Maxim Integrated Teridian V.22 bis Linux Softmodem for 73M1822/73M1922 MicroDAA - Manual (Page 12)

V.22 bis Linux Softmodem for 73M1x22 MicroDAA User Guide UG_1x22_043
12 Rev. 1.5
The following shows the actions of
DCD and DSR as viewed at the RS232 connector (inverted from pins)
during the connection process under different conditions.
1) Mode V22bis, Protocol enabled (through S25), Extended result codes.
V22bis
connection
Carrier...
result
V42
detection
Prot./connect..
result
Data
mode
DCD
DSR
2) Mode V22bis, Protocol enabled (through S25), Normal result codes.
V22bis
connection
V42
detection
connect.. result
Data
mode
DCD
DSR
3) Mode V22bis, Protocol enabled (through S25), No result codes.
V22bis
connection
V42
detection
Data
mode
DCD
DSR
4) Mode V22bis, No Protocol, Extended result codes.
V22bis
connection
Carrier...
result
Prot./connect..
result
Data
mode
DCD
DSR
5) Mode V22bis, No Protocol, No result codes.
V22bis
connection
Data
mode
DCD
DSR
O On-Line
 O0
If you have returned to Command state from Data state without breaking a
connection, the O0 command will return you on-line (Data state)
O[1-7] Retrain
O1
Similar to O0, but also causes the modem to initiate an equalizer retrain
sequence
O2 Enables the modem to respond to a remote request for retrain
O3 Disables the modem to respond to a remote request for retrain
O4 Enables speed negotiation
O5 Disables speed negotiation