Select the device line you wish to configure from the drop down list and press "Configure Line" to change each line settings.
There are 2 configurations available for modems depending on whether it operates as a speakerphone or not.
When the modem is not a speakerphone, its sound streams are emulated directly from the device hardware so the button "Select Sound" is disabled.
If the modem operates as a speakerphone, you also need to configure the sound card. In this case the "Select Sound" button is available.
Hang up detect delay is the amount of time it takes from when the caller disconnects the call and the modem detects it. This removes silence from the end of voice mail messages.
Further information regarding Location, Line, and Phone selection can be found from your windows help files as well as the control panel\Phone and Modem icon.