AT Command Set and S-Registers
4-14
Issue 2 May 1995
Table 4-1. AT Command Reference (13 of 18)
AT
Command Description
&P
n
DIAL PULSE RATIO
This command determines the make/break
(off-hook/on-hook) ratio during pulse dialing.
&P0
Make = 39%, Break = 61%
(for use in the United States).
&P1
Make = 33%, Break = 67%
(not recommended for use in the United States).
&Q
This command is the same as the &M command.
&S
n
DSR CONTROL
This command controls the DSR (Data Set Ready) signal
output from the modem. DSR indicates when the modem is
connected to a communications line and is ready.
&S0
DSR circuit is always on.
&S1
DSR circuit is on during handshaking, off in test or
idle modes. DSR remains on until the call is
disconnected. This mode is sometimes referred to as
Standard RS-232 operation.
&T
n
TESTS
The &T command allows you to perform diagnostic tests on
your modem.
A test started by commands &T1–&T8 will run until the &T0
command is entered, or until the timer set by S-Register S18
expires. See page 4-22 for more information on S18.
While a test is running, the modem is in Data mode.
Therefore, you must type the escape sequence (+++) to
enter online Command mode. From online Command mode,
enter &T0 to stop the test or ATO to return to Data mode
and continue the test.
&T0
Stops any test in progress.
&T1
Local Analog Loopback test. This test verifies the
modem’s internal operation, as well as the
connection between the modem and the computer.
The modem must be idle (not connected).
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