Toll-free number portability

ACA fixed a November 2000 implementation date for the provision of local rate and freephone number portability. The industry established a body, Industry Number Management Services (INMS) Ltd, to allocate individual numbers and administer the centralised reference database of all allocated local rate and freephone numbers.[1]

Vanity numbers, such as phonewords or short 13- series shared-cost service numbers, are made available by auction.

United Kingdom numbers in the 0800 range (BT Freefone) first became portable in June 1997.[2] Previously, rival carriers used differing area codes, 0800 for BT Freefone and 0500 for Cable & Wireless Freecall numbers.

Germany, Netherlands, Sweden and Belgium also introduced portability schemes in the late 1990s.

In the original InWATS service, introduced in 1967, there was no number portability. Each exchange prefix in the +1-800 area code was assigned to a specific carrier in a specific region (for instance, +1-800-387 was Bell Canada in Toronto) and the numbers were brought to subscribers (usually large companies or governmental organisations) on special fixed-rate inbound trunks.

The system was redesigned in 1981 to use a database, the SMS/800 service management system, which could direct any toll-free number to any destination based on various conditions; number prefixes remained tied to specific carriers until a RespOrg (responsible organisation) structure was introduced in 1993 (US) and 1994 (Canada) to allow subscribers to change providers by providing a Letter of Authorisation (LOA) on company letterhead to their new provider authorising a number to be moved.[3]

TNAS Limited, a joint venture company owned by Telecom and Vodafone, operates the Toll Free Number Portability system. The TNAS System is a database for co-ordination of allocation and porting of toll-free numbers and is used by nine carriers.[4] A client may switch service providers, or a service provider switch host carriers, without a change in the published toll-free number.[5]

• Local number portability
• Mobile number portability
• Rufnummernportierung (in German)