ISDN: (Integrated Services Digital Network)
ISDN-based videoconferencing provides a guaranteed picture and audio quality at a known price. It is therefore mainly suited for group meetings, long-distance interviewing and similar applications where high-quality audio and reasonable-to-good quality picture is necessary.
ISDN is supported by telecoms service providers throughout the UK, Europe, North America, the Far East and Australia.
The ISDN service is designed to provide reasonably high data transmission rates for digital data and its digital telephone links can be used to support videoconferencing. Each ISDN channel provides 64 kilobits of data per second (kbps). At least two ISDN channels are used for videoconferencing (ISDN-2), hence for links in UK the cost is twice that of a voice telephone call.
ISDN videoconferencing between more than two sites will require the use of a Multipoint Control Unit (MCU). Each site calls the MCU site, and its location will determine the cost of the call. There may also be charges for the use of the MCU depending upon the service provider. The MCU normally operates with voice-activated picture switching while maintaining open audio between all the sites in the videoconference.
Internet Protocol (IP) videoconferencing
IP (Internet Protocol) videoconferencing is more widely used to communicate between individuals where the quality of the picture is not so critical. This technology is currently free to the user since it uses the Internet, but does not provide a guaranteed picture and audio quality as it is dependent on Internet traffic, which varies enormously.
At present, IP calls are not available to external clients due to the terms and conditions imposed by our network provider.