atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Sparky, it wasn't you, this time!

Got two almost simultaneous calls a few days ago.

1. My friend at the local alarm company called to ask me to make a visit to see why his daily tests were being sent and received from a commercial occupancy, but he was unable to dial in after-hours to do some system program housekeeping.

2. The owner of said occupancy called to ask why (I am translating from Customer-ese to Telephone-ese) when his first CO line rings up, the third CO button also rings up, and similarly, why when CO line 2 rings up, the fourth button also rings up.

Hint: Verizon was there a few days ago.

Anyone care to guess what happened? "Let's not see the same hands, class..."

Split pairs?

Must be something wrong with your PBX!

tick tock.....

I know I am going to love the right answer and I can almost see this in my mind's eye. My guess is he rewired the alarm jacks somehow.

The customer's wife, unbeknownst to the owner, decided to save money and have two of the four voice lines disconnected. They happened to be the two lines that fed the commercial alarm system (requires two CO lines.) They were lines 3 and 4 on the system.

For some reason, Verizon actually showed up to do the disconnect (unheard of even back when VZ knew what they were doing.)

The VZ "technician" removed the 1st CO pair going into the alarm panel from the now-dead NID terminals, and paralleled them onto the 3rd NID terminals.

Then he did the same thing with the wiring for alarm line #2 (putting the pair in parallel with the line #4 terminals.)

Result:

The alarm would dial out ok, but the line-seizure feature was compromised on both lines. The VZ guy apparently was not familiar with line-seizure wiring, and just paralleled the "in" alarm wires with any old dial tones he could find at the NID. The alarm company programming operation was reaching two lines that are on intercept, therefore, not able to get into the panel.

Since the "out" wires of the two RJ-31X jacks used to feed CO lines 3 & 4 on the key system, they now were feeding line #1 into button #3 and line #2 into button #4, causing a pair of buttons to ring up in parallel each time there was an incoming call. A case of "double dial tone" with a line appearing on 2 buttons rather than 1 button.

Electrically, there was no fault that would have generated a trouble ticket, just confusion on the part of the innocent customer, and on the part of the guy who was sent out to fix it (me). Just when I thought, after 50 years of doing this, that I'd seen everything.

Yep, I love the answer!

A classic......


Sam

Wow...