Common Channel Interoffice Signaling: Technology and Hardware

In the early development stages of this new signaling system the need for an integrated electronic technology approach for new units became apparent. A major new unit, the CCIS terminal, is required for the system operation in No. 4 ESS offices as well as in No. 1 ESS toll and in No. 4A/ETS offices. The thin film, beam leaded integrated electronic technology under development for the new No. 4 ESS design has been chosen for this equipment. Other units required in No. 4A/ETS offices only are based on Dual-In-Line Packages (DIP), printed circuit board and electromechanical elements more nearly matching the technology of that system. This mix of hardware improves cost economies and takes advantage of manufacturing techniques already being employed by Western Electric. Using No. 4 ESS technology in the terminal design minimizes maintenance and administrative complexities in those offices. The design for No. 4A crossbar is optimized for conversion of offices by providing options for converting existing equipment rather than requiring the purchase of new frames. 379