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SERIES II INTELLIGENT DATA/FAX MODEMS
2.4 Operating Your Series II Modem
You control your Series II Modem by issuing AT commands, setting
S-Registers, and setting DIP-Switches. You can easily change the settings
of your DIP-Switches, as they are located on the right side of your
Modem’s chassis. Right now your Modem is set up for the most typical
user application, that is, as a traditional modem set to make a dial-up
call to a remote installation where the call is answered automatically;
therefore, you shouldn’t need to change the DIP-Switches. (If however,
you know that your application does not follow this profile, please refer
to Chapter 9 of this manual for full details on DIP-Switch settings.)
While you may operate your Series II Modem manually, it is more
likely that you will use your data communications software to either:
• enter “terminal” mode, where you can “speak most directly” to
the modem by issuing AT commands, or to
• launch a datacomm session through a set of modem configurations
which you select and then associate with a target telephone
number. Once you have created, saved, and named this set of
information according to your connection needs and your
datacomm software’s conventions, the software then simplifies
your dialing because you needn’t re-configure your modem, nor
run the risk of mistakenly keying-in incorrect information.
Either way, you need to understand that an AT command is the method
by which your modem is controlled, and must therefore prefix nearly all
commands. AT stands for attention, and alerts the modem that a com-
mand follows. You may enter these commands with either upper- or
lowercase characters. Entering AT automatically sets the modem’s serial
baud rate to match your computer’s and also sets the modem’s parity. It
also clears the modem’s command buffer.
Once you’re in terminal mode, enter AT followed by <CR> to check
whether your modem is operational. If everything’s fine, your modem
will respond OK. (If your Modem is a 336+ [MD1640A] model, refer to
Chapter 4 for additional details on Dialing, Automatic Answering, Dial
Back-Up and Automatic Leased Line Restoral.)