Exhibit 10.1.20

Second Extension Amendment to the iDEN Infrastructure 5 Year Supply Agreement

SECOND EXTENSION AMENDMENT
TO THE
IDEN INFRASTRUCTURE 5 YEAR SUPPLY AGREEMENT

This Second Extension Amendment to the iDEN Infrastructure 5 Year Supply
Agreement (“Amendment”) is entered into this 14th day of December, 2004
(“Effective Date”) between MOTOROLA, INC., a Delaware corporation, by and
through its Global Telecom Solutions Sector, with offices at 1421 W. Shure
Drive, Arlington Heights, Illinois 60004 (“Motorola”), and, NEXTEL
COMMUNICATIONS, INC., a Delaware corporation, with offices at 2001 Edmund Halley
Drive, Reston, VA 20191 (“Nextel”);

WHEREAS, Motorola and Nextel previously entered into (i) the iDEN Infrastructure
5 Year Supply Agreement effective as of the 1st day of January, 1999; and
(ii) the Term Sheet for Subscriber Units and Services dated as of the 31st day
of December 2003;

WHEREAS, Motorola and Nextel previously entered into the Extension Amendment
dated March 16, 2004, and effective as of January 1, 2004, which extended the
term of the agreements described in (i) and (ii) of the foregoing recital
through the earlier of December 31, 2004 or execution of a new agreement (the
iDEN Infrastructure 5 Year Supply Agreement, as amended by the Extension
Amendment shall be referred to herein as the “Existing Agreement”; the Term
Sheet for Subscriber Units, as extended by the Extension Amendment shall be
referred to herein as the “Handset Term Sheet”);

WHEREAS, Motorola and Nextel previously entered into the 6:1 Interconnect
Resolution Agreement dated as of the 30th day of September, 2004, which amended
the terms of the Funding Model (attached as Exhibit A to the Extension
Amendment); and

WHEREAS, Motorola and Nextel wish to further extend the term of the Existing
Agreement through December 31, 2007.

WHEREAS, Motorola and Nextel intend that all terms, except as modified herein,
of the Existing Agreement (as amended by the Extension Amendment or other
amendments) shall remain in full force and effect.

NOW, THEREFORE, in consideration of the promises and mutual obligations
contained herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby mutually acknowledged, Motorola and Nextel agree
as follows:

1. General

Except as set forth herein, all capitalized terms not defined herein shall have
the meanings given to them in the Existing Agreement or the Handset Term Sheet,
as appropriate.

2. Modifications to Existing Agreement

Motorola and Nextel hereby agree as follows (all references are to sections in
the Existing Agreement).

a)   Section 28, Term, is hereby amended by substituting December 31, 2007 in
place of the date “December 31, 2004”.

b)   The date “December 31, 2004” which appears in Section 2(c) of the Extension
Amendment is hereby amended to read “December 31, 2007.”

c)   Section 4 of the Extension Amendment, entitled “Extension of the Handset
Term Sheet”, shall remain unmodified, and shall not (nor shall the Handset Term
Sheet referenced therein) be deemed modified, extended or otherwise affected by
any of the terms of this Amendment.

Motorola and Nextel Confidential Proprietary

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Second Extension Amendment to the iDEN Infrastructure 5 Year Supply Agreement

3. Entire Agreement

This Amendment and its Exhibits and the Existing Agreement constitute the entire
understanding between the Parties concerning the subject matter hereof and
supersede all prior discussions, agreements and representations, whether oral or
written and whether or not executed by Nextel and Motorola. No modification,
amendment or other change may be made to this Amendment unless reduced to
writing and executed by authorized representatives of both Parties.

IN WITNESS WHEREOF, Motorola and Nextel have entered into this Amendment as of
the Effective Date first written above.

                              MOTOROLA, INC.
Global Telecom Solutions Sector       NEXTEL COMMUNICATIONS, INC.  
 
                           
By:
  /s/ Charles F. Wright       By:   /s/ Brian Meadows            

                           
Name:
  Charles F. Wright       Name:   Brian Meadows            
Title:
  Senior Vice President       Title:   Senior Vice President            

Motorola and Nextel Confidential Proprietary

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