Abstract: Apparatus and a method for automatically configuring communication port assignments in dockable portable computer systems wherein a portable computer unit is operable both on a stand-alone basis and attached (docked) to a generally stationary expansion (docking) unit providing extended connectivity and power sourcing facilities. The portable computer unit may contain integral connectors (RS232, telephone jacks, parallel port connectors, etc.) and internal circuit devices operating through the connectors (modems, circuits supporting RS232 signalling, etc.). The docking unit may also have such connectors and associated circuits. The computer user may assign internal logical communication paths com x (x=1, 2, . . . ) to these connectors and their associated circuits. When the portable unit is in a docked mode, care must be taken that duplicate paths are not concurrently active in the portable and docking units leading to potentially conflicting signal processes in the units.