interoffice signaling

…another central office (requiring an interoffice call). If the call is intraoffice, the central office switch will handle the entire call process. If the call is interoffice, it will be directed either to a nearby central office or to a distant central office via a long-distance network. In the case…

Interoffice signaling also has undergone a notable evolution, changing over from simple “in-band” methods to fully digitized “out-of-band” methods.