atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Loop current/ high audio level

I opened a ticket with verizon we will see what happens. I have 30 ShoreTel customers and 3/4 of them use analog lines to some capacity, not a one has this issue. Could something in the CO cause this issue, like a bad card or something??

I'm at my wits end, I even ajusted the trunk gains in the database to see if that would help, nothing.

If it's not doing it from the DEMARC it's not Verizons trouble.

It's not out of the realm of reality that the high loop current is causing the problem. Esp. if there is a transformer interface to the C.O. line. But, as has been already pointed out, high loop current is not a concern of Verizon, or any other LEC. I suspect that if you take a DC voltage check on-hook, you'll find something in the neighborhood of 52 Volts DC, rather than 48 Volts DC. Remember that the LEC would like to have a high enough voltage out of the central office to support communications out several thousand feet. Resistance being what it is, and the need to maintain 5-7 Volts DC off-hook, they start out high. Your problems probably will go away by getting your off-hook voltage down to 5-7 Volts DC and your off-hook current down to 28-35 milliamps. The LEC is not going to do it! It's your problem, they're within their spec!

Try this, put a 100 ohm, 1/4 or 1/2 watt, resistor in series with the tip lead and another in series with the ring lead. This will drop off-hook voltage and current, although probably not enough. Next steps would be 220 ohm and 330 ohm.
You must put equal resistances in the t and r leads in order to maintain longitudinal balance, don't cheat. This may reduce audio too much, if so try a .47 uf 200 volt non-polarized (no plus or minus sign on the capacitor) capacitor in parallel with each resistor. All these parts used to be available at Radio Shack. But, they've been cutting their component inventory, so you may have to go elsewhere. DIGI-KEY would be a choice, but they have a $20? minimum and these parts won't be more than $5, even at R/S prices.

While I agree that you can lower current and voltage as you describe Lightning, I have never seen a condition affecting voice that couldn't be duplicated at the DEMARC with a butt set. I'm not talking about high loop current affecting the key equip, modem or whatever, just what the OP has discribed, voice clipping.

I call Verizon and had a tech on-site, he read the 50ma and said what do you want me to do LOL!!
Asked if he could walk to the CO and see if they could do anything about lowering the loop current, guess what they said, pack sand. That was to be expected, I had to try.

Can you old school guys tell me what I need to buy as far as components (resistors/capacitors) that will drop the current down and maybe the db too.
I at the point I will try anything, even if its a long shot.

Re-read the 2nd paragraph of my last post. Ask specific questions based on it. John C.

Ok, so I will get two 220 resistors and put them inline with tip and ring. Where is the best place to get those?? I will install those inline and post my findings.

If you're going to lower the loop current get the ones from Sandman. They keep a constant current no matter what the phone company throws at you. With resistors you'll have to experiment until you get what you want and the conditions could change.

I'm going to say this once more to maybe get through. High loop current will not cause clipping.

Bill has the best idea. Resistors are cheap, but things could change and throw all your hard work out the window.

Bill, I'll agree that the loop current itself is not directly the problem, it's the inability of the equipment to cope with it. It's a design problem.

There-in lies the problem. They are trying to reinvent the wheel instead of adhering to the established standards.