sundance-communications.com/forum Forums General General Telephone & Systems Information Disconnect Supervision

Can anyone tell me how this works and does the disconnect come in many forms?

Also how would I tell or find out if an analog extension has or performs disconnect supervision?

Thanks for any help

If you hook up a volt ohm meter and read the DC voltage you will see it drop off from the 8 to 12 volts you're seeing on off hook battery and go back to 48 volts idle line voltage. You can also use the light on your toner. It will dim on a call than go out and come back bright on idle voltage. This is also called calling party control.

There are different types of disconnect supervision depending upon the line type. In most cases (and the most problematic), supervision on loop-start lines is what you will encounter. For a line or even a single-line station port to provide loop or disconnect supervision is for the line to go dead for about a half second when the calling party hangs up. When I say dead, I mean near-absence of line voltage. This "open loop" signals the equipment that the caller is gone and that it is OK to knock down the call, release a held line, voice mail port, etc.

The easiest way to test is to put a tone generator across the line or extension port, but leave it turned off. The continuity light will show that there is line voltage present. Make a call to that line and make sure that it is answered. Hang up from the calling end and watch the LED on the tone generator. It should go dark for about a half-second after the calling party hangs up. This may take up to 15 seconds or so to occur. If the LED never goes dark, then you are not receiving loop supervision.

Didn't see this. The diconnect supervison comes from the CO not the extension.

I like the hat Ed.

In some PBXs, disc. supervision is available on extensions. From other ext.s, c.o. line, or both. John C.

So if I had analog extensions that don't have disconnect supervision then how do the phones know when to hang up. If one side hangs up and the other stays off hook what triggers the release of the line?

My reason for asking is, I have to integrate with a confer III, conference bridge with analog extensions. From the confer III documentation the bridge needs a disconnect super and it only supports (Loop-current interrupt, Dial tone detection, Reorder tone detection, A-tone, D-tone) I don't