Apples and pomegranates.

The 551 is a self-contained 4-slot 1A2 KSU. Internal power and pre-wired to accommodate up to ten station cables.

The 584 is not a KSU. It is a 13-slot panel that mounts in a 23-inch relay rack, and needs external power and cabling, and external 66 blocks for the inputs/outputs.


Arthur P. Bloom
"30 years of faithful service...15 years on hold"