AT Commands and S-Registers
4-273821-A2-GB20-40 January 1999
Initialization Strings
An initialization string contains several AT commands
that are entered at once to program the modem for a
specific application.
The following initialization strings identify essential
AT commands that directly impact modem operation for a
particular application. If you need to modify these strings
for your application, make sure additional commands are
inserted somewhere in the middle of the initialization
string. Whenever an &L command is used, it must appear
at the end of an initialization string.
V.25bis Applications
For V.25bis HDLC (High-level Data Link Control)
dial-line operation, create an initialization string with the
following commands. Note that the character format can
be 8 data bits, no parity, and 1 stop bit; 7 data bits, odd
parity, and 1 stop bit; or 7 data bits, even parity, and
1 stop bit:
TYPE: AT&F &D1 &S1 &M234 &W
PRESS: Enter
For V.25bis bisync operation, create an initialization
string with the following commands. Note that the
character format must be 7 data bits, odd parity, and
1 stop bit:
TYPE: AT&F &D1 &S1 &M233 &W
PRESS: Enter
Synchronous Leased-Line Applications
For synchronous leased-line operation, create the
following initialization string with the following
commands:
TYPE: AT&F &D1 &S1 S44=n S45=n S82=n
&M1 &W &Ln &W
Where: n is the value for the AT command. Refer
to either Table 4-1 or Table 4-2 to
determine the best possible values for
these commands.
PRESS: Enter
AT&T Exclusive Dialing
for DATAKIT Applications
For AT&T exclusive dialing for DATAKIT
applications, create an initialization string with the
following commands:
TYPE: AT&F &C5 &D1 &S3 &R0 \D3 \Q1 \G1
S85=1 &M235 &W
PRESS: Enter
