Abstract :
The author describes one particular but important enhancement needed to GPT´s equipment to meet the needs of an armed forces customer, being the need to signal information specific to these special military requirements across the network. He describes the investigation of signalling system standards available at the time of inception of the project, the enhancements made to CCITT No. 7 common channel signalling to meet the customers needs, and pertinent practical information about the implementation and use of specially enhanced signalling systems. The backbone of this system is an extensive network of PABXs
