CENTRAL OFFICE CODE

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CENTRAL OFFICE CODE 555
Author David Bench, NCE Company Nortel
Networks Date July 17, 2001 Contact 919
991-7362 dbench_at_nortelnetworks.com
Past participant of the ATIS/ICCF Past Moderator
of the ATIS/ NIIF
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PURPOSE OF 555?

• Created by ATT 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
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OTHER USES OF 555 NUMBERS

• InterLATA Carrier check number 1700 555-4141
• - 700 takes caller to IXC network
• Local Service Provider check number 555-0055
• - Cant 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
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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
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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.

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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.

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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.