of providing them and be internationally competitive.

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<PAGE>

                                       22

      The Concessionaire will not be under the obligation to enter into
interconnection agreements with carriers in any of the following events:

      i) In the event that in the Concessionaire's opinion so doing might
endanger the life of security of human beings or cause death or casualties and
property damage or impair the quality of any telecommunications services
provided through the Network, and the Ministry does not issue an opinion to the
contrary; or

      ii) If in the Concessionaire's opinion it is not necessary to request the
connection or permit the connection to be made in the time and as required by
the Concessionaire, bearing in mind the Network's state of the art or any other
aspect that may be relevant and the Ministry does not issue an opinion to the
contrary.

      The Concessionaire must connect and provide the service to any subscriber
that requests the same, if the subscriber has terminal equipment approved by the
Ministry and must not force the subscriber to buy the equipment, or other goods
or Concession services, from the Concessionaire as a condition to provide the
requested service.

      5.2. INTERCONNECTION TO OTHER PRIVATE AND PUBLIC NETWORKS

      The Concessionaire will interconnect the Network to other public networks
authorized by the Ministry that formally so request, as well as to private
networks in such terms as they may agree upon.

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<PAGE>

                                       23

      If no agreement is reached in the interconnection negotiations, the
Ministry will decide accordingly. If the public interest so demands, the
Concessionaire will combine its services with other authorized
telecommunications services.

      5.3. COMMUNICATION OF USERS OF NETWORKS FROM OTHER REGIONS

      The Concessionaire will conduct the corresponding negotiations in order
for any of its subscribers that so request may use the cellular mobile
radiotelephony services in the networks licensed in other regions, and in order
for subscribers of other networks to use the Concessionaire's Network.

      In the event that no agreement is reached, the Ministry will decide
accordingly.

      The Concessionaire in turn will take the necessary steps in order for its
subscribers to the able to intercommunicate with other carriers' radiotelephony
networks.

      5.4. INTERCONNECTION CAPACITY AND QUALITY

      The Concessionaire will install sufficient capacity in order to meet the
interconnection services demand, pursuant to the Ministry-approved technical
standards and the terms and conditions of any contracts entered into.

      The Concessionaire will neither affect the quality nor interfere with the
provision of the services of other interconnected networks or equipment.

      5.5. INTERCONNECTION TO FOREIGN NETWORKS

      If in order to interconnect the Concessionaire' Network to foreign
networks it were necessary to sign an agreement with a

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       24

foreign government, the Concessionaire will carry out with the Federal
Government, through the Ministry, the steps that may be necessary to sign the
corresponding agreement.

      If a foreign carrier is involved, the Concessionaire will need the
Ministry's prior authorization for the execution of the interconnection
agreement with the foreign network and will submit correct copies of the
agreements to be signed. The Ministry may request changes to the agreements if
in its opinion they may unduly affect the interests of other network operators,
the Network users or the country as a whole.

      The Concessionaire will not unreasonably prevent any other
telecommunications carrier from connecting its network to any network located
outside of the Republic of Mexico or from participating in any international
agreement.

               CHAPTER 6. RATE REGULATIONS AND FINANCIAL SOUNDNESS

      6.1. APPLICABLE RATES

      The Concessionaire will submit to the Ministry, for approval, the maximum
rates for the Concession services it provides, which must be competitive
worldwide. The Concessionaire will submit rate studies to the Ministry which
must include productivity improvements and service costs.

      If in the Ministry's opinion sufficient competition may be generated in
the service provided by the Concessionaire, a greater rate control flexibility
may be authorized.

      The competitive rates will be approved provided that they do not imply a
direct loss from the service provision.

      6.2. COST ACCOUNTING

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                                       25

      The Concessionaire must carry a service cost and revenues accounting
system, which identifies the service functioning.

      The accounting records to which this paragraph refers must properly show
the costs (including cost of capital), revenues, assets, employees and
liabilities attributable to each service. The Ministry may ask the
Concessionaire to provide reports each fiscal year or more often, as specified,
but no more frequently than every quarter.

      6.3. PUBLIC BOOTH RATES

      The maximum public booth rates will be those authorized for the urban and
suburban radiotelephone service.

