ISDN

ISDN (Integrated Services Digital Network) is a technology for digital transmission mainly over telephone copper line, via digital or analogue terminals. ISDN supports applications through switched and non-switched connections.

There are two kinds of access to ISDN:

• Basic Rate Interface (BRI), which consists of two 'B channels', each with bandwidth of 64 kbit/s, and one 'D channel' with a bandwidth of 16 kbit/s. Together these three channels can be designated as 2B+D.
• Primary Rate Interface (PRI) - in Europe, this contains 30 B channels and a D channel.

Much of the early work on ISDN standardization was done in ETSI committees whose work has now finished. Evolution and continued maintenance of the ISDN standards is being performed by current ETSI technical committees.

The multi-part ETSI Guide EG 201 730 provides guidelines on the publication of interface specifications that access public networks (including ISDN), in accordance with article 4.2 of the European R&TTE Directive (1999/5/EC).

Current work

Current work addresses the need to integrate networks such as the existing ISDN into the planned converged fixed/mobile network of the NGN (Next Generation Network). Recent publications concerning ISDN include:

• ETSI Standard ES 283 002 'PSTN/ISDN Emulation Subsystem (PES); NGN Release 1 H.248 Profile for controlling Access and Residential Gateways'
• ETSI Standard ES 202 314 (multi-part) 'Fixed network Multimedia Messaging Service (F-MMS)'.

ETSI has developed standards for the splitters (filters) required to separate the voice part and the data part of xDSL lines. The multi-part ETSI Technical Specification TS 101 952 includes the requirements for splitters attached to ISDN networks.

The following is a list of recently published and frequently downloaded standards. Please use the ETSI Work Programme to find further related standards.