Analogue

Overview

The terrestrial data broadcast service uses transmission capacity (three VBI line pairs on Channel 3 and three on Channel 4) within the UK Channel 3 and 4 transmitter network which is operated for DBI by Arqiva Ltd. This network provides 99.4% coverage of the United Kingdom including the Channel Islands, Shetland Islands, all islands off the west coast of Scotland and Northern Ireland. The service is provided on a 24 hour per day basis throughout the year.

DBI's broadcast system conforms with the World Standard Teletext & Data Broadcasting System specification - published by the European Telecommunications Standards Institute (ETSI). Both Packet 31 (Section 21) and Conditional Access - Page Format (Section 20) schemes are supported.

The DBI Data Centre in Egham acts as the gateway into this network. It is to the Data Centre that the clients deliver the data for broadcast usually either by leased line or by modems on the PSTN (Public Switched Telephone Network). The data is then distributed to all the transmitter sites within the Channel 4 national digital video distribution network which is operated by BT.

Resilience of the network is extremely important. To that end, all equipment is duplicated, all digital circuits are diversely routed and two video chains drive each transmitter. Uninterruptible Power Supplies (UPS) provide standby power to all the equipment sites except for the transmitters which take two different feeds from the National Grid.

Automatic monitoring and direct alarming to pagers is provided by the network ensuring a fast response and a very high degree of system availability. Engineering support is provided on a continuous 24 hour basis by the provision of paging and voicebank facilities outside the operational hours of the Help Desk, which provides a single point of contact for fault reports and decoder enabling/disabling functions between the hours of 9:00 am and 5:00 pm Monday to Friday.

If you need any further information or have any queries please do not hesitate to contact us.