Draft Rev A June 13, 2001                                           CONFIDENTIAL

SUBLEASE                                                    EXHIBIT NUMBER 10.35

     THIS SUBLEASE (the  "Sublease") is entered into as of the date set forth in
Section 1.1 (e) below,  by and between the  Sublandlord  and the  Subtenant  set
forth below.

                               W I T N E S S E T H

     1. SUBLEASE SUMMARY AND DEFINITIONS.

     1.1 The Sublease  provisions and  definitions set forth in this Section 1.1
in summary form are solely to facilitate convenient reference by the parties. If
there is any  conflict  between this  Section and any other  provisions  of this
Sublease, the latter shall control.

(a)  SUBLANDLORD'S NAME                TCSI CORPORATION
     AND ADDRESS:                      1080 Marina Village Parkway
                                       Alameda, California 94501
                                       Attention: Chief Financial Officer

(b)  SUBLANDLORD'S STATE
     OF INCORPORATION:                 NEVADA

(c)  SUBTENANT'S NAME                  METRO PCS
     AND ADDRESS:                      1080 Marina Village Parkway
                                       Fourth Floor
                                       Alameda, CA 94501
                                       Attn:  Chief Financial Officer

(d)  SUBTENANT'S STATE
     OF INCORPORATION:                 Delaware

(e)  SUBLEASE DATE:                    August 4, 2001

(f)  OVERSUBLANDLORD'S                 COMPUTER ASSOCIATES INTERNATIONAL, INC.
     NAME AND ADDRESS:                 1 Computer Associates Plaza
                                       Islandia, NY  11788-7000
                                       Attention: Senior Vice President -
                                                  Facilities

(g)  OVERSUBLEASE:                     Sublease dated July 12, 1996, between
                                       Sublandlord and Oversublandlord.

(h)  OVERLANDLORD'S                    ALAMEDA REAL ESTATE INVESTMENTS
     NAME AND ADDRESS:                 1150 Marina Village Parkway, Suite 100
                                       Alameda, CA 94501
                                       Attention: Peter Edelen


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(i)  OVERLEASE:                        Lease dated June 25, 1992, between
                                       Overlandlord and Oversublandlord, as
                                       amended by Amendment No. 1, dated January
                                       29, 1993, and Amendment No. 2, dated
                                       December 1, 1994.

(j)  PREMISES:                         Approximately 17,568 rentable square feet
                                       on the fourth floor of 1080 Marina
                                       Village Parkway, Alameda, California
                                       described in Exhibit "A," hereto (the
                                       "Premises). Prior to the Sublease
                                       Commencement Date, Sublandlord and
                                       Subtenant shall cause the Premises to be
                                       measured to determine the rentable square
                                       feet of the Premises (the "Rentable
                                       Square Footage") under the American
                                       National Standard Method for Measuring
                                       Floor Area in Office Buildings,
                                       ANSIZ65.1--1980 (reaffirmed 1989) or
                                       successor standard(s), adopted by the
                                       Building Owners and Managers Association
                                       International.

(k)  SUBLEASE COMMENCEMENT DATE:       July 15, 2001, or upon approval by
                                       Over-Landlord or OverSublandlord,
                                       whichever is later. (See Article 3,
                                       herein.)

(l)  SUBLEASE EXPIRATION DATE:         September 30, 2004

(m)  BASE MONTHLY RENT:                The initial Base Monthly Rent (the
                                       "Initial Base Monthly Rent") shall be an
                                       amount arrived at by multiplying the
                                       Rentable Square Footage by One Dollar and
                                       Ninety cents ($1.90) (full service).

(n)  EARLY ACCESS:                     Sublandlord will grant Subtenant up to
                                       two week early access to the Premises
                                       upon execution of the Sublease agreement
                                       by Subtenant and Sublandlord and
                                       Sublandlord vacating the premises.

(o)  OPERATING EXPENSES/TAXES:         Subtenant will be responsible for paying
                                       operating expenses over the Base Year
                                       2001 for operating expenses and a Base
                                       Year 2000/2001 for taxes.


