Filter
Top Products
Chapter 5 – AT Commands, S-Registers, and Result Codes
SocketModem Global MT5634SMI Developer’s Guide 40
S-Registers
Certain modem values, or parameters, are stored in memory locations called S-registers. Use the S command to
read or to alter the contents of S-registers (see previous section).
Register Unit Range Default Description
S0 1 ring 0, 1–255 1 Sets the number of rings until the modem answers. ATS0=0 disables
auto answer completely.
S1 1 ring 0–255 0 Counts the rings that have occurred.
S2 decimal 0–127 43 (+) Sets ASCII code for the escape sequence character.
128–255 Values greater than 127 disable escape.
S3 decimal 0–127 13 (^M) Sets the ASCII code for the carriage return character.
S4 decimal 0–127 10 (^J) Sets the ASCII code for the line feed character.
S5 decimal 0–32 8 (^H) Sets the ASCII code for the backspace character.
33–127 Values greater than 32 disable backspace.
S6 seconds 2–65* 2* Sets the time the modem waits after it goes off-hook before it begins
to dial the telephone number.
S7 seconds 35-65* 50* Sets the time the modem waits for a carrier signal before aborting a
call. Also sets the wait for silence time for the @ dial modifier.
S8 seconds 0–65 2 Sets the length of a pause caused by a comma character in a dialing
command.
S9 decimal 0, 1–127 37 (%) Sets ASCII code for remote configuration escape character. S9=0
disables remote configuration.
S10 100 ms 1–254 20 Sets how long a carrier signal must be lost before the modem
disconnects.
S11 1 ms 50–150* 95* Sets spacing and duration of dialing tones.
S28 decimal 0, 1–255 1 0 disables, 1–255 enables V.34 modulation.
S30 1 minute 0, 1–255 0 Sets the length of time that the modem waits before disconnecting
when no data is sent or received. A value of zero disables the timer.
See also the \T command
S35 decimal 0–1 1 0 disables, 1 enables the V.25 calling tone, which allows remote
data/fax/voice discrimination.
S36 decimal 0–7 7 Specifies the action to take in the event of a negotiation failure when
error control is selected. (See S48.)
S37 decimal 0–19 0 Sets the maximum V.34 “upstream” speed at which the modem
attempts to connect.
0 = maximum speed
1 = reserved
2 = 1200/75 bps
3 = 300 bps
4 = reserved
5 = 1200 bps
6 = 2400 bps
7 = 4800 bps
8 = 7200 bps
9 = 9600 bps
10 = 12000 bps
11 = 14400 bps
12 = 16800 bps
13 = 19200 bps
14 = 21600 bps
15 = 24000 bps
16 = 26400 bps
17 = 28800 bps