This first step of the ISDN configuration wizard provides you with
various options:
Detect an internal card: The selection of this icon will
bring up a list of the ISDN cards detected on your machine. If you
have an internal card, try this option first. Otherwise you will
either need to:
Select an internal card: A list of supported ISDN cards will
be shown if the previous step has failed.
Configure an external modem: Select this icon if you have an
external modem, not an internal ISDN card.