User guide

4 AT Commands, S-Registers, and Result Codes

S18 seconds 0–255 0 Sets the number of seconds that the modem

conducts an &T test before it returns to the

command mode. If the value is zero, the test

must be terminated from command mode

by issuing an &T0 or H command. When

S18 is non-zero, the modem returns the OK

message upon test termination.

S19 decimal 0–255 0 Auto Sync Bit Mapped Options: Defines the

options for Auto Sync operation (see the

&Q4 command). S19 must be set to the

desired value before &Q4 is issued.

0 Reserved

1 SBC/HDLC format select

0 =BSC selected (Default)

1 =HDLC selected

2 Address detection enable/disable

0 =Disable (Default)

1 =Enabled

3 NRZI/NZI

0 =ZRZI (Default)

1 =NZI

4 Idle indicator select

0 =Mark idle (Default)

1 =Flag or sync idle

5–7 Reserved

S20 decimal 0–255 0 Auto Sync HDLC Address or BSC Sync

Character: Defines the HDLC a address (S19

bit 1 = 1) or DSC Sync Character (S19 bit 1 =

0) for Auto Sync operation (see &Q4

command). S20 must be set to the desried

value before &Q4 is issued.

S25 hundreths 0–255 5 Sets the length of time that the modem

of a second ignores DTR while taking the action specified

(async) by &D.

S29 10 ms 0–255 70 Sets the length of time that the modem goes

on-hook when it encounters a flash dial

modifier (!) in the dial string.

S30 10 ms 0–255 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. Applies to asynchronous opera-

tion only.

S32 decimal 0–255 17 Sets the ASCII code for the XON character.

S33 decimal 0–255 19 Sets the ASCII code for the XOFF character.