      6.4. RATES TO BE PUBLISHED

      The Concessionaire must publish at least once every year on the Official
Gazette of the Federation and on the country's largest circulation dailies, the
maximum rates, conditions and charges for the services that it provides.

      6.5. REVENUE SHARING

      The Concessionaire will pay to the Federal Government, as the latter's
initial share pursuant to Article 110 of the General Means of Communications
Law, Ps.13,500,000,000 as follows: 50% prior to receiving this Concession, 25%
within a maximum 90-calendar-day term, and 25% within a maximum 180-calendar-day
term, following the date [hereof], plus a yearly 6% share of the gross revenues
earned from the provision of the Concession services.

      The Concessionaire will pay said share every six months

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<PAGE>

                                       26

within the first month following the end of the service semester, in Mexican
currency, at the Federal Treasury Office, with a document issued in favor of the
Ministry.

      If after the granting of this Concession Title some other type of
compensation is set or established on the turning to account or utilization of
the general means of communication which is the subject matter of this
Concession or else the provision of the public cellular mobile radiotelephony
service, the percentage share of the revenues to which this clause refers will
be reduced accordingly.

      In order to guarantee payment of any unpaid percentage of the initial
share to which this condition refers, the Concessionaire shall post the bond
that covers the corresponding unpaid amounts before receiving this Concession
Title, issued by a qualified bonding company. The bond policy will expressly
state that the bonding company accepts the provisions of Articles 95 and 118 of
the current Federal Bonding Company Law [LEY FEDERAL DE INSTITUCIONES DE
FIANZAS] and that it waives the benefit of order and excussio, pursuant to the
policy model approved by the Federal Treasury Office

      6.4. BILLING

      The Concessionaire must bill to the subscribers the amount owing for the
Concession services provided, with a breakdown of each type of service, and with
an indication, in the case of metered services, of the time used or the number
of messages transmitted. Information on additional services must also be
provided.

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<PAGE>

                                       27

               CHAPTER 7. INSPECTION, SUPERVISION AND INFORMATION

      7.1. INSPECTION

      The Ministry will at all times have the authority to supervise and inspect
the facilities of and the services provided by the Concessionaire and the latter
will provide the Ministry all of such assistance as the Ministry may need, in
accordance with the applicable statutes and regulations.

      7.2. EXPANSION GOAL EVALUATION

      The Concessionaire must report each year to the Ministry the progress of
the expansion program mentioned in Chapter 3. The Ministry will evaluate
fulfillment of the established goals.

      7.3. QUALITY SERVICE EVALUATION

      The Ministry will check and evaluate the quality of the services provided
by the Concessionaire, pursuant to Chapter 4. In order to make such evaluation,
the Ministry will make independent, random and permanent samplings of the
qualities so measured, thus verifying the information shown in the
Concessionaire' control system.

      7.4. TECHNICAL AND STATISTICAL DATA

      The Concessionaire will submit technical, administrative and financial
information to the Ministry, in accordance with the applicable statutes and
regulations, and the Ministry will keep such information confidential.

                  CHAPTER 8. TERM, TERMINATION AND CANCELLATION

      8.1. CONCESSION TERM AND REVISION

      This Concession will be in effect for 20 years

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<PAGE>

                                       28

following its issue date and will be revised whenever the parties agree that so
doing is necessary.

      The Concession will be up for revision as to expansion, modernization,
operation, service quality and rates as often and as provided in the respective
chapters of this Concession Title.

      The amendments, if any, will become effective one year after their
approval. The Concessionaire will publish at its expense, on the Official
Gazette of the Federation, the amendments to the Concession Title conditions.

      8.2. CONCESSION EXTENSION

      This Concession may be extended provided that the Concessionaire has met
the conditions of this Title, has not suffered an event of cancellation, so
requests five years prior to the expiration of this Concession, and accepts the
new conditions to provide the services set by the Ministry with the public
interest in mind.

      The Ministry, within no more than 180 days following the Concessionaire's
application, will decide on the extension as provided in the preceding
paragraph.

      8.3. REVERSION RIGHT

      Upon the expiration of this Concession and its extensions, if any, the
property and rights used to turn the services to account will revert to the
Nation pursuant to the applicable laws.

