Embedded Modem Developer's Guide

Chapter 5 – AT Commands, S-Registers, and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI Developer’s Guide 39
Command: &R RTS/CTS Option
Description: This selects how the modem controls CTS. CTS operation is modified if
hardware flow control is selected (see &K command). The parameter
value, if valid, is written to S21 bit 2.
Default: None
Defined Values: &R0 In sync mode, CTS tracks the state of RTS; the RTS-to-CTS delay is
defined by S26. In async mode, CTS is normally ON and will turn
OFF only if required by flow control.
&R1 In sync mode, CTS is always ON (RTS transitions are ignored).
Tracks the state of RTS; In async mode, CTS is normally ON and will
turn OFF only if required by flow control.
Result Codes: OK
Otherwise ERROR
Command: &S DSR Override
Description: Selects how the modem will control DSR. The parameter value, if valid, is
written to S21 bit 6.
Default: 0
Defined Values: &S0 DSR will remain ON at all times.
&S1 DSR will become active after answer tone has been detected and
inactive after the carrier has been lost.
Result Codes: OK
Otherwise ERROR
Command: +IPR Fixed DTE Rate
Description: This numeric extended-format parameter specifies the data rate at which
the modem will accept commands during online operation. It may be used
to select operation at rates at which the modem is not capable of
automatically detecting the data rate being used by the DTE. Specifying a
value of 0 disables the function and allows operation only at rates
automatically detectable by the modem. The specified rate takes effect
following the issuance of any result code(s) associated with the current
command line.
The <rate> specified does not apply in Online Data State if Normal Mode
(Direct Mode) of operation is selected.
Default: None
Defined Values: <rate> Specifies the DTE-modem interface operation rate in bits/s.
The available rates are 0, 300, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 115200, or 230400.
If unspecified or set to 0, automatic detection is selected and the character
format is also forced to autodetect, +ICF=0.
If the rate specified is not supported by the modem, an ERROR result code
will be returned.
Report Commands: +IPR? Reports current rates
+IPR=? Reports current range Example: +IPR:
(0,300,1200,2400,4800,9600,19200,38400,57600,115200, 230400)