Toshiba DP120F Service Manual page 578

NOTES: 1. In the V.34 procedure, ECM is used. If the ECM transmission/reception
of user data is set to "Not performed", the V.8 procedure is not per-
formed. Therefore, the procedure does not switch to V.34, and V.17 or
the prior, is selected.
2. Also when the transmission/reception speed is set to 14.4 kbps or less,
the V.8 procedure is not performed, and V.17 or the prior, is selected.
3. To switch to the V. 8/V.34 procedure after starting V.21 procedure, see
"c-1".
4. After the V.34 procedure starts, fallback is performed in the V.34 proce-
dure. However, fallback for V.17 mode or before is not performed.
DP120F/DP125F Dialing and Communication Procedure 9-14 March 2000 © TOSHIBA TEC