Black Box MD1641A, MD1640A manual Operating Your Series II Modem

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.)

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