Unexplained hangups on POTS lines

I’ve got a site with 2 Sangoma B600 cards that has random, infrequent dropped calls for no determined reason. Asterisk and Hardware logs show absolutely nothing unusual - it appears the call is terminated from the far end. Both Sangoma tech support and Schmooze Support have looked into it.

We’re going to try changing these settings:
RM_BATTTHRESH = 1 (orig = 3)
RM_BATTDEBOUNCE = 16 (orig = 4)
in wanpipeX.conf to see if it helps - maybe the Telco voltage is a little low.

Has anyone else played with these settings and successfully solved issues?

And again I forget that you guys now little about ohm’s law or PSTN The previous post was about the resistance in the circuit, Telcos will normally make sure you are within spec at the demarc/MPOE it is up to you to to extend the circuit with the same cae, you would be surprised that a bad connection will form copper sulphate in the presence of current, this makes it a semiconductor that can spoil your whole day.

Perhaps I should explain further, it’s all about ohm’s law, you need a loop current of at least 15 milliamps on a call (closed loop), if the Battery is low, then our friend Ohm will tell you also you will be dropped, examine your wiring on your 66 blocks and anything you added to extend the loop, pay particular attention to connections that look corroded and punch them down again.

Just a comment from an old fashioned telcom guy, do you have access to a voltmeter? you can get one on ebay for 10 bucks if not, if the open loop voltage on your PSTN line is less than about 45 volts you will have problems, if you have bridged connections on that line, then don’t do that, when the battery drops below 40 volts then your call will drop, This is not VOIP just how the phone system works.

I would really contact your carrier as we were receiving the hangup from your carrier as you already know

I second dicko’s comments, but I wonder if it’s occurring on all of your lines.