To test
the easy way
1. Call in or out to an outside phone (like your cell phone)
2. then put the call on hold of the partner system
3. hang up the cell phone.
if you are receiving the disconnect signal from the C.O. the phone system will disconnect the call
The prove it to the repairman way (if they know what they are looking for)
1. hook up a buttset with polarity lights or a buttset and a toner in paralell that has a red/green polarity light to the line in question so the light is green in an on hook/off hook condition
2. call in and answer with the buttset or call out to a cell phone
3. hang up on the cell phone and leave the buttset off hook and watch the polarity light
within a few seconds "of the far end disconnecting" the light should go off for about a half of a second and return to green
some of the terms th CO use is
COD (like the fish) cutoff on disconnect
CPC called party control
disconnect supervision
open look disconnect
Also you may want to look at Sandman's writeup
https://www.sandman.com/cpcbull.html ~Don~