November 11, 1997

Team,

The following is the final version of the update letter that went out to Bill Celio today.

Thanks, to Jim Tamplin and Donna Navickas for clarification feedback.

Larry

November 11, 1997

Bill Celio

MPSC Staff

P. O. Box 30221

Michigan Public Services Commission

6545 Mercantile Way

Lansing, Michigan 48909

Re: Detroit MSA LNP General Availability

Dear Mr. Celio:

The following is an update of the Local Number Portability (LNP) testing plan and general availability (GA) date for the Detroit MSA.

General Availability is when Service Providers are capable of porting local telephone numbers. All industry participants (Ameritech, AT&T, MCI, and TCG) completed LNP testing, ahead of schedule, on October 23, 1997. The connectivity and network interface stability issues between the participating Service Providers’ local NPAC interface systems and Lockheed Martin’s NPAC SMS have been resolved. These connectivity

issues affected the Chicago and Detroit GA date which was previously re-scheduled to November 3, 1997.

As you already know, Ameritech has filed a cost recovery tariff in Illinois that potentially delays the GA date for Chicago until November 24, 1997 (pending Illinois Commerce Commission approval). However, Detroit’s GA date has been re-scheduled to December 15, 1997.

The reason for this additional delay of LNP implementation in Detroit is the NPA Split processing of ported numbers. The required processes for this activity had not been clearly defined in the NPAC Functional Requirement Specification (FRS) and Interoperable Interface Specifications (IIS). This created various implementations by the vendors resulting in functional incompatibility. This issue was brought to the attention of the North American Numbering Council Technical and Operations (NANC T&O) Task Force. The Task Force provided more definitive system and interface requirements which required modifications on both local vendor and NPAC SMS products. The Mid-West NPAC SMS and local vendors will be able to deliver and load these changes on December 3, 1997. The Service Provider Test Team will require approximately 12 working days to test and make any relevant corrections to this new NPAC release.

As you know, the Detroit 313 Area Code is scheduled to split to 734, with permissive dialing starting on December 13, 1997. Industry team members agree that we could potentially risk service to newly ported customers if the new software was not completely tested prior to December 13, 1997. Thus we have re-scheduled the GA to December 15, 1997. I will keep you informed as we get closer to providing LNP in Detroit.

If there are any questions regarding this update, feel free to call me at (312) 230-6253.

cc: Terry Appenzeller, Ameritech

Bob Reynolds, Ameritech