atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems NECSL2100

Disconnect Supervision is an analog way of the telco to tell the pbx, voip or key system hang up the lines. Back in the day we used to use ground start lines to stop this very thing. As disconnect got better these were done away with, then came the IADS and EMTA boxes. Because it IS analog these are things that can cause lines to "hang" Most these boxes are "barely (if at all)" bell spec for analog lines. This can be anything from a software issue to a hardware issue AND can happen intermittently because they are busy and these boxes have issues esp with maintaining ring voltage, It's hit or miss just be aware you aren't the only one getting this. This was my solution and seems to work for me and my clients. I have very few clients that use analog lines as we generally deal with people using PRI. SIP in some cases but in Illinois PRI is so much cheaper.

Coral Tech,

Great!!! That helps with the understand a bit better. It is sad that the companies that are installing
these devices are not required by the PUC or FCC to comply to the "Bell Spec's" of yesteryear.
It is (has) been frustrating having installed a new system for a customer and right away there are
issue like this. Trying to scrap the egg off your face while trying to fix the unknown problem that
was not your fault, but the fault of the service provider. And then trying to explain all that to the customer.

Thanks for the extra input. Very helpful.

Have a good rest of the weekend.

Les

When a cable company is in the scenario with analog trunks I was told by tech support to set the dial action table time out transfer to hang up as suggested by Coral Tech
I now use this setting on all installs for the SL and SV systems when cable company is providing analog trunks.

Hi dans,

That certainly confirms it for me.

Thanks,

Les