Abstract: According to this invention, a field of useful data is split into a number of basic entities, called "data groups". Each data group is, in turn, split into smaller basic entities or "data blocks". Each resulting data block is inserted in a data packet to be transmitted through a teletext or videotext network. Therefore, an input coupler has two functional parts: a data group generator and a data packet generator.

Abstract: A one-way teletext data transmission system is an improvement over a known eletext system sold under the trademark "ANTIOPE" which transmits data having error correction and ciphering. The length of the transmitted data pack is always the maximum pack length and the value of the format byte is nil. A wire is connected from every channel to its individually associated coupler. That wire may be at either of the binary levels "1" or "0". The coupler comprises a first switch for switching between a counter and a memory. The memory stores a format byte, the value of which is nil. A second switch connects the memory to a data memory when any data packet transmission occurs, if the wire is at a predetermined binary level "1". The reception equipment is similar.