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(p)  SECURITY DEPOSIT:                 A sum equal to four (4) months of Base
                                       Rent in the form of cash or a letter of
                                       credit at an institution of Subtenant's
                                       choice and shall occur upon a fully
                                       executed lease agreement.

(q)  ALTERATIONS:                      (See Article 8, herein.)

(r)  BASE YEAR:                        January 1 - December 31, 2001

(s)  BROKERS:
     For SUBLANDLORD:                  AEGIS REALTY PARTNERS

     For SUBTENANT:                    CM REALTY

(t)  BROKER COMMISSIONS                Subtenant shall pay six percent (6%)
                                       based on the listing agreement between
                                       Sublandlord and Aegis Realty Partners
                                       ("Listing Broker") to be split equally
                                       between the Listing Broker and CM Realty.

(u)  SUBTENANT'S PROPORTIONAL SHARE:   20.685%

(v)  BUILDING:                         The "Building" is that certain office
                                       building commonly known as 1080 Marina
                                       Village Parkway, Alameda, California.

     2. SUBLEASE GRANT.

     2.1. By lease (hereinafter referred to as the "Overlease") described above,
the Overlandlord  leased to Oversublandlord  the Premises in accordance with the
terms of the Overlease.  A copy of the Overlease has been received by Subtenant.
By Sublease (hereinafter referred to as the "Oversublease"), the Oversublandlord
leased  to  Sublandlord  the  Premises  in  accordance  with  the  terms  of the
Oversublease. A copy of the Oversublease has been received by Subtenant.

     2.2. In  consideration of the obligation of Subtenant to pay rent as herein
provided and in  consideration  of the other  terms,  covenants  and  conditions
hereof,  Sublandlord hereby leases to Subtenant and Subtenant hereby leases from
Sublandlord,   upon  and  subject  to  the  provisions  of  this  Sublease,  the
Oversublease and the Overlease, the Premises.

     3. SUBLEASE TERM.

     3.1. Subject to the other provisions  hereof,  this Sublease shall continue
in full force and effect for a term beginning on the Sublease  Commencement Date
and ending


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on the Sublease Expiration Date as defined above. Such term is herein called the
"Sublease Term."

     3.2. The Sublease  Commencement  Date shall be date as set forth in Section
1.1(k).  If for any reason there is a delay in the Sublease  Commencement  Date,
Sublandlord  shall not be subject  to any  liability  therefore,  nor shall such
failure  affect the validity of this Sublease,  or the  obligations of Subtenant
hereunder,  or extend the term hereof,  provided,  however, that if the Sublease
Commencement  Date is not on or before September 1, 2001,  Subtenant may, in its
sole discretion, terminate this Sublease.

     3.3.  Sublandlord  will grant  Subtenant  early access to the Premises upon
execution  of  the  sublease   agreement  by  Subtenant  and  Sublandlord,   and
Sublandlord will no longer show the Premises to any other party.

     4. RENT.

     4.1.  Subtenant,  in  consideration  of  this  Sublease,  agrees  to pay to
Sublandlord  as rent (the "Base Monthly  Rent") the amounts set forth in Section
1.1 (m), hereof.  Base Monthly Rent is payable in advance and without demand, at
Sublandlord's  office (or such other location as Sublandlord  shall designate in
writing) by check, in monthly  installments on the first (1st) day of each month
during the Sublease  Term without any set-off,  off-set,  abatement or reduction
whatsoever.  Subtenant's  failure to receive an invoice from Sublandlord for the
rent  shall  not  relieve  Subtenant  from  its  obligation  of  timely  payment
hereunder.  In the event the Sublease Commencement Date is after the first (1st)
day of the month, Subtenant shall be entitled to a prorated credit for each such
day after the first (1st) day of the month to be applied toward the next month's
payment.

     4.2.  Effective  July 15 of each  calendar  year,  following  the  Sublease
Commencement  Date,  of the  Sublease  Term,  the  Base  Monthly  Rent  shall be
increased by multiplying  the Base Monthly Rent in effect during the immediately
preceding  calendar  month by a fraction,  the numerator of which is one hundred
four (104) and the denominator of which is one hundred (100).

