Common Channel Interoffice Signaling: Implementation Planning

Common Channel Interoffice Signaling (CCIS) is being rapidly introduced throughout the toll network of the Bell System. At present, CCIS is part of every No. 4 ESS office, and many existing 4A crossbar offices with Electronic Translation System (ETS) are being converted to CCIS. In addition, CCIS is being developed for No. 1 ESS and No. 1A ESS toll switching offices, and development is under way to extend CCIS to Traffic Service Position Sytems (TSPS). Exploratory studies are also in progress to extend CCIS to No. 1 ESS and No. 1A ESS local switching offices and to No. 5 crossbar-ETS, No. 2 ESS, and No. 3 ESS as well as to DIMENSION® PBXs and other PBXs.