
V.22 bis Modem with AT Commands
CMX866
©
2008 CML Microsystems Plc
18
D/866/5
S Registers
Parameters Function
Default
S11
5…255
DTMF tone duration and interdigit pause duration in units of 10ms
100ms
S12
0…255
Escape code guard time in units of 50ms
1s
S13
Reserved
S14 0…255
General
Options
$92
S15
0…255
Loopback carrier off time in units of 10ms
80ms
S16
0…255
Drop time for loopback in units of 10ms
60ms
S17
0…255
Handshake timeout (Answering) in seconds
30s
S18
0…255
Loopback timer (0= no timeout) in seconds
0s
S19
Reserved for test functions
S20
Reserved
S21
0…255
Loopback and Power states
$10
S22
0…255
Calling and response characteristics selection
$C0
S23
0…255
Guard tone selection
$00
S24
0…255
Equaliser, DCD, DTR status and modulation fallback
$A9
S25
0…255
TX Gain, TX data format
$B0
S26
0…255
RX Gain, RX data format, overspeed (2.3% default) setting
$30
S27 0…255
Communications
Protocol
$00
S28
0…255
RTSN Timeout for return to Command mode from Data mode in seconds
0s
S29
0…255
Timed Break Recall period in units of 10ms
300ms
Bn Register
Parameter Communications
Protocol
Fallback
n
(Mapped to S27 register)
0
V.22bis 2400bps QAM
V.22
1
V.22 1200bps DPSK
2
V.23 Tx 75bps, Rx 1200bps (Master)
3
V.23 Tx 1200bps, Rx 75bps (Slave)
4
Reserved
5
V.21 300bps FSK
6
Bell 212A 1200bps DPSK
7
Bell 202 Tx 150bps Rx 1200bps
8
Bell 202 Tx 1200bps Rx 150bps
9
Bell 103 300bps FSK
Xn Register
Parameter
Calling and Response Characteristics
n
(Mapped to S22 register)
0
Ignore dial tones and busy tones, return CONNECTxxxx or NO CARRIER
1
Ignore busy tone, wait for dial tone to dial. Return NO DIAL TONE or
CONNECT xxxx or NO CARRIER
2
Ignore dial tone. If busy tone detected, return BUSY. Return CONNECT xxxx
3
Return NO DIAL TONE, BUSY, CONNECT xxxx, or NO CARRIER