     4.3. As used in this Sublease, "Rent" shall mean the Base Monthly Rent, the
Operating  Expense  reimbursements  pursuant to Sections 1.1 (o) and Article 13,
and all other monetary  obligations  provided for in this Sublease to be paid by
Subtenant, all of which constitute rental in consideration for this Sublease.

     4.4.  In the event the Rent is not paid by the fifth (5th) day of any given
month,  interest  shall accrue  thereon at the maximum rate permitted by law. In
addition,  if the rent is not paid by the tenth  (10th) day of any given  month,
Subtenant shall pay to Sublandlord, as liquidated damages, and not as a penalty,
an additional amount equal to five percent (5%) of the rent that is due, but not
less than One Hundred Dollars ($100.00).

     4.5. Anything  contained in any provisions of this Sublease to the contrary
notwithstanding,  in  consideration  of Subtenant  paying the  security  deposit
pursuant to Section 1.1 (m), Base Monthly Rent shall Commence on July 15, 2001.


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     5. ASSIGNMENT OF SUBLETTING.

Sublandlord  and  Subtenant  hereby  adopt the  provisions  of  Section 6 of the
Oversublease  with  respect  to  assignment  and  subleasing  of  the  Premises.
Notwithstanding  the foregoing,  any assignment or subleasing by Subtenant shall
be expressly conditioned upon the receipt of consent by the Oversublandlord.

     6. TERMS OF THE OVERLEASE AND OVERSUBLEASE.

     6.1.  Except as herein  otherwise  expressly  provided,  and except for the
obligation  to pay  rent  and  additional  rent  under  the  Overlease  and  the
Oversublease  (collectively,  the  "Overleases"),  all of the terms,  covenants,
conditions and provisions in the Overleases are hereby incorporated in, and made
a part of, this  Sublease,  and such rights and  obligations as are contained in
the  Overleases  are hereby  imposed upon the  respective  parties  hereto;  the
Sublandlord  herein being  substituted for the landlords in the Overleases,  and
the Subtenant herein being  substituted for the tenants named in the Overleases;
provided,  however,  that the  Sublandlord  herein  shall not be liable  for any
defaults by Overlandlord or Oversublandlord. Neither Sublandlord nor Sublandlord
nor  Subtenant  shall take any action  that shall cause there to occur a default
under the terms of the Overleases (or either of them),  nor shall either fail to
take any action the failure of which shall cause there to occur such default. If
the Overleases (or either of them), nor shall either fail to take any action the
failure of which shall cause there to occur such default.  If the Overleases (or
either of them) shall be terminated for any reason during the term hereof,  then
and in that event this  Sublease  shall  thereupon  automatically  terminate and
Sublandlord  shall have no liability to  Subtenant by reason  thereof.  Upon the
termination of this Sublease, whether by forfeiture, lapse of time or otherwise,
or upon the  termination of Subtenant's  right to possession,  Subtenant will at
once  surrender  and  deliver up the  Premises  in good  condition  and  repair,
reasonable  wear and tear  excepted.  Sublandlord  and Subtenant  shall promptly
deliver  to the other any and all  notices  received  from the  Overlandlord  or
Oversublandlord  or their agents that affect the other's  rights or  obligations
under the Overleases (or either of them) or this Sublease.

     6.2.  This  Sublease is subject to, and  Subtenant  accepts  this  Sublease
subject to, any  amendments and  supplements  to the  Overleases  hereafter made
between the parties  thereto,  provided that any such amendment or supplement to
the Overleases (or either of them) will not prevent or adversely  affect the use
by  Subtenant  of the Premises in  accordance  with the terms of this  Sublease,
increase the obligations of Subtenant or decrease its rights under the Sublease,
or in any other way materially adversely affect Subtenant.

     6.3. This Sublease is subject and  subordinate to the Overleases and to all
ground or  underlying  leases  and to all  mortgages  that may now or  hereafter
affect such leases or the real  property of which the Premises  are a part,  and
all  renewals,  modifications,   replacements  and  extensions  of  any  of  the
foregoing.  This Section 6.3 shall be self-operative,  and no further instrument
of subordination  shall be required.  To confirm such  subordination,  Subtenant
shall execute promptly any certificate that Sublandlord may request.


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     7. CONDITION OF PREMISES.