      8.4. EVENTS OF CANCELLATION

      This Concession will be canceled in any of the following events, in
addition to the events provided for in the

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       29

[General Means of Communication] Law :

      A) In the event that the Concessionaire does not efficiently and regularly
provide the Concession services, in accordance with the quality standards set,
notwithstanding the Ministry's written demand to do so.

      B) In the event that the services are suspended in whole or in part
without the Ministry's prior authorization and without cause.

      C) In the event that the expansion goals and conditions are not met.

      D) In the event that the authorized facilities or the service operation
conditions are substantially changed or altered without the Ministry's previous
approval.

      E) In the event of serious and repeated violations of the conditions of
this Title, after being advised in writing by the Ministry of said violations.

      F) In the event that [the Concessionaire] refuses to interconnect other
radiotelephone service concessionaires without cause and with the Ministry's
prior warning.

      G) In the event that the Concessionaire allows foreign investors to own
over 49% of its voting stock or in the event that foreign investors have the
power to determine the Concessionaire's management.

      H) In the event that the Concessionaire provides, without the Ministry's
authorization, telecommunications services other than the Concession services
which must be previously authorized by the Ministry.

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<PAGE>

                                       30

      I) In the event that the Concessionaire hides data or refuses to provide
information to the Ministry without cause.

      J) In the event of the Concessionaire' voluntary or court-ordered
bankruptcy.

      K) In the event that the Concessionaire does not pay the State's revenue
share.

      L) In the event that due to violations of Section 2.10, which forbids
cross-subsidies and preferred treatment, [the Concessionaire] refuses to abide
by the Ministry's directions.

      M) In the event that the assets which are necessary for the public service
[to be provided] are assigned, encumbered or otherwise transferred without the
Ministry's prior authorization.

      The Concession cancellation will be subject to the procedure set by the
General Means of Communication Law.

      8.5. CONCESSION SCOPE REDUCTION

      The Concession scope for a specific zone or service may be reduced in any
of the events mentioned in paragraphs A), B) and C) of condition 8.4 for such
specific zone or service.

      8.6. GUARANTY OR BOND

      In order to guarantee fulfillment of its obligations hereunder, the
Concessionaire will post a Ps.1,500,000,000 bond within no more than 30 days
following the Concession date, through a qualified bonding company, in favor of
the Federal Treasury Office. This bond will remain in effect throughout the
Concession term and the Concessionaire will increase the same within no more
than ten business days, if so doing is necessary

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<PAGE>

                                       31

in the Ministry's opinion.

      The bond policy will expressly state that the bonding company accepts the
provisions of Articles 95 and 118 of the current Federal Bonding Company Law and
that it waives the benefit of order and excussio, pursuant to the policy model
approved by the Federal Treasury Office.

      8.7. PENALTIES

      The Ministry will apply to the Concessionaire the administrative penalties
contained in the laws and regulations applicable to the Concession services and
the penalties provided for by this Title, without prejudice of the penalties to
be imposed by other agencies within the scope of their authority.

      The penalties will be applied by the Ministry pursuant to the procedure
set in Article 34 of the General Means of Communication Law.

      8.8. ADMINISTRATIVE AND JUDICIAL JURISDICTION

      For everything pertaining to the construction and fulfillment of this
Concession Title, other than any administrative matters to be handled by the
Ministry, the Concessionaire agrees to submit to the jurisdiction of the Federal
Courts of the City of Mexico, Federal District, and waives the venue of any
other court to which it may be subject by virtue of its present or future
domicile.

                    Mexico, Federal District, July 17, 1990.

THE MINISTER OF COMMUNICATIONS      PORTATEL DEL SURESTE,
      AND TRANSPORT                 S. A. DE C. V.

(An illegible signature)            (An illegible signature)
Andres Caso Lombardo                Luis Miguel Nino de
                                    Rivera Taracena.

