The basic concept of switching control in CTRON

The authors describe the basic concept of switching control in CTRON. CTRON is a set of OS (operating system) interface specifications for information and communication services, and consists of two parts, basic OS and extended OS. The switching control function is defined as one of the extended OS functions, and at present specifications for ISDN (integrated services digital network) circuit switching and packet switching are provided. These specifications include processing for the Q.931, Q.76x, Q.77x, and X.25 protocols, and a speech path control function, which are used by switching processing applications that perform functions such as translation, routing, and billing. Functions for fault tolerance and management are also specified. These interfaces are expected to be used as common OS functions in a wide range of communications