Exhibit 10.1.2

              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

Pursuant to Instruction 2 to Item 601 of Regulation S-K, NeuStar, Inc. has filed
an agreement with the Northeast Carrier Acquisition Company, LLC, which is one
of seven agreements that are substantially identical in all material respects
other than the parties to the agreements. North American Portability Management,
LLC succeeded to the interests of Northeast Carrier Acquisition Company, LLC and
each of the other entities listed below. The following list identifies the other
parties to the six agreements that have been omitted pursuant to Instruction 2
to Item 601:

•   LNP, LLC (Midwest)   •   Southwest Region Portability Company, LLC   •  
Western Region Telephone Number Portability, LLC   •   Southeast Number
Portability Administration Company, LLC   •   Mid-Atlantic Carrier Acquisition
Company, LLC   •   West Coast Portability Services, LLC

[Graphic Omitted: NeuStar Logo]
STATEMENT OF WORK NO. 51
UNDER
CONTRACTOR SERVICES AGREEMENT
FOR
NUMBER PORTABILITY ADMINISTRATION CENTER / SERVICE
MANAGEMENT SYSTEM
MODIFICATION TO EXHIBIT G AND EXHIBIT N
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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

STATEMENT OF WORK NO. 51
UNDER
CONTRACTOR SERVICES AGREEMENT
FOR
NUMBER PORTABILITY ADMINISTRATION CENTER/SERVICE
MANAGEMENT SYSTEM
Modification to Exhibit G and Exhibit N

1.0   PARTIES

This Statement of Work (“SOW”) is entered into pursuant to Article 30 of, and
upon execution shall be a part of, the Contractor Services Agreements for Number
Portability Administration Center/Service Management System, as amended and in
effect immediately prior to the Statement of Work Effective Date (each such
agreement referred to individually as the “Master Agreement” and collectively as
the “Master Agreements”), by and between NeuStar, Inc., a Delaware corporation
(“Contractor”), and the North American Portability Management LLC, a Delaware
limited liability company (the “Customer”), as the successor in interest to and
on behalf of the Northeast Carrier Acquisition Company, LLC (the “Subscribing
Customer”).

2.0   EFFECTIVENESS AND DEFINED TERMS

This Statement of Work shall be effective in the separate United States Service
Area known as the Northeast Service Area (referred to in this SOW as “this
Service Area”) as of the 1st day of January, 2006 (the “Statement of Work
Effective Date”), conditioned upon execution by Contractor and Customer on
behalf of all the limited liability companies listed below for the separate
United States Service Areas (the “Subscribing Customers”).

  •   LNP, LLC (Midwest)     •   Mid-Atlantic Carrier Acquisition Company, LLC  
  •   Northeast Carrier Acquisition Company, LLC     •   Southeast Number
Portability Administration Company, LLC     •   Southwest Region Portability
Company, LLC     •   West Coast Portability Services, LLC     •   Western Region
Telephone Number Portability, LLC

The number in the upper left-hand corner refers to this Statement of Work.
Capitalized terms used herein without definition or which do not specifically
reference another agreement shall have the meanings as defined in the Master
Agreements.

3.0   CONSIDERATION RECITAL

In consideration of the terms and conditions set forth in this Statement of
Work, and for other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged,
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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

Contractor and Customer agree as set forth in this Statement of Work.

4.0   MODIFICATIONS TO EXHIBIT G   4.1   Background

Statement of Work No. 49, Revision 1, provided for the incorporation of NANC
Change Order 393 (NPAC Performance Requirements) into Release 3.3 of the
NPAC/SMS Software. Because the current Functional Requirements Specification
(“FRS”) performance requirements do not fully account for sustained and peak
performance requirements, NANC 393 was intended to provide NPAC/SMS performance
requirements to account for sustained, peak, and total bandwidth numbers. These
new numbers represent a clarification of the measurement of NPAC performance.
These changes are reflected in the FRS with the deletion of assumptions AR6-1
and AR6-2, the addition of assumptions AR6-3, AR6-4, AR6-5, and AR6-6, the
deletion of requirement R6-29.1, the updating of requirements R6-28.1, R6-28.2,
and R6-29.2, and the addition of requirements RR6-107, RR6-108, and RR6-109. The
updated NPAC performance requirements, as specified in the revised FRS, affect
Exhibit G under the Master Agreement, which exhibit must be updated to reflect
the aforementioned changes. Accordingly, Contractor and Customer agreed in
Statement of Work 49, Revision 1, to make the appropriate revisions to these
exhibits prior to the Anticipated Delivery Date of Release 3.3. In addition to
the implementation of Release 3.3 (under SOW49, as amended) in all United States
Service Areas, currently scheduled to be completed April 9, 2006, the following
activities must be completed before the changes to Exhibit G set forth in this
SOW can be implemented:

