Transmission using 6-bit Transcode had higher throughput than transmission using 8-bit EBCDIC or ASCII, provided that the data to be transmitted used a limited set of 48 characters.
The IBM 2780 data transmission terminal was announced with Transcode support in 1967.
Its successor, the IBM 3780 data communication terminal, announced in 1972, dropped Transcode support and added a "space compression" option.
It relates to IBM's punched card code but, like EBCDIC, it is not BCD.
Its 64 values consist of the 26 uppercase letters, 10 numbers, 11 symbols, space, and 16 control characters.