Also known as e164.arpa -- after the worldwide e.164 numbering system that defines each unique phone number -- ENUM connects conventional phone numbers with Web pages, Internet fax services and other online resources. Subscribers to an ENUM service register their other contact details, then set up rules that control how and when calls to their phone are routed. For example, calls from anybody but close family could be routed straight to voicemail between 6pm and 11pm.
Because it connects to any IP service, incoming callers could also use phone numbers to access Web sites, the Skype voice over IP (VoIP) application, faxes and other applications. Phone numbers entered into a browser's address bar would resolve to the correct Web address, or could be used from mobile phones to send an e-mail without having to remember the recipient's e-mail address.
-Defining what ENUM is, is always a struggle," said Allan Horseley, previous managing director of the Australian Telecommunications Users Group and a member of the Australian Communications Authority (ACA), at the launch. It allows users -to set the ground rules for people contacting them," he continued, adding that he saw -substantial" opportunities for ENUM in the VoIP arena.
ENUM was defined several years ago and is an accepted Internet Engineering Task Force standard, but the Australian trial - driven by the ACA in response to earlier public discussions - is the first in our hemisphere and among the first in the world. The local trial will begin on June 6.
Registrar service provider AusRegistry International -- with low-level access to the Domain Name Service (DNS) services that make the World Wide Web possible -- will onsell high-level ENUM resolution services to domain name registrars including trial participant Enetica. AARNET, a network operator serving over 930,000 users at all Australian universities, is also participating to spur innovative applications based on ENUM. AusRegistry will bear the costs of the trial, and is in talks to sign on additional registrars.
Generating interest around ENUM will be difficult -- -there is a steep learning curve to understand the telephony side of things," conceded AusRegistry general manager Adrian Kinderis, -but there are huge benefits outside the commercial aspect."
Just what those benefits are, was not immediately clear, however. One potentially interested group would be commercial VoIP providers, who -- assuming ENUM is implemented as an add-on to existing numbers -- would be able to switch customers to VoIP services without forcing them to change their numbers, traditionally a major obstacle to customer adoption. Conventional carriers could also use it to carry customer calls over their own VoIP networks, which reduce carriers' own costs of providing various calls.
It's not the first time so-called "follow-me" services, which give customers a single number that can be used to contact them at anywhere and any time, have been tested in Australia. Several years ago, the introduction of the 0500 number range was expected to spur a communications revolution -- but those services died a quick and quiet death after consumers failed to bite.
Whether ENUM can succeed where 0500 failed, remains to be seen. Coonan highlighted ENUM's role in hastening convergence between traditional telecommunications and IP-based networks: -This is an important test of one possible way of building interoperability," she said.
In the first phase of the ENUM trial, participants will be given new numbers with the 059 prefix. A coming second phase will extend the service to mobile numbers, but the timeline for use of ENUM for all fixed lines is cloudy due to a complex legislative environment.
Long-term plans for ENUM will be reviewed after the year-long trial is completed. For now, the focus is on encouraging interested parties to explore potential applications. -The biggest issues we've had are from a regulatory point of view, not a technical one," said Bennett Oprysa, chief operations officer with Enetica, which will provide interested customers with development toolkits that let them experiment with ENUM.