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Modem Control/Dial-up Connections
3.1 Modem Control and RS232C Interface
Please make sure for the command and dial-up mode that DIP switches 1 and 2 are both OFF
(see "DIP Switches" on page 12).
Interfacing with the controller (computer or PLC) often referred to as DTE (Data Terminal
Equipment) is done through a serial asynchronous RS232C interface. The adjustment of the
interface parameters, such as baud rate and number of data bits and number of control bits, is
carried out automatically by the modem (in command mode). As soon as the character
sequence "AT" or "at" is entered into the modem, the settings are recognized automatically.
If no characters are sent (as is the case with the PLC's tool port), the port's baud
rate cannot be recognized. Therefore, set a fixed baud rate using the AT*W=...
command (see "Command Tables" on page 68).
The control of the modem follows the AT-Hayes command set. The commands are transmitted
from the controller to the modem in the form of ASCII data. These commands can be sent from
a control program or can be entered manually via a terminal program.
Basic configurations, so-called profiles, are stored in the modem, making instant use without
any configuration possible (see "User Profiles and Factory Settings" on page 37).
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FP Modem-EU Technical Manual
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