For Windows 7 Professional
1) Verify and take note of the Physical or Host COM port number (e.g. COM2). If external modem is installed on host, it must be disabled in Device Manager.
2) Configure Windows XP Mode to link Virtual COM Port with physical host COM port.
Tick “Wait for modem command to open port.”
3) Now boot Windows XP Mode
4) Go to Start > Control Panel > Phones and Modems Options.
5) Now install your modem as usual.