2003 January

January 2003

The TEL: URI points to a phone number. It does not try to explain HOW to reach this end point, just focuses on the end point. The SIP URI is protocol dependent, whereas in the TEL: URI the user may choose protocol or method to place the call.

This document defines the URI scheme \”tel\”. The \”tel\” URI describes resources identified by telephone numbers. A telephone number is \”a string of decimal digits that uniquely indicates the public network termination point. The number contains the information necessary to route the call to this termination point.\” The \”tel\” URI telephone number is not restricted in the type of termination point it refers to. The termination point can be in the public telephone network, a private circuit-switched network or the Internet. The termination point can be a mobile terminal or a landline circuit. The terminal addressed can support voice, data or fax. The URI can refer to originators or targets of a telephone call.


Merging cellular, WLAN and SIP is a marvellous idea. This is the start of the next generation telecom network:

\”Motorola Inc. (NYSE: MOT), Avaya Inc. (NYSE: AV), and Proxim Corporation (NASD: PROX) today announced they will collaborate on the creation and deployment of converged cellular, Wireless Local Area Networking (WLAN), and Internet Protocol (IP) Telephony solutions that will deliver new levels of communications mobility and network connectivity. These solutions will be enabled by an array of new products including a Wi-Fi/cellular dual-system phone from Motorola, Session Initiation Protocol (SIP)-enabled IP Telephony software from Avaya, and voice enabled WLAN infrastructure from Proxim.

When we\’re migrating telephony to IP networks, we have to understand the requirements put on all kinds of telephony to handle emergency situations. IETF have published an Draft that discusses these requirements. From the abstract:

Effective telecommunications capabilities can be imperative to facilitate immediate recovery operations for serious disaster events, such as, hurricanes, floods, earthquakes, and terrorist attacks. Disasters can happen any time, any place, unexpectedly. Quick response for recovery operations requires immediate access to any public telecommunications capabilities at hand. These capabilities include: conventional telephone, cellular phones, and Internet access via online terminals, IP telephones, and wireless PDAs. The commercial telecommunications infrastructure is rapidly evolving to Internet-based technology. Therefore, the Internet community needs to consider how it can best support emergency management and recovery operations.