sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Ring voltage

Got 6 copper CO's going to a customer's ESI phone system. Tested the ring voltage at the back board and at the MPOE and pretty much got the same readings. 88 or 89 on 5 of the lines and 90 on one of them.

The line that I get a 90 reading rings on the system, the other 5 do not. However! All six lines will ring on my butt-set.

What voltage do phone systems need from telco in order to ring?

And can a single-line phone ring with a lower ring voltage?

The answer to the last question is yes. As far as phone systems go I would imagine you have to look at the specs to see what is required.

Most systems will ring at anything greater than 75

I don't know the specs for ESI

I'm pretty sure that 90 is ESI's requirement. Does telco have a responsibility to deliver lines with a certain ring voltage?

If the voltage you are receiving is over 75 volts, you are in very good shape. Remember that a standard AC voltmeter won't give you a true RMS reading for a CO line. That shouldn't matter here. If you can receive ringing on a standard 2500 set with a 1.0 REN mechanical ringer from the CO, that's about all you should need or expect.

Yes, there were FCC mandates for voltages, loop current, etc. but they stopped enforcing those standards years ago. Today, what you get is a crap shoot at best because the telcos rule the roost.

I seriously doubt that ESI's requirement for ring voltage is that specific. One volt? They must allow for voltage drop and compensate for temperature variables in resistance. I'd move the lines around and see if the problem follows the lines themselves or the ports on the system.

My opinion is that there is a problem with the system. Like Ed suggests, put the line that works on the other ports and see what happens.

-Hal

I suspect system programming is not set to ring the other lines.

I switched the system out with another brand new one and the same problem, I have slso swapped lines to different ports, same.

If you guys are saying that 88-90 should be good enough then I'm suspecting RF interference from next door radio station towers.

Will a 2500 set plugged in at the demarc ring on all lines?
Try it a few times just to make sure it's consistent.

Sam

So this is the location with the RF interference?

-Hal

I was just going to suggest that , I had one recently where it would ring my buttset fine but wouldn't ring a 2500 set

turned out to be a CO problem but we needed a vendor meet to convince the LEC