The following requirements have to be fulfilled, so that the modem connection can be used with a driver.
The driver has to support the connection to the PLC vie modem. Whether the driver supports a connection vie modem, can be seen in the
configuration dialog Com. If the checkbox Modem connection is available, the driver can connect to the PLC via modem.
The connection to the modem is realized via the Windows interface TAPI (Telephony Applivation Program Interface). So a TAPI modem has to be configured.
On the opposite side a modem operation also has to exist.