Telegraph and mobile services operations and quality of service : recommendations F.1 - F.140 / International Telecommunication Union
Telematic, data transmission and teleconference services operations and quality of service : recommendations F.160 - F.353, F.600, F.601, F.710 - F.730 / International Telecommunication Union
General characteristics of international telephone connections and circuits : recommendations G.100 - G.181 / International Telecommunication Union
International analogue carrier systems : recommendations G.211 - G.544 / International Telecommunication Union