By Michel Dufresne, Videotron Communications Ltee
The VIDACOM system developed by Videotron Communications Ltee has been introduced in early 1983 as a field trial in selected areas of the Videotron cable network in Montreal. This system presently supports 375,000 subscribers. This paper summarizes the major objectives of this field trial as derived from the test plan. Three major aspects are the subject of particular attention in the context of the field trial: Technology, services and network architecture.
Firstly, the field trial includes a large scale verification of the technology used in the VIDACOM system, although all new technologies were already tested through laboratory prototypes. The system is based on OSI packet data transmission at high speed of 4MB/sec. within a frequency bandwith of 6MHz (equivalent to a TV channel). The system achieves high quality transmission with 10-8 bit error rate or better. The protocol used permits both selective and interactive services.
Secondly, the field trial is used to collect precious actual information about the subscriber's behaviour with respect to new services; (text, video games, home computer, pay TV, addressability, captioning, hybrid video/data).
Thirdly, the field trial is the first "test bed" for the network architecture, based on the "open system" concept whereby the external world of information and service providers and user's peripherals equipment can be connected to the VIDACOM system using standard telecommunications protocols.