from
The Free On-line Dictionary of Computing (8 July 2008)
V.24
<standard> The {ITU-T} {standard} defining interchange
circuits between {DTE} and {DCE}. V.24 is the {ITU-T}
equivalent of {EIA} standard {EIA-232C}, though V.24 only
specifies the meaning of the signals, not the connector or the
voltages used.
V.24 recommends 12 {modem} {carrier} frequencies that will not
interfere with {Dual Tone Multi-Frequency} or other telephone
control tones. These are:
GROUP A = 920 Hz, 1000 Hz, 1080 Hz, 1160 Hz
GROUP B = 1320 Hz, 1400 Hz, 1480 Hz, 1560 Hz
Group C = 1720 Hz, 1800 Hz, 1880 Hz, 1960 Hz
(2004-08-02)