     Subtenant  agrees  to  take  the  Premises  "as  is."  Notwithstanding  the
foregoing,  if a duly  authorized  regulatory  authority  or court of  competent
jurisdiction  shall hereafter  determine that the Premises  violate the terms of
the Americans With Disabilities Act (the "ADA"), and that such violation existed
prior to the Sublease  Commencement Date, then the cost of abating the violation
shall be borne by Sublandlord; provided, further, that if such violation results
from any  alteration  or  improvement  of the  Premises  performed  by or at the
direction of Subtenant, then the cost of abating the violation shall be borne by
Subtenant.

     8. USE OF PREMISES.

     Subtenant  agrees that the Premises  shall be occupied  only as  executive,
administrative  and general offices for Subtenant's  business  including  server
room, technical development,  sales and marketing and administrative  functions,
and such other additional use consistent with the Overlease.

     9. CONSENT OF OVERLANDLORD AND OVERSUBLANDLORD.

     9.1 This Sublease is conditioned  upon the consent  thereto by Overlandlord
and the Oversublandlord (collectively, the "Overlandlords"), which consent shall
be evidenced by Overlandlords'  signatures  appended hereto or separate consents
in the form utilized by  Overlandlords  for such  purposes.  Subtenant  shall be
solely  responsible  for  any  fees  or  charges  imposed  by  Overlandlords  in
connection with the obtaining of such consent.  Provided  Overlandlords' consent
does  not  materially  affect  the  terms  of  this  Sublease,  Subtenant  shall
immediately  execute any documents requested by Overlandlords in order to obtain
Overlandlords'  approval;  and, in the event such  documents  are not signed and
returned by Subtenant within five (5) days of receipt, Subtenant hereby appoints
Sublandlord as its attorney-in-fact  and authorizes  Sublandlord to execute same
on Subtenant's behalf.

     9.2  Sublandlord  makes  no   representation   with  respect  to  obtaining
Overlandlords'  approval of this Sublease  and, in the event that  Overlandlords
(or either of them) notify  Sublandlord that  Overlandlords  (or either of them)
will not give such  approval,  Sublandlord  will so notify  Subtenant  and, upon
receipt of such  notification by Sublandlord of the disapproval by Overlandlords
(or  either  of  them),  this  Sublease  shall be deemed to be null and void and
without force or effect,  and  Sublandlord  and Subtenant  shall have no further
obligations or liabilities to the other with respect to this Sublease.

     9.3 Except as  otherwise  specifically  provided  herein,  wherever in this
Sublease  Subtenant  is required to obtain  Sublandlord's  consent or  approval,
Subtenant  understands  that  Sublandlord  may be required  to first  obtain the
consent or approval of  Overlandlord  and/or  Oversublandlord.  If  Overlandlord
and/or Oversublandlord should refuse such consent or approval, Sublandlord shall
be released of any  obligation to grant its consent or approval,  whether or not
such refusal, in Subtenant's opinion, is arbitrary or unreasonable.


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     10. DEFAULT.

     10.1  Subtenant  acknowledges  that  the  services  to be  rendered  to the
Premises are not to be rendered by  Overlandlord.  Anything in this  Sublease to
the contrary notwithstanding,  if there exists a breach by Sublandlord of any of
its obligations under this Sublease and, concurrently, a corresponding breach by
Overlandlord and/or  Oversublandlord under the Overlease or Oversublease exists,
then,  and in such event,  Subtenant's  sole remedy  against  Sublandlord in the
event of any breach of  obligations  under this  Sublease  shall be the right to
pursue  a  claim   in  the  name  of   Sublandlord   against   Overlandlord   or
Oversublandlord  (as the case may be), and  Sublandlord  agrees that it will, at
Subtenant's expense, cooperate with Subtenant in the pursuit of such claim.

     10.2 Anything  contained in any provisions of this Sublease to the contrary
notwithstanding,  Subtenant agrees, with respect to the Premises, to comply with
and remedy any default claimed by Overlandlord and/or Oversublandlord and caused
by  Subtenant,  within the period  allowed to  Sublandlord  as tenant  under the
Overlease or the  Oversublease  (as the case may be) even if such time period is
shorter than the period  otherwise  allowed in the Overlease or the Oversublease
(as the case may be), due to the fact that notice of default from Sublandlord to
Subtenant is given after the  corresponding  notice of default from Overlandlord
and/or Oversublandlord. Sublandlord agrees to forward to Subtenant, upon receipt
thereof by Sublandlord, a copy of each notice of default received by Sublandlord
in its capacity as tenant under the Overlease and/or the Oversublease. Subtenant
agrees to forward to Sublandlord,  upon receipt  thereof,  copies of any notices
received  by  Subtenant   with  respect  to  the  Premises  from   Overlandlord,
Oversublandlord or from any governmental authorities.

     10.3 If and  whenever  there  shall  occur  any  event of  default  of this
Sublease,  Sublandlord  may, at Sublandlord's  option,  in addition to any other
remedy of right given under the Overlease or the  Oversublease  or by the law or
equity, do any one or more of the following:

          (a)  Terminate  this  Sublease,   in  which  event   Subtenant   shall
     immediately surrender possession of the Premise to Sublandlord;

          (b) Terminate  Subtenant's  right to possession of the Premises  under
     this Sublease without terminating the Sublease itself, by written notice to
     Subtenant,  in which event Subtenant shall immediately surrender possession
     of the Premises to Sublandlord;

          (c) Enter upon the Premises by force if necessary without being liable
     for  prosecution  or any  claim  for  damages  therefore,  and do  whatever
     Subtenant  is  obligated  to do  under  the  terms  of this  Sublease;  and
     Subtenant  agrees to  reimburse  Sublandlord  on demand  for any  direct or
     indirect  expense that  Sublandlord,  Oversublandlord  or Overlandlord  may
     incur in thus effecting compliance with Subtenant's  obligations under this
     Sublease, and Subtenant further agrees that Sublandlord shall not be liable
     for any damages resulting to Subtenant from such action.


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     10.4 It is hereby  expressly  stipulated by Sublandlord  and Subtenant that
any of the above listed actions, including,  without limitation,  termination of
this Sublease,  termination of Subtenant's  right to possession,  and reentry by
Sublandlord,  will not affect the  obligations  of Subtenant  for the  unexpired
Sublease Term,  including the  obligations to pay unaccrued  monthly rentals and
other  charges  provided  in this  Sublease  for the  remaining  portion  of the
Sublease Term.  Sublandlord is entitled to the same remedies as Overlandlord has
under the Overlease in addition to the above.

     11. SUBLANDLORD REPRESENTATION.

     Sublandlord  represents  (a) that it is the holder of the  interest  of the
Subtenant under the Oversublease, and (b) that the Oversublease is in full force
and effect and no default exists under the Oversublease.

     12. BROKERS.

     Each party hereto  covenants,  represents and warrants to the other that it
has had no dealings  or  communications  with any broker or agent in  connection
with the  consummation  of this  Sublease  other than the brokers  identified in
Section  1.1 (s),  above,  and each  party  covenants  and  agrees to pay,  hold
harmless  and  indemnify  the other from and against  any and all cost,  expense
(including  reasonable  attorneys'  fees)  or  liability  for any  compensation,
commissions or charges claimed by any other broker or agent with respect to this
Sublease or the negotiation thereof.

     13. OPERATING EXPENSES/TAXES.

     13.1 All charges for standard  Operating  Expenses and Property  Taxes,  as
defined in the  Overlease,  incurred  during normal  business hours for the Base
Year set forth in Section 1.1 (r), above,  shall be included in the Base Monthly
Rent herein.

     13.2 Subtenant shall pay to Sublandlord  Subtenant's  Proportional Share of
increases  above the Base Year in Operating  Expenses and Property  Taxes passed
through  to  Sublandlord  pursuant  to  the  terms  of  the  Oversublease.  Upon
Sublandlord's receipt of Oversublandlord's statement setting forth the amount of
Sublandlord's share of Operating Expenses and Property Taxes,  Sublandlord shall
prepare and deliver to Subtenant a statement  setting forth the  calculation  of
Subtenant's  Proportional Share of increase above the Base Year. Subtenant shall
pay, as additional  rent, the amount set forth in said statement within ten (10)
days of Subtenant's receipt thereof.

