A computerized telephony call center for serving a customer base has a central switch connected to a plurality of telephones at operator workstations and adapted to route calls to individual ones of the telephones, and also connected to a public switched telephone network, and a first processor connected to the central switch by a high-speed data link and to the telephone network by a digital network connection. The first processor is adapted to monitor transactional activity of the central switch, to process the activity information according to selected routines in the processor, and to communicate processed information to a second processor over the digital network connection. The digital network connection may be a TCPP connection. In a preferred embodiment the first processor is connected by a local area network (LAN) to network interfaces including a video display unit (VDU) and input apparatus proximate individual ones of the plurality of telephones connected to the central switch. In some embodiments the LAN is also connected to a data server running an instance of a database. In other embodiments the call center, and other similar call centers are all part of a call routing system wherein calls are routed from Service Control Points to call centers over telephone lines, and data is routed to the call centers over a separate digital network connection between processors coupled to the Service Control Points and to the call center central switches. In various embodiments aspects of the invention apply to Internet protocol network telephony (IPNT) calls as well as to conventional telephony calls.