G
LOSSARY
86
V.27
An
ITU-T
standard for
facsimile
operations
that specifies modulation at 4800 bps, with
fallback to 2400 bps.
V.29
An
ITU-T
standard for
facsimile
operations
that specifies modulation at 9600 bps, with
fallback to 7200 bps.
V.32
An
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
An
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 (see
online fall back/fall
forward
).
V.34
An
ITU-T
standard that currently allows data
rates as high as 33,600 bps.
V.42
An
ITU-T
standard for modem
communications that defines a two-stage
process of detection and negotiation for
LAPM
error control
.
