G.703 is an encoding standard developed by the International Telecommunication Union (ITU) that was widely used in Europe and not used at all in North America. See full details about this standard.
What is G.703?
G.703 is an encoding standard developed by the International Telecommunication Union (ITU) for interfacing data communications equipment (DCE) with digital high-speed synchronous communication services.
G.703 is not used in North America but was widely used in Europe, and it covers specifications for digital transmission from rates of 64 Kbps to 2.048 Mbps. Private Branch Exchange (PBX) systems often use 64-Kbps leased lines utilizing the G.703 standard, as do E-carrier services such as E1 communication links.
Some U.S. vendors sell converters for connecting synchronous V.35, RS-449, or X.21 interfaces to G.703 in order to sell their switching equipment in Europe.
G.703 has been updated to include support for U.S. standard T-carrier service speeds, such as T1 transmission at 1.544 Mbps.