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<PAGE>

                                       32

                                   EXHIBIT `A'

                                COVERAGE PROGRAM

<TABLE>
<CAPTION>
CITIES                                                          YEAR OF OPERATION*
----------------------------------------------------------------------------------
<S>                                                             <C>
Campeche                                                               First
Cancun                                                                 First
Chetumal                                                               First
Merida                                                                 First
Tuxtla Gutierrez                                                       First
Villa Hermosa                                                          First
Tapachula                                                              First
Comacalco                                                              Second
Cd. del Carmen                                                         Second
Puerto Progreso                                                        Third
Teapa                                                                  Third
San Cristobal                                                          Third
Huixtla                                                                Third
Cozumel                                                                Third
Tulum                                                                  Third

HIGHWAYS
1.  Villahermosa-Comacalco-Cordoba                                     First
2.  Merida-Valladolid                                                  Second
3.  Tuxtla Gutierrez-San Cristobal                                     Third
4.  Cancun-Valladolid                                                  Third
5.  Cancun-Chetumal                                                    Fourth
6.  Campeche-Villahermosa                                              Fourth
7.  Tapachula-Comitan-San Cristobal                                    Fifth
8.  Tapachula-Tonala-Tuxtla                                            Fifth
</TABLE>

--------------------------
*The first year of operation will run from the Concession Title delivery date
onward.

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                                       33

                                   EXHIBIT `B'

                       TECHNICAL EMISSION CHARACTERISTICS

      The systems used to provide the public cellular telephony service must run
pursuant to the following parameters:

<TABLE>

<S>   <C>                                       <C>
1.    Frequency Band,
      Cellular System A:                        825-835 MHz/870-880 MHz
2.    Radio electric frequency duplex
      channels (see Charts 1 and 2)
      Cellular system:                          333 frequency pairs
3.    Assigned radio electric spectrum,
      Cellular system:                          20 MHz
4.    Channel separation:                       30 MHz
5.    Tx and Rx separation:                     45 MHz
6.    Maximum frequency deviation:              +/- 12 KHz
7.    Maximum apparent radiated power:
      7.1.  Mobile stations:                    7 watts
      7.2. Ancillary testing stations:          7 watts
8.    Type of emission:
      8.1  Control channels                     Frequency modulation in a double- or multiple channel system with
                                                quantified or digital information, plus one or more channels with analog
                                                information where the type of information to be transmitted is uncertain

      8.2 Voice channels                        Single-channel frequency modulation with analog telephony
                                                information
9.    Emission denomination:                    40K0F9X or 40K0F3E
</TABLE>

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<PAGE>

                                       34

                                     CHART 1

                        825-835 MHz and 970-880 MHz Bands

                                    Block `A'

<TABLE>
<CAPTION>
  CHANNEL              MOBILE              BASE              CHANNEL            MOBILE               BASE
 N(degree)           FREQUENCY             (MHz)            N(degree)          FREQUENCY             (MHz)
<S>                  <C>                  <C>               <C>                <C>                  <C>
       173            830.190             875.190                216            831.480             876.480
       174            830.220             875.220                217            831.510             876.510
       175            830.250             875.250                218            831.540             876.540
       176            830.280             875.280                219            831.570             876.570
       177            830.310             875.310                220            831.600             876.600
       178            830.340             875.340                221            831.630             876.630
       179            830.370             875.370                222            831.660             876.660
       180            830.400             875.400                223            831.690             876.690
       181            830.430             875.430                224            831.720             876.720
       182            830.460             875.460                225            831.750             876.750
       183            830.490             875.490                226            831.780             876.780
       184            830.520             875.520                227            831.810             876.810
       185            830.550             875.550                228            831.840             876.840
       186            830.580             875.580                229            831.870             876.870
       187            830.610             875.610                230            831.900             876.900
       188            830.640             875.640                231            831.930             876.930
       189            830.670             875.670                232            831.960             876.960
       190            830.700             875.700                233            831.990             876.990
       191            830.730             875.730                234            832.020             877.020
       192            830.760             875.760                235            832.050             877.050
       193            830.790             875.790                236            832.080             877.080
       194            830.820             875.820                237            832.110             877.110
       195            830.850             875.850                238            832.140             877.140
       196            830.880             875.880                239            832.170             877.170
       197            830.910             875.910                240            832.200             877.200
       198            830.940             875.940                241            832.230             877.230
       199            830.970             875.970                242            832.260             877.260
       200            831.000             876.000                243            832.290             877.290
       201            831.030             876.030                244            832.320             877.320
       202            831.060             876.060                245            832.350             877.350
       203            831.090             876.090                246            832.380             877.380
       204            831.120             876.120                247            832.410             877.410
       205            831.150             876.150                248            832.440             877.440
       206            831.180             876.180                249            832.470             877.470
       207            831.210             876.210                250            832.500             877.500
       208            831.240             876.240                251            832.530             877.530
       209            831.270             876.270                252            832.560             877.560
       210            831.300             876.300                253            832.590             877.590
       211            831.330             876.330                254            832.620             877.620
       212            831.360             876.360                255            832.650             877.650
       213            831.390             876.390                256            832.680             877.680
       214            831.420             876.420                257            832.710             877.710
       215            831.450             876.450                258            832.740             877.740
</TABLE>

