An automatic call distributor (10) with a plurality of subnetwork switches (14A, 14B) for interconnecting agent units (18A, 18B) with customer telephonic units (15) of an external telephonic network (16) and a host data base computer for storing customer information obtained from agents (18A, 18B) of all the subnetworks (11A, 11B) with an intersubnetwork transfer system for transferring customer information stored in the host data base computer and obtained from an agent (18A, 18B) of one of the networks (11A, 11B) to a display terminal (22B, 22A) of an agent (18B, 18A) of another one of the subnetworks (11B, 11A) by the method (FIG. 4) of conveying call identification information (FIG. 3) including both subnetwork switch port identification and subnetwork trunk identification to the host data base computer (12) for association with the stored customer information and to the other subnetwork (11B, 11A) during an intersubnetwork transfer.