Modem User Manual

Chapter 1 – AT Commands, S-Registers and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5634SMIxx Reference Guide (S000263C) 13
Command: &Ln Leased Line Operation
Values: n = 0, 1, or 2
Defaults: 0
Description: &L0 The modem is set for standard dial-up operation.
&L1 The modem is set for leased line operation in originate mode.
&L2 The modem is set for leased line operation in answer mode.
Note: For &L1 and &L2, there is a 30-second window between power up and the
starting of the leased line handshake. During this time, you can turn off the
command, if desired.
Command: &Pn Pulse Dial Make-to-Break Ratio Selection
Values: n = 0, 1, or 2
Default: 0
Description: &P0 60/40 make-to-break ratio
&P1 67/33 make-to-break ratio
&P2 20 pulses per second
Note: The &P2 command is available only if the country code is set to Japan.
Command: &Qn Asynchronous Communications Mode
Values: n = 0, 5, 6, 8, or 9
Default: 5
Description: &Q0 Asynchronous with data buffering. Same as \N0.
&Q5 Error control with data buffering. Same as \N3.
&Q6 Asynchronous with data buffering. Same as \N0.
&Q8 MNP error control mode. If MNP error control is not established, the modem
falls back according to the setting in S36.
&Q9 V.42 or MNP error control mode. If neither error control is established, the
modem falls back according to the setting in S36.
Command: &Sn Data Set Ready (DSR) Control
Values: n = 0 or 1
Default: 0
Description: &S0 DSR is always ON.
&S1 DSR goes ON only during a connection.
Command: &Tn Loopback Test (V.54 Test) Commands Values: n = 0, 1, 3, 6
Default: None
Description: The modem can perform selected test and diagnostic functions. A test can be run
only when the modem is operating in non-error-correction mode (normal or direct
mode). For tests 3 and 6, a connection between the two modems must be
established. To terminate a test in progress, the escape sequence (+++AT) must
be entered.
&T0 Stops any test in progress.
&T1 Starts a local analog loopback, V.54 Loop 3, test. If a connection exists when
this command is issued, the modem hangs up. When the test starts, a
CONNECT message is displayed.
&T3 Starts local digital loopback, V.54 Loop 2, test. If no connection exists,
ERROR is returned.
&T6 Initiates a remote digital loopback, V.54 Loop 2, test without self-test. If no
connection exists, ERROR is returned.