SMPTE RP 220-2004

This practice defines a standard manner for the delivery of SMPTE DDE content for both transport A (broadcast of triggers and pulling of data by the return channel) and transport B (broadcast of triggers and data) for the 625-line television system. Both transport types are based on carriage of IP multicast packets in VBI lines of a PAL/SECAM system by means of teletext packets with address 30 or 31.