Numbering

Information about the central database for US toll free number management.

http://www.sms800.com/

PageRank: 0/10

Detailed information on the history and current developments in North American NPA allocations.

http://www.areacode-info.com/

PageRank: 0/10

A collection of all international numbering plans in the world. Some features require a paid subscription.

http://www.numberingplans.com/

PageRank: 0/10