Do you mean you have to replace some cards in the KSU? In basic, general terms, KSU (Key Service Unit) and PBX (Private Branch Exchange) are the same thing, with a PBX being a larger system.


If you are replacing cards in an Elite 192, it depends on which cards you are replacing and what you have to do. Some cards can be removed with the cabinet powered up while some require it powered down. If unsure, power it down first.