Broadcast Service Data Packet

The Broadcast Service Data Packet (BSDP) carries broadcast service data relating to the television channel. It is transmitted in packet 8/30 (packet 30 of magazine 8) and is one of two formats depending on the designation code.

The least significant bit of the designation code is used as a flag to indicate whether the teletext signal is confined to the vertical blanking interval of a video signal, or uses all available lines for a full field transmission system. The remaining bits define the format type.

In both formats the first six bytes define the initial page number of the teletext service, and the final 20 bytes carry a status message.

Format 1 packets contain a Network Identification code, the current date, time, and offset from UTC.

Format 2 packets relate to Programme Delivery Control and contain programme identification data for the automatic control of video recorders.

The BSDP was previously referred to as the Teletext Service Data Packet (TSDP).