ENUM is a new registry service that combines telephone numbers and the Domain Name System to simplify the way that VoIP calls (telephone calls made over the Internet) work. It allows more VoIP calls to be connected directly over the Internet, for no charge, rather than via the traditional PSTN network.

ENUM translates a telephone number into a domain name. This allows users to continue to use the existing phone number formats they are familiar with, whilst allowing the call to be routed using DNS.  This makes ENUM a quick, stable and cheap link between telecommunications systems and the Internet.

Initial benefit of ENUM - cheaper calls between VoIP systems

The most important benefit of ENUM is that it enables a business or consumer with a VoIP system to locate other businesses or consumers with VoIP systems and call them directly across the Internet, bypassing the ordinary telephone system and thereby costing no more than the rental already being paid for the Internet connection.

Future benefits - sophisticated applications

ENUM allows you to publish much more information to be associated with your telephone numbers than just how to make a call to that number. For example you can publish your postal address details, your email details or other location information. We anticipate interesting applications that take advantage of this to start to appear and provide even greater benefit to using ENUM.