I'm having big problem. Customer has one C.O. line only. Line goes to alarm, KSU , maybe somewhere else too?

I have the gate coming into Door King 1875 bypass switch then into CO port 4 on 308 EC card.
Gate can call into the system and line 4 lights up with distinctive ring pattern.
But when customer wants to go off hook on CO line 4 and call down to the gate to activate closure options we get no dial tone until I plug the return side of 1875 bypass switch into an ext. Currently Ext. 22.


This is how it was wired by someone else before I swapped out ACS 308 processor in March 2016.
But before his two 206 cards went belly up last week , it seems that it worked good.
Now I have ACS R6 slot 3, 308 EC slot 1, and Partner Mail VS 5.0 slot 2 in 5 slot carrier.

Because there is only one live C.O. number on premises it seems that when you press line 4 button to call down to the gate Line 1 shows busy red light as I would expect.

But now when calls come in from outside world gate seems to seize the dial tone at certain times and then Ext.22 stays busy and holds the line?
Also some calls ringing in then cause Line 4 distinctive gate ring to be triggered. Apparently these last 2 problems were not occurring before.

Any concrete ideas? Thank you!!

alwayslearning

Telesystems technician