A method and system for automatically identifying the type of communication interface used to couple a portable computer system with a second computer system, and for selecting the form of an application that is used with the type of interface. For example, a debugger application is collaboratively executed on the computer systems over the interface. When entering the debugger mode, software executed on the portable computer system identifies the type of interface by reading a resistance value of a pin. After determining the type of interface, the form of the debugger used with the interface is automatically selected. A similar process is followed for other applications that depend on the type of interface. The user does not have to manually identify the type of interface. Instead, in response to a command that is independent of the type of interface, the proper form of the application is automatically selected.