I've got a DXP which has run unencumbered by documentation for as long as I've been w/ the company. Recently some of the extensions/stations have begun to "fail" (my opinion). The problem seems to be AC noise on the station line. I'm slowly figuring out the programming enough to copy EXT to unused EXT.

The system consists of:
DXCPU-68K, 2 - DXIST-16, 1 - DXIST-8, 2 - DXPCO-LP8

So with this I've got 40 Stations available at 66-blocks, the ability to have 16 CO lines, and all the magic the black box does.

Q1: Why might I have AC hum on STA wires? How might it have developed and how might I get rid of it?

Q2: Whilst the DXPIST's are run to the 66-blocks it appears that I only have EXTs from 133-159 (27 out of 40?), how might I go about activating/testing the others to figure out where else I can move dieing STA's?

Thanks in advance for your time.

Firday at 5pm here. off for a cool frosty... :toast: