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                                                                   Exhibit 10.60

                          AMENDMENT TO DEED OF LEASE
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     THIS AMENDMENT TO DEED OF LEASE ("Amendment") made and entered into this
18th day of November, 1999, by and between AMES CENTER, L.C., a Virginia
limited liability company, hereinafter called "Lessor", and CAIS, INC., a
Virginia corporation. hereinafter called "Lessee."


                             W I T N E S S E T H:

     WHEREAS, on the 10th day of August, 1999, the Lessor and Lessee entered
into a Deed of Lease ("Lease") for the lease of the fourth floor and fifth floor
("Fourth Floor Demised Premises and Fifth Floor Demised Premises") in the
building located at 1820 N. Fort Myer Drive, Arlington, Virginia (the
"Building"); and

     WHEREAS, the Lessor desires to lease to the Lessee and the Lessee desires
to lease from the Lessor Suite No. 700 on the seventh floor ("Seventh Floor
Demised Premises") in the Building upon the terms and conditions hereinafter set
forth; and

     WHEREAS, the parties are desirous of making certain modifications to the
Lease as hereinafter set forth;

     NOW, THEREFORE, FURTHER WITNESSETH, that for and in consideration of the
rents, mutual covenants and agreements hereinafter set forth, the parties hereto
agree that the Lease be and the same is hereby amended as follows:

     1.  Section 1, DEMISED PREMISES.  After the date hereof, this Section is
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modified to provide that the Demised Premises shall consist of Suite No. 400 on
the Fourth Floor Demised Premises, Suite No. 500 on the Fifth Floor Demises
Premises, and Suite No. 700 on the Seventh Floor Demises Premises.  The Demised
Premises shall contain approximately 42,348 square feet (approximately 14,116
square feet per floor) as outlined on the floor plan attached hereto and made a
part hereof as Exhibit A is determined in accordance with GWCAR standard method
of measurement (revised June 1995).

     2.  Section 2, TERM.  The Term for the Seventh Floor Demised Premises shall
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commence on the 1st day of January 2000 (hereinafter called the "Seventh Floor
Commencement Date") and shall expire on the 28th day of February 2010 (the
"Initial Term").

          In the event Lessor is unable to deliver possession of the Seventh
Floor Demises Premises to Lessee by the Seventh Floor Commencement Date, with
all of the Lessor's Work therein substantially completed due to causes beyond
the control of the Lessor, Lessor, its
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agents and employees, shall not be liable or responsible for any claims, damages
or liabilities arising in connection therewith or by reasons thereof, nor shall
Lessee be excused or released from this Lease, because of Lessor's inability to
deliver the Seventh Floor Demises Premises.

     3.   Section 4, RENT.
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          a.   Irrespective of any provision of this Amendment or the Lease,
Lessee's obligation to pay rent shall begin on January 1, 2000, and shall
continue to remain an obligation of Lessee until completely satisfied.

          b.   The Monthly Rent for the Seventh Floor Demises Premises shall be
Twenty-Nine Thousand Nine Hundred Ninety-Six and 50/100 Dollars ($29,996.50) per
month and shall commence on the Seventh Floor Commencement Date and the total
Monthly Rent for the Fourth, Fifth and Seventh Floor Demises Premises shall be
Eighty-Nine Thousand Nine Hundred Eighty-Nine and 50/100 Dollars ($89,989.50)
per month.

          c.   Commencing on January 1, 2001, and each twelve (12) months during
the Initial Term and Extended Term, if applicable, the Monthly Rent for the
Seventh Floor Demised Premises shall be increased by a sum equal to three
percent (3%) of the Monthly Rental during the preceding twelve (12) month lease
period.

          d.   Lessee shall pay the first installment of Monthly Rent for the
Seventh Floor Demised Premises concurrent with the execution of this Lease.

     4.   Section 5, SECURITY DEPOSIT.  Upon the execution of this Amendment,
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Lessee shall deposit with Lessor cash or an appropriate letter of credit in the
amount of ONE HUNDRED SEVENTH-FIVE THOUSAND AND 00/100 DOLLARS ($175,000.00)
("Letter of Credit").  In the event the Lessee is not in Default under the terms
of this Lease, after notice to the Lessee and the expiration of the applicable
cure period, Lessee shall have the right to reduce the amount of the said Letter
of Credit as of January 1, 2001, and the remainder of the Term, to THIRTY
THOUSAND AND 00/100 DOLLARS ($30,000.00).  All other provisions of Section 5 of
the Lease shall be applicable to the Security Deposit for the Seventh Floor
Demised Premises.

     5.   Section 7, RENTAL ESCALATIONS FOR INCREASE IN EXPENSES.
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          d.   Add the following to the second paragraph thereof: "From and
after the Seventh Floor Commencement Date, the Lessee's share of the increase
shall be 26.175% of the total increase, which share shall be increased if the
Demised Premises shall be increased during the Term or any renewal hereof."
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     6.   Section 11, REAL ESTATE AND OTHER TAXES OR ASSESSMENTS.
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          c.   Amend the second paragraph by adding the following at the end:
"Lessee's share, as aforesaid, shall be 26.175% of the total increase from and
after the Seventh Floor Commencement Date."

               Amend the third paragraph by inserting the following after the
word "refund" in the second sentence thereof: "which percentage shall increase
to 26.175% from and after the Seventh Floor Commencement Date."

     7.   Section 66, FIRST RIGHT TO LEASE.  The parties agree that the Lessee's
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right to lease any space on the 1st and 2nd floors of the Building, as set forth
in Section 66, is hereby terminated.

     8.   The provisions contained within Section 65 of the Lease pertaining to
the provision by Lessor of the Lessor's Allowance, the Lessor's Additional
Allowance and the Base Building Environment shall fully apply to the Seventh
Floor Demised Premises.  All remaining provisions of the Lease which apply to
the Fourth Floor Demised Premises and Fifth Floor Demised Premises shall be
fully applicable to the Seventh Floor Demised Premises, except to the extent
such provisions are inconsistent with the terms of this Amendment, in which
event the terms of this Amendment shall prevail.  The Lessor and the Lessee
agree that, with respect to the Fifth Floor Commencement Date, the Monthly Rent
shall commence as of March 1, 2000, irrespective of whether or not the Lessee
occupies the Fifth Floor Demised Premises prior to March 1, 2000.

     9.   Except as expressly set forth in this Amendment, all other terms,
conditions and provisions of the Lease shall remain in full force and effect.

     IN WITNESS WHEREOF, Lessor and Lessee have caused this Amendment to be
signed in their names by their duly authorized representatives and delivered as
their act and deed, intending to be legally bound by its terms and provisions.


                                   LESSOR:

                                   AMES CENTER, L.C.,
                                   a Virginia Limited Liability Company

                                   By:  SNELL CONSTRUCTION CORPORATION,
                                        Manager

                                   By: ________________________________(SEAL)
                                       Its:

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                                   LESSEE:
                                   CAIS, INC.



                                   By:______________________________(SEAL)
                                   Its:_____________________________

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