Abstract: The adjunct call processing arrangement of our invention eliminates the separation between hard-wired telephone switching system computer facilities and customer owned switchably connectable computer facilities. A general purpose communication interface is provided which connects the customer provided computer facilities to both the switching network and the hard-wired system processor of the telephone switching system via the standard telephone switching system port circuit. This general purpose communication interface enables a customer provided computer facility to provide additional call processing capability. In particular, the attendant services call processing subroutines and the directory assistance data base and software are provided on the computer facility. The telephone switching system routes all attendant-directed calls to a telephone station set associated with the computer and transmits call related data to the computer.