CSA T512.2 : M87

Gives additional functional and compatibility requirements for any type of PBX with DS-1 digital interfaces. Also provided is functional and compatibility criteria for digital PBX's with only analogue interfaces. It gives requirements for connections made through a digital switching matrix or involving a DS-1 digital interface that differ from those stated in CSA standard CAN3-T512.1. The requirements of the Canadian regulatory authority, existing plant characteristics and objectives were taken in to account when formulating these requirements.