Maxim Integrated Teridian V.22 bis Linux Softmodem for 73M1822/73M1922 MicroDAA - Manual (Page 49)

UG_1x22_043 V.22 bis Linux Softmodem for 73M1x22 MicroDAA User Guide
Rev. 1.5 49
 Bit 4 0
Select 1800 Hz guard tone to be generated during answer mode
handshake
1
Select 550 Hz guard tone to be generated during answer mode
handshake
 Bit 5 0 Disables guard tone generation
1 Enables guard tone generation
 Bit 6 0 Disable V.23 turnaround
1 Enable V.23 turnaround
 Bit 7 0 Tx 1200 bps (Bell 202 and V.23 slave mode)
1 Rx 1200 bps (Bell 202 and V.23 master mode)
S27 Call Progress Transmit Register
 0 See following.
 Bit 0 0 Send “0FFh” characters in pseudo sync (Y4)
1 Do not send “0FFh” characters in pseudo sync (Y4)

Bit 1 0 Do not transmit 1100Hz
1 Transmit 1100Hz

Bit 2 0 Do not transmit 1300Hz
1 Transmit 1300Hz
 Bit 3 0 Do not transmit 2100Hz
1 Transmit 2100Hz
 Bit 4 0 Do not transmit 2225Hz
1 Transmit 2225Hz
Bit 5 Disconnect bit
 Bit 6 0 CCITT V22bis, V22, V21, V23 (B0 command)
1 Bell 103, Bell 202, Bell 212A (B1 command)
 Bit 7 0 Protocol selection not done
1 Protocol selection done
Order of precedence is as follows from highest to lowest: Bit 1, Bit 2, Bit3, Bit 4