The Key Service Unit (KSU) for the Electra Elite IPK system provides up to 144 ports and can be expanded to a maximum of 192 ports with the addition of 2 expansion KSUs (Same unit is used as expansion KSU). The P64-U10 PSU (power supply unit), backup batteries, two RCA jacks for external paging and MOH input, three DB9 serial interface are included with each KSU.
Mfr. Part #: 750015
NEC Electra Elite IPK B64-U20 KSU with Power Supply