CENTRAL OFFICE CODE 555 Author David Bench NCE

CENTRAL OFFICE CODE “ 555” Author: David Bench, NCE Company: Nortel Networks Date: July 17, 2001 Contact: 919 991 -7362 dbench@nortelnetworks. com Past participant of the ATIS/ICCF Past Moderator of the ATIS/ NIIF David H. Bench – Nortel Networks 555 Line Numbers - 1

PURPOSE OF 555? • Created by AT&T Network Planning • Purpose for completion of Directory Assistance • Used in US and Canada • All US and Canadian Area Codes have 555 working - Code 555 assigned to Area Code DA Center - Area Code plus 555 has a defined CLLI, Rate Center & Wire Center • Area Code plus 555 completes to DA - Trunk Side Access & DA Billing No line side connections David H. Bench – Nortel Networks 555 Line Numbers - 2

OTHER USES OF 555 NUMBERS • Inter. LATA Carrier check number: 1+700 555 -4141 - 700 takes caller to IXC network • Local Service Provider check number: 555 -0055 - Can’t be made to work • Given to the Entertainment Industry for use in movies and television. (555 -0100 – 555 -0199) No other CO code has line numbers assigned by NANPA David H. Bench – Nortel Networks 555 Line Numbers - 3

INDUSTRY ISSUE ON 555 Opening of the 555 numbering resource (Line Numbers) • ICCF Issue in 1994 - by Telco Planning • Number Assignment Guidelines developed 1996 - NANPA began assignment in 1996 • Interconnection arrangements developed 1996 - Needs Technical Requirements & Development Area Code + 555 Cannot Complete to Multiple SPs David H. Bench – Nortel Networks 555 Line Numbers - 4

WHAT WENT WRONG? • Classic case of the cart before the horse syndrome. • Assignment guidelines and number assignment occurred before the technology was put into place. • Holders of 555 Code would need to fund switch development. David H. Bench – Nortel Networks 555 Line Numbers - 5

TECHNOLOGY CHANGES SINCE 1996 • Local Number Portability - Not universally deployed - Only deployed in certain Rate Centers - No geographic portability • Advanced Intelligent Network (AIN) - Not universally deployed - Data base routing number would use another numbering resource. David H. Bench – Nortel Networks 555 Line Numbers - 6

HOW CAN THE INDUSTRY MAKE IT WORK? • It is technically possible to make it work • Who develops the technical specifications? • Who develops switch technology? • Who pays for deployment of the capability? 555 Line Number advocates want “someone else” to pay the bills. David H. Bench – Nortel Networks 555 Line Numbers - 7