31
V.17 Fax
A ITU-T standard for making facsimile connections at 14.400 bps, 12.000 bps, 9.600 bps, 7.200 bps.
V.21
A ITU-T standard for modems operating in asynchronous mode at speeds up to 300 bps, full-duplex, on public
switched telephone networks.
V.22
A ITU-T standard for modem communications at 1200 bps, compatible with the Bell 212A standard observed in the
U.S. and Canada.
V.22 bis
A ITU-T standard for modem communications at 2400 bps. The standard includes an automatic link negotiation
fallback to 1200 bps and compatibility with Bell 212A/V.22 modems.
V.27
A ITU-T standard for facsimile operations that specifies modulation at 4800 bps, with fallback to 2400 bps.
V.29
A ITU-T standard for facsimile operations that specifies modulation at 9600 bps, with fallback to 7200 bps.
V.32
A ITU-T standard for modem communications at 9600 bps and 4800 bps. V.32 modems fall back to 4800 bps
when line quality is impaired.
V.32 bis
A ITU-T standard that extends the V.32 connection range: 4800, 7200, 9600, 12,000, and 14,400 bps. V.32 bis
modems fall back to the next lower speed when line quality is impaired, fall back further as necessary, and also fall
forward (switch back up) when line conditions improve.
V.34
An ITU-T standard that currently allows data rates as high as 33,600 bps.
