AT Command Set and S-Registers
4-22
Issue 2 May 1995
Table 4-2. S-Register Reference (3 of 5)
S-Register
Description
S11=
n
DTMF TONE TIMER
This S-Register controls the length of the DTMF (touch tone)
on time. This register is not used for pulse dialing.
n = 50–255 milliseconds.
Factory setting is 95ms.
If you enter a value less than 50, then 50 ms is used. If you
enter a value higher than 255, then 255 ms is used.
NOTE: If Automatic Cellular Setup is enabled (C0), the
minimum value is 120 ms.
S12=
n
ESCAPE GUARD TIME
This S-Register sets the value (in 20-millisecond
increments) for the required pause before and after the
escape sequence (+++) is issued.
n = 0–255 (20-millisecond increments).
Factory setting is 50 (1 second).
S18=
n
TEST TIMER
This S-Register sets the duration (in seconds) for modem
loopback tests issued by the &T command. After this timer
expires, the modem returns to Command mode.
Setting S18 to zero disables this timer and the loopback test
must then be stopped by issuing the escape sequence
(+++), followed by an ‘AT&T0’ or ‘ATH’ command.
See page 4-14 for more information on the &T command.
n = 0–255 (seconds).
A value of 0 disables the timer.
Factory setting is 0 seconds (timer disabled).
S25=
n
DTR DETECTION
This S-Register sets the length of time that the modem
ignores DTR before hanging up.
The S-Register sets the length of time the modem waits
before responding when the DTR signal is no longer
detected.
n = 0–255 (1/100 seconds).
A value of 0 disables the delay (the modem responds
immediately). A value of 255 creates an infinite delay (the
modem ignores the change in the DTR signal).
Factory setting is 0 (timer disabled).
