scope:

The present document defines the application of CCIR Teletext System B to CCIR 625 Line 50 field Television Systems B, D, G, H, I, K and L. The System is optimized for broadcast media using cable, terrestrial and satellite transmission and the associated service and product environment. Reliable reception of data is ensured, since there is a good match between the service area defined for vision and sound reception and that provided for Teletext data broadcasting. The data is organized in a manner optimum for broadcast media by using the rigid timing framework of the television signal. When multiplexed with a video waveform, this permits a fixed relationship to be provided between the data bytes on a television signal data line and locations in the decoder memory. Using this relationship, error identification and correction are available, matched to the statistical occurrence of bit errors. Critical control data and addressing information are protected by Hamming coding. Basic data is protected by using parity checks.