     14. ALTERATIONS.

     In the event Subtenant is permitted to perform  alterations in the Premises
hereunder, Subtenant may make no changes, alterations,  additions,  improvements
or decorations in, to or about the Premises  without  submitting  detailed plans
and  construction  schedules to Sublandlord  and receiving  Sublandlord's  prior
written  consent to such plans.  Subtenant  shall make no changes,  alterations,
additions,  improvements  or decorations  that would result in  Overlandlord  or
Oversublandlord charging Sublandlord for the cost of same, including any removal
costs  associated  therewith,  and  Subtenant  shall  comply  with  all laws and
regulations relating to such construction, including, but


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not  limited  to,  receipt  of  certificates  of  occupancy,   permits  and  ADA
requirements,  and  shall be  responsible  for all costs  associated  therewith.
Sublandlord may impose reasonable  guidelines as may be necessary to protect its
occupancy  and rights  provided in the  Overlease  and  Oversublease,  including
placing  reasonable  restrictions  on times  when  certain  types of work may be
performed in order to prevent undue  intrusion and noise to Sublandlord or other
tenants in the building.

     15. SECURITY DEPOSIT.

     15.1 As security for the faithful  performance  and observance by Subtenant
of the terms, provisions,  covenants and conditions of this Sublease,  Subtenant
is simultaneously  herewith  delivering to Sublandlord a security deposit in the
amount set forth in Section 1.1 (p) (the "Security Deposit").  In the event that
Sublandlord  applies any portion of the Security Deposit in respect of a default
by Subtenant, Subtenant shall forthwith restore the amount so applied so that at
all times the amount of the Security Deposit shall be not less than the security
required to be maintained from time to time.  Sublandlord may apply the whole or
any part of the Security  Deposit to the extent  required for the payment of any
sum as to which  Subtenant is in default,  or for any sum that  Sublandlord  may
expend or may be required to expend by reason of Subtenant's default.

     15.2 In the event that Subtenant shall fully and faithfully comply with all
of the terms,  provisions,  covenants  and  conditions  of this  Sublease,  that
portion of the  Security  Deposit  not used or applied by  Sublandlord  shall be
returned to Subtenant within thirty (30) days after the Sublease Expiration Date
and  after  delivery  of  entire  possession  of the  Premises  to  Sublandlord,
Oversublandlord or Overlandlord, as the case may be.

     16. PARKING.

     16.1  Subtenant  shall be entitled to three and four tenths  (3.4)  parking
spaces  (free of charge) per one thousand  (1,000)  Rentable  Square  Footage of
Premises.

     16.2  Sublandlord  has  installed  data and phone  cabling  throughout  the
Premises.  Subtenant shall have the right,  but not the  obligation,  to use any
such wiring during the Sublease Term.

     16.3 Subtenant  shall have the right to install  reasonable  signage in and
about  the  Premises   subject  to  the  reasonable   consent  of  Overlandlord,
Oversublandlord and Sublandlord, and further subject to all applicable law.

     16.4  Subject  to  the  terms  of  the  Overlease  and  the   Oversublease,
Subtenant's  authorized  employees shall have access to the Premises twenty-four
(24) hours per day, three hundred sixty-five (365) days per year.

     17. QUIET ENJOYMENT.

     17.1. So long as the Subtenant pays all of the rent and additional rent due
under this Sublease and performs all of Subtenant's other obligations hereunder,
Subtenant


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shall  peacefully  and  quietly,  have,  hold and enjoy the  Premises,  subject,
however,  to the terms,  provisions  and  obligations  of this  Sublease and the
Overlease.

     17.2 In the event Subtenant does not completely  vacate the Premises by the
Sublease  Expiration  Date or earlier  termination of this  Sublease,  Subtenant
shall indemnify and hold harmless Sublandlord in respect of any and all holdover
charges or  penalties  imposed  under the  Overlease  or the  Oversublease  upon
Sublandlord  in  respect  of the  Premises  and in respect of any and all costs,
liabilities or expenses  (including  attorney's fees) suffered by Sublandlord in
respect of same, as and when such costs,  liabilities  or expenses are incurred.
In this regards, Subtenant shall, if requested by Sublandlord,  in Sublandlord's
sole discretion,  defend  Sublandlord  against any action or proceeding  brought
against Sublandlord that arises out of said holdover.

