The keyset cables were typically routed to a wiring closet or wiring panel where the Key Service Unit (KSU) was installed and were terminated on a 66 type punch block, typically a model 66M1-50.
The keyset cables were typically routed to a wiring closet or wiring panel. The Key Service Unit (KSU) was installed. The Key Service Unit (KSU) were terminated on a 66 type punch block a model 66M1-50. This was typically.