SUMMARY OF THE ROCKWELL "AT" COMMAND SET
To communicate using the modem, use an asynchronous communication program. The command
set for the modems is compatible with the Hayes command set.
The modem is controlled and configured by the AT (attention command). Each command consists
of the following elements (with the exception of the A/and the +++ command that will be discussed
later). A command is not entered until a carriage return <ENTER> is entered. Spaces entered are
ignored. For example, to enter the command `Answer', type ATA and <ENTER>.
Some commands do not have parameters. Any missing parameters in a command is assigned the
value zero, which may be a valid parameter for the command. The sequence followed by AT
command causes the modem to enter a command state. That is, AT without a command serves as
a wake up code and an "OK" appears on the screen. The modem queues the commands in a 40-
character command line. The command line begins with AT and can have several commands. A
separator is not required between the commands.
When a carriage return is received, the commands are performed in the order in which they are
sent to the modem. If more than 40 characters are sent to the modem, an error occurs and all
commands must be re-entered.
A common configuration for a remote modem is to answer the call and hang up on
loss of carrier. To do this the RS232 interface has to be set for the correct
configuration.
Option if the Computer uses pins 2, 3, & 7 only - Set the AT commands as follows
ATS0=1 (modem will answer on the first ring)
AT&D0 (modem will ignore DTR)
factory default is AT&D1 which allows the modem to answer only if
DTR is high.
AT&V to check the state of the "S" registers use AT&V
AT&W0 Don't forget to burn the new codes into E-PROM by AT&W0
To see your typing you made need to turn on E1 for the modem to echo back responses. Some
software doe not like it's data echoed back so don't forget to check E1/E0 if your software is acting
strange.
Note:
you may want to put the modem into a quiet mode - ATQ1 (ATQ0 is the default) modem does not send result codes -
which can confuse the computer
.
A good configuration for a dumb mode operation is
AT&F&C1&D0E0Q1S0=1&W0
AT&F&C1&D0E0Q1S0=1&W0
