bcm 450 6.0, all phones ringing at the same time?

[Wallysworld]

1st: all patched up
2md: no, the phones are not programmed with "ring and appear"
3rd: every once in a while, randomly, all 100 phones ring with 1 looong ring and then goes quiet.
4th: it is plugged into a ups

I am thinking it is some kind of stray voltage coming in through the phone lines (16 analogue lines)? is there some kind of monitoring device to monitor the voltage of the inbound phone lines? as this is random, I can't sit onsite holding a voltmeter to it waiting to see if the voltage is going to spike.

Perhaps, I am way off base...

Any and all suggestions are welcome.

Thanks

 

[Wallysworld]

Forget it...
systems been working for months and now,
the D@mn buggy bcm changed all my target lines to ring only on 1 extension... for no reason other than to be contrary.

Apparently, I was way, way off base.