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       35

<TABLE>
<CAPTION>
 CHANNEL             MOBILE              BASE              CHANNEL            MOBILE               BASE
N(degree)          FREQUENCY             (MHz)            N(degree)          FREQUENCY             (MHz)
<S>                <C>                  <C>               <C>                <C>                  <C>
     259            832.770             877.770                 302           834.060             879.060
     260            832.800             877.800                 303           834.090             879.090
     261            832.830             877.830                 304           834.120             879.120
     262            832.860             877.860                 305           834.150             879.150
     263            832.890             877.890                 306           834.180             879.180
     264            832.920             877.920                 307           834.210             879.210
     265            832.950             877.950                 308           834.240             879.240
     266            832.980             877.980                 309           834.270             879.270
     267            833.010             878.010                 310           834.300             879.300
     268            833.040             878.040                 311           834.330             879.330
     269            833.070             878.070                 312           834.360             879.360
     270            833.100             878.100                 313           834.390             879.390
     271            833.130             878.130                 314           834.420             879.420
     272            833.160             878.160                 315           834.450             879.450
     273            833.190             878.190                 316           834.480             879.480
     274            833.220             878.220                 317           834.510             879.510
     275            833.250             878.250                 318           834.540             879.540
     276            833.280             878.280                 319           834.570             879.570
     277            833.310             878.310                 320           834.600             879.600
     278            833.340             878.340                 321           834.630             879.630
     279            833.370             878.370                 322           834.660             879.660
     280            833.400             878.400                 323           834.690             879.690
     281            833.430             878.430                 324           834.720             879.720
     282            833.460             878.460                 325           834.750             879.750
     283            833.490             878.490                 326           834.780             879.780
     284            833.520             878.520                 327           834.810             879.810
     285            833.550             878.550                 328           834.840             879.840
     286            833.580             878.580                 329           834.870             879.870
     287            833.610             878.610                 330           834.900             879.900
     288            833.640             878.640                 331           834.930             879.930
     289            833.670             878.670                 332           834.960             879.960
     290            833.700             878.700                 333           834.990             879.990
     291            833.730             878.730
     292            833.760             878.760
     293            833.790             878.790
     294            833.820             878.820
     295            833.850             878.850
     296            833.880             878.880
     297            833.910             878.910
     298            833.940             878.940
     299            833.970             878.970
     300            834.000             879.000
     301            834.030             879.030
</TABLE>

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V
<PAGE>

                                       36

                                     CHART 2

                                    BLOCK `A'

<TABLE>
<CAPTION>
Channel N(degree)      Mobile Frequency             Base (MHz)
<S>                    <C>                          <C>
   313                      834.390                  879.390
   314                      834.420                  879.420
   315                      834.450                  879.450
   316                      834.480                  879.480
   317                      834.510                  879.510
   318                      834.540                  879.540
   319                      834.570                  879.570
   320                      834.600                  879.600
   321                      834.630                  879.630
   322                      834.660                  879.660
   323                      834.690                  879.690
   324                      834.720                  879.720
   325                      834.750                  879.750
   326                      834.780                  879.780
   327                      834.810                  879.810
   328                      834.840                  879.840
   329                      834.870                  879.870
   330                      834.900                  879.900
   331                      834.930                  879.930
   332                      834.960                  879.960
   333                      834.990                  879.990."
</TABLE>

JNNR. MMG. SCT OFFICIAL LETTER & CONCESSION TITLE. PORTATEL DEL SURESTE/V

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