Also known as: CCITT, International Telegraph and Telephone Consultative Committee
CCITT (the International Telegraph and Telephone Consultative Committee, French Comité Consultatif International Téléphonique et Télégraphique) was the ITU body renamed ITU-T in 1993. Its names still label standards behind RTTY, telephone modems, and speech codecs.1
Overview
The CCITT was, for most of the 20th century, the standards arm of the ITU responsible for telegraphy and telephony. Meeting in study groups and plenary assemblies, it produced the “Recommendations” that made national telephone and telegraph networks interconnect across borders. In the 1992–1993 ITU reorganisation the CCITT was renamed the ITU Telecommunication Standardization Sector (ITU-T), which carries on the same work and the same Recommendation numbering; its sister sector, ITU-R, handles radiocommunication. Because the renaming preserved the numbering, a great many standards are still known and cited by their original CCITT names.
Several of those touch signals an SDR user meets. The CCITT No. 2 telegraph alphabet — also called ITA2 or Baudot — is the 5-bit character code that underlies RTTY (radioteletype), still heard on the HF bands. The V-series Recommendations defined the telephone-line modem standards (V.21, V.22, V.32, V.34, and beyond) whose modulation and handshaking ideas echo through modern data modes. And the G-series defined the digital speech codecs of the telephone network, most famously G.711 pulse-code modulation and its relatives, which set the template for how voice is digitised. Presenting CCITT as the historical predecessor of ITU-T is the accurate framing: the organisation did not disappear so much as change its name and keep publishing.
Relevance to SDR
CCITT-lineage standards describe the letters and tones of some of the oldest decodable digital signals on the air. When an SDR user copies RTTY, the decoder is mapping mark/space tones back into ITA2 characters exactly as the CCITT No. 2 alphabet defines them. Older HF and phone-patch data modes trace their modulation lineage to the V-series, and the G-series codecs describe how sampled voice is represented in countless digital systems. Knowing that these carry CCITT names — now formally ITU-T — helps a listener follow documentation that predates the 1993 rename.
These legacy modes sit outside GopherTrunk’s land-mobile trunking focus, so GopherTrunk does not itself decode RTTY or telephone modems; dedicated tools handle those. The reference stands as context for the wider RF landscape an SDR user explores, and it resolves the common confusion between the historical CCITT name and today’s ITU-T.