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All necessary components are installed with PVI Setup.
As with serial communication (RS232/RS422), modem communication is also a point-to-point connection.
•Transparency: Standard Windows functions are used to access the modem. In other words, all modems that can be installed in Windows can be used. The user just needs to install the modem and doesn't need to know anything else about modem technology (AT commands, etc.).
•Automatic connection establishment: An active, created connection (see below) is constantly monitored. If the connection is lost (e.g. telephone line interrupted, modem disconnected or turned off), it tries to re-establish the connection in periodic intervals. The number of attempts as well as the intervals between attempts can be configured.
•Active connection: Windows establishes a dial-up connection with a specified telephone number and transfers the protocol determined by the PVI line over this connection.
•Passive connection: Windows waits for an incoming call, answers automatically, and makes the connection. In this operating mode it is possible, for example, that a PLC initializes the connection to a Windows computer itself.
The PVI modem requires Microsoft TAPI version 2.0. This version is already installed in Windows NT 4.0. When using Windows 95, it is necessary to replace the standard TAPI Version 1.4 with a newer version. The current version from Microsoft (www.microsoft.com) is version 2.1 To install TAPI Version 2.1 in Windows 95, start the "tapi2195.exe" program in the "Pvi\SysSetup\Modem" directory. This file is installed with the PVI Setup option "Modem System Components".
A modem is installed in the Windows Control Panel under Modems. A new modem can be added in the dialog box and its settings can be edited ("Properties"). The modem name shown in this dialog box corresponds to the modem name which needs to be specified as a PVI device parameter (/MO).
Dialing details are set in "Control Panel – Modems" (current location, calling card, etc).