  1.   Customer executes this SOW51 on behalf of all Subscribing Customers.    
2.   Contractor revised the SLR Methods & Procedures document to reflect the
changes to Exhibit G as set forth herein.     3.   Customer and Contractor
approve GEP Metrics Document revised to reflect the changes to Exhibit G as set
forth herein.     4.   GEP Auditor revises GEP Audit Plan to reflect the changes
in the GEP Metrics Document as set forth above.

Upon the completion of all the activities set forth above and the implementation
of Release 3.3 in all Service Areas, the changes to SLR5 set forth below in
Section 4.2 and the changes to SLR6 set forth in Section 4.3 shall take effect
on the date agreed by Contractor and Customer, and confirmed by the GEP Auditor.

4.2   SLR 5 Change

As a result of the update to NPAC performance requirement R6-28.1 and the
addition of performance requirement RR6-107 , SLR5 — SOA to NPAC Interface
Transaction Rates (Customer) of Exhibit G (Service Level Requirements) under the
Master Agreement applicable in this Service Area is hereby amended by deleting
in its entirety the “Service Commitment Level” entry for SLR 5 — SOA to NPAC
Interface Transaction Rates (Customer) in this Service Area and replacing it
with the following
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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

To the extent there is sufficient load, maintain, for 95% of the CMIP
transactions, a rate of 4 CMIP transactions per second (sustained) for each SOA
to NPAC SMS interface association; however, this interface requirement does not
apply when there are at least 40 CMIP transactions per second (sustained) for a
single NPAC SMS region. Neither criterion applies if throughput is impacted by
delays caused by Users.

4.3   SLR 6 Change

As a result of the deletion of requirement R6-29.1 and the update to NPAC
performance requirement R6-29.2 and introduction of performance requirements
RR6-108 and RR6-109, the “Service Commitment Level” entry for SLR 6 – NPAC to
LSMS Interface Transaction Rates (Customer) in this Service Area is deleted in
its entirety and replaced with the following:
To the extent there is sufficient offered load, maintain, for 95% of the CMIP
transactions, a rate of 4 CMIP transactions per second (sustained) over each
NPAC SMS to Local SMS interface association; however, this interface requirement
does not apply when there are at least 156 CMIP transactions per second
(sustained) for a single NPAC SMS region. Neither criterion applies if
throughput is impacted by delays caused by Users.
In the event that the CMIP Interface Specification is changed, for purposes of
the foregoing computation, each CMIP transaction involved in a broadcast of an
SV will contain at least one (1) TN.

5.0   RESCISSION OF EXHIBIT N   5.1   Background

R6-29.1 and R6-29.2 formed the basis for the final milestone throughput goal of
25 TN’s per second under Exhibit N (System Performance Plan for NPAC SMS
Services). Contractor was required to demonstrate the achievement of each
milestone, both interim and final, in laboratory testing, which was defined as a
specified mix of range and individual transactions involving broadcasts to seven
LSMS’s. Exhibit N suspended SLR 6 – NPAC to LSMS Interface Transaction Rates
(Customer) until the 25 TN’s per second goal was achieved. The Contractor
represents that it has achieved well in excess of 25 TNs per second in
laboratory tests. As a result of the achievement of the 25 TN’s per second
milestone, the SLR6 suspension ought to be terminated by the terms of Exhibit N,
and therefore no update to Exhibit N is required as was otherwise referenced in
NANC 393 of SOW49, Revision 1. Contractor and Customer hereby agree that
Exhibit N is rescinded in its entirety.

5.2   Rescission of Exhibit N

As a result of the termination of the SLR6 suspension, Exhibit N (Systems
Performance Plan for NPAC/SMS Services) to the Master Agreement applicable in
this Service Area is hereby
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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

rescinded in its entirety.

