Most modems can be accessed using Wine, but there still is no (full) support for winmodems as they seem to be incompatible to most common modem's installations.
If you want to use COM1 with a modem connected to /dev/ttyS0, COM1 has to be set up to provide this. You also have to set up the serial port for use by the user as described above. It is a good idea to test the modem access using minicom before configuring and testing a Wine application.
Programs such as win3.1's "terminal.exe" offer a simple way to set up and test your modem under Wine.
If windows finds your modem on Com2 and your Linux port is ttyS1 then, to set up the modem in wine.conf change to:
$ wine -desktop 1080x900 terminal
You may get a windows error message which says that the Com port you are trying to use was "unavailable or in use by another program." This can be fixed by changing the permissions on /dev/ttyS1 but best practice is to add the user to the group to which the port belongs.
With terminal running clicking on "Settings|Phone number" brings up a child window with a place to enter the phone number. Enter the number, close, then "Phone|Dial" and the program will dial the number you entered. If all goes well, your modem is now working under Wine. Terminal will now display an edit window showing the progress of your connection and you can login to the remote site.