     18. NO WAIVER.

     The failure of  Sublandlord  to seek redress for violation of, or to insist
upon the strict performance of, any covenant or condition of this Sublease or of
any of the Rules and Regulations set forth or hereafter  adopted by Sublandlord,
shall not prevent a  subsequent  act that would have  originally  constituted  a
violation  from  having all the force and effect of an original  violation.  The
receipt by  Sublandlord  of rent with knowledge of the breach of any covenant of
this  Sublease  shall not be deemed a waiver of such breach and no  provision of
this  Sublease  shall be deemed to have been waived by  Sublandlord  unless such
waiver be in writing, signed by Sublandlord.  No payment by Subtenant or receipt
by Sublandlord of a lesser amount than the monthly rent herein  stipulated shall
be deemed to be other  than on  account of the  earliest  stipulated  Base Rent,
additional  rent or other charge,  nor shall any endorsement or statement on any
check or any  letter  accompanying  any check or  payment  accept  such check or
payment without prejudice to Sublandlord's  right to recover the balance of such
Base Rent,  additional rent or other charge,  or pursue any other remedy in this
Sublease provided.  No act or thing done by Sublandlord or Sublandlord's  agents
during the term hereby  demised  shall be deemed an acceptance of a surrender of
the demised  premises,  and no agreement to accept such surrender shall be valid
unless  in  writing,  signed by  Sublandlord.  No  employee  of  Sublandlord  or
Sublandlord's  agent  shall  have any  power to accept  the keys of the  demised
premises prior to the  termination of the Sublease,  and the delivery of keys to
any such agent or employee shall not operate as a termination of the Sublease or
a surrender of the demised premises.

     19. NOTICES.

     19.1 Any notice,  demand or  communication  which,  under the terms of this
Sublease or under any statue or  municipal  regulation,  must or may be given or
made by the parties  hereto shall be in writing and given or made by mailing the
same by registered or certified mail, return receipt  requested,  to the address
and person designated in Sections 1.1(a) and (c), herein.

     19.2 Either  party,  however,  may  designate  such new or other address to
which such notices, demands or communications thereafter shall be given, made or
mailed by notice  (given in the  manner  prescribed  herein).  Any such  notice,
demand or communication  shall be deemed given or served, as the case may be, on
the date of the


                                 Page 10 of 12
<PAGE>

posting thereof. In the event Subtenant's address is not set forth above, notice
to Subtenant shall be deemed sufficient if sent to the Premises.

     20. MISCELLANEOUS.

     20.1 Where  applicable,  Subtenant  shall be responsible for all additional
costs  incurred  as a result of this  Sublease,  including,  but not limited to,
security cards, keys and parking cards.

     20.2 This Sublease may not be changed  orally,  but only by an agreement in
writing  signed by the party  against whom  enforcement  of any waiver,  change,
modification or discharge is sought.

     20.3 This Sublease shall not be binding upon  Sublandlord  unless and until
it is signed by Sublandlord and delivered to Subtenant.  This Section 20.3 shall
be not deemed to modify the provisions of Section 10, hereof.

     20.4 This Sublease  constitutes the entire  agreement  between the parties,
and all representations and understandings have been merged herein.

     20.5 This Sublease shall inure to the benefit of all of the parties hereto,
their successors and (subject to the provisions hereof) their assigns.


                     (The signature page follows this page.)


                                 Page 11 of 12
<PAGE>

IN WITNESS  WHERE OF, the parties have hereunto set their hands and seals on the
day and year first above written.

                                             Metro PCS, California/Florida
                                             Inc. Subtenant


                                             By:   /s/ David Rotenberg
                                                   David Rotenberg
                                                   Vice President Of Finance
                                             Date: 7/16/01


                                             TCSI CORPORATION, Sublandlord


                                             By:   /s/ Kenneth Elmer
                                                   Kenneth Elmer
                                                   Chief Financial Officer
                                             Date: 7/17/01