Architecture of an highly modular packet switching ISPBX

An integrated services private branch exchange (ISPBX) based on a packet switching subnetwork, designed to provide support for ISDN communications between local, or local and remote terminal equipment, according to I Series of CCITT Blue Book Recommendations is presented. The general system architecture and features, the main characteristics of the switching subnetwork, and the general outlines of the module´s organization are described. Also included is a brief description of the features of ISP, a protocol used for internal signaling and D-channel packet communications purposes