3Com 56K Command Reference Manual page 208

12 G
LOSSARY
V.17
V.21-Fax
V.21-Modem
V.22
V.22 bis
V.23
V.25
V.25 bis
V.27ter
V.29
V.32
V.32 bis
An ITU-T standard for facsimile operations that specifies modulation at
14.4 Kbps, with fallback to 12 Kbps.
An ITU-T standard for facsimile operations at 300 bps. 3Com or
compatible fax devices then transmit or receive at higher speeds.
An ITU-T standard for modem communications at 300 bps. Modems
made in the U.S. or Canada follow the Bell 103 standard. However, the
modem can be set to answer V.21 calls from overseas.
A ITU-T standard for modem communications at 1200 bps, compatible
with the Bell 212A standard observed in the U.S. and Canada.
An 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.
An ITU-T standard for modem communications at 1200 bps with a 75
bps back channel. Used in the U.K.
An ITU-T standard for modem communications. Among other things,
V.25 specifies an answer tone different from the Bell answer tone. All
3Com modems can be set with the B0 command so that they use the
V.25 2100 Hz tone when answering overseas calls. (Not applicable to
the Business Modem.)
An ITU-T standard for synchronous communications between the
mainframe or host and the modem using the HDLC or
character-oriented protocol. Modulation depends on the serial port rate
and setting of the transmitting clock source, &X. (Not applicable to the
Business Modem.)
An ITU-T standard for facsimile operations that specifies modulation at
4800 bps, with fallback to 2400 bps.
An ITU-T standard for facsimile operations that specifies modulation at
9600 bps, with fallback to 7200 bps.
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,
and fall forward again to 9600 bps when line quality improves.
An ITU-T standard that extends the V.32 connection range: 4800, 7200,
9600, 12K and 14.4 Kbps. V.32 bis modems fall back to the next lower