Conformance testing procedures for the teletex recommendations : recommendations T.64 / International Telecommunication Union
Terminal equipment and protocols for telematic services : recommendations T.65 - T.101, T.150 - 390 / International Telecommunication Union
Terminal equipment and protocols for telematic services : recommendations T.431 - T.564 / International Telecommunication Union
Data communication over the telephone network : series V recommendations / International Telecommunication Union