Weird analog issue :-/

[thephonelady]

Hi all- Here's a weird issue- IP500 running 9.1.
Slot 1 Combo
Slot 2 Did 8/ ATM 4
Slot 3 Dig 8/ ATM 4
Slot 4 Pnone 2/ ATM4
Issue started with lines on Mod 1 showing OOS and no lights on line ports. Power cycle cleared issue and restored lines.
Happened again a few months later. Power cycle restored service. Issue only on Mod 1. None of the digital stations were affected.
I moved the lines around to spare ports leaving only one of the original lines in the moduls on Port 4. Ports 1-3 had the users first 3 main lines.
Fast forward a few months. Same issue on Modules 2 & 4. Power cycle cleared the issue. Happened again. Power cycle clears the issue. System Status always shows the line ports OOS. Went to site and moved the first 3 lines and 1 other to Mod 1. Two days later Mod 1 lines are not working and show oos and no leds on the line ports. Digital stations are fine.
The trouble seems to follow where I am moving the lines. Frontier lines that are grandfathered from Sprint- Frontier has issues finding records on the lines.
Could there be some foreign voltage affecting the line/ lines and causing this issue?? The system is grounded and plugged into a UPS
Any thoughts are welcome.
Thanks, Eileen

 

[RocketJTech]

One possible issue could be high loop current. Some IP500 cards do not like a loop current higher than 35-40 mA. The card gets too hot and shuts itself down. Usually, if this is the problem, prior to shutdown, the user may hear static on one or more lines, or may experience dropped calls, as the ports try to reset. A reboot causes the card to reset and will be good for awhile (weeks or months). The line provider will tell you that the loop current is within standard (which is technically true, if it's below 80mA). However, this standard was developed when the central office had thousands of feet between itself and the subscriber. With the development of multiplexers, fiber and cable modems, the "Central Office" is now in your back yard (or your data closet)and no longer has the resistance of all that cable. I have been successful in getting the provider to turn down the loop current, ONCE, but good luck if you decide to go that route. I've found it easier to knock it down myself.

You can test this with most Volt/Ohm meters by moving the red lead to the unused port, switching to the appropriate setting, and opening one side of your pair, running it THROUGH the VOM. Go off hook on the line using one of the system phones. Also, some of the higher-end butt sets will measure it by just going across the pair.

I think the newer IP500 cards have been "beefed up" to prevent this, but don't quote me on that. I just know that, while I had these issues many times in the past, they seems to be fewer and farther between the last couple years.

If you find that your loop current is too high, you can bring it down using resistors. However, I recommend line conditioners. Sandman and Viking both have models that I have used. There are others on the market as well. I think the Sandman model uses resistors, but the viking model takes whatever the input current is and outputs it at 25mA, which is about perfect.



Sometimes, I feel like a kindergartner missing out on recess, because certain kids won't shut up and get in line.

 

[critchey]

Check the PCS of the control unit. There was a PSN for PCS versions 18-21 for "noise on the lines" but I found it to cause far more issues then just noise. If your PCS does fall between 18-21 just replace the control unit. I am fairly sure this PSN happened in the R9.1 days that is what made me think of it.

The truth is just an excuse for lack of imagination.