6.0   APPLICABLE DOCUMENTS

The following internal documents are applicable to the changes contemplated
under this SOW:
None Functional Requirements Specifications
None Requirements Traceability Matrix
None System Design
None Detailed Design
None Integration Test Plan
None System Test Plan
None NPAC Software Development Process Plan
None User Documentation

7.0   IMPACTS ON MASTER AGREEMENT

None Master Agreement
None Exhibit B Functional Requirements Specification
None Exhibit C Interoperable Interface Specification
None Exhibit E Pricing Schedules
None Exhibit F Project Plan and Test Schedule
þ Exhibit G Service Level Requirements
None Exhibit H Reporting and Monitoring Requirements
None Exhibit J User Agreement Form
None Exhibit K External Design
None Exhibit L Infrastructure/Hardware
None Exhibit M Software Escrow Agreement
þ Exhibit N System Performance Plan for NPAC/SMS Services
None Disaster Recovery
None Back Up Plans
þ Gateway Evaluation Process (Article 32 of Master Agreement)

8.0   COMPENSATION AND PAYMENT   8.1   Allocable Charges

Customer represents that it is executing this SOW on behalf of each of the
Subscribing Customer’s Allocated Payors, as that term is defined in the Master
Agreement, as amended by SOW42.

9.0   MISCELLANEOUS

9.1   Except as specifically modified and amended hereby, all the provisions of
the Master

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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

Agreement and the User Agreements entered into with respect thereto, and all
exhibits and schedules thereto, shall remain unaltered and in full force and
effect in accordance with their terms. From and after the Statement of Work
Effective Date hereof, any reference in the Master Agreement to itself and any
Article, Section or subsections thereof or to any Exhibit thereto, or in any
User Agreement to itself or to the Master Agreement and applicable to any time
from and after the Statement of Work Effective Date hereof, shall be deemed to
be a reference to such agreement, Article, Section, subsection or Exhibit, as
modified and amended by this. From and after the Statement of Work Effective
Date, Statement of Work shall be a part of the Master Agreement, including its
Exhibits, and, as such, shall be subject to the terms and conditions therein.
Each of the respective Master Agreements with respect to separate Service Areas
remains an independent agreement regarding the rights and obligations of each of
the Parties thereto with respect to such Service Area, and neither this
Statement of Work nor any other instrument shall join or merge any Master
Agreement with any other, except by the express written agreement of the Parties
thereto.
9.2 This Statement of Work may be executed in two or more counterparts and by
different parties hereto in separate counterparts, with the same effect as if
all parties had signed the same document. All such counterparts shall be deemed
an original, shall be construed together and shall constitute one and the same
instrument.
9.3 If at any time hereafter a Customer, other than a Customer that is a party
hereto desires to become a party hereto, such Customer may become a party hereto
by executing a joinder agreeing to be bound by the terms and conditions of this
Statement of Work, as modified from time to time.
9.4 This Statement of Work is the joint work product of representatives of
Customer and Contractor; accordingly, in the event of ambiguities, no inferences
will be drawn against either party, including the party that drafted the
Agreement in its final form.
9.5 This Statement of Work sets forth the entire understanding between the
Parties with regard to the subject matter hereof and supercedes any prior or
contemporaneous agreement, discussions, negotiations or representations between
the Parties, whether written or oral, with respect thereto. The modifications,
amendments and price concessions made herein were negotiated together and
collectively, and each is made in consideration of all of the other terms
herein. All such modifications, amendments and price concessions are
interrelated and are dependent on each other. No separate, additional or
different consideration is contemplated with respect to the modifications,
amendments and price concessions herein.
[THIS SPACE INTENTIONALLY LEFT BLANK]
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              Amendment No. 51 (NE)       January 1, 2006
SOW:
  o No        
 
  þYes        

IN WITNESS WHEREOF, the undersigned have executed this Statement of Work:
CONTRACTOR: NeuStar, Inc.

         
By:
Its:
  /s/ Joe Franlin
 
Sr. VP Customer Relations     Date: 6/6/06    

CUSTOMER: North American Portability Management LLC, as successor in interest to
and on behalf of the Northeast Carrier Acquisition Company, LLC

         
By:
Its:
  /s/ Melvin Clay
 
Co-Chair     Date: May 23, 2006    
 
       
By:
Its:
  /s/ Suzanne Howard
 
Co-Chair     Date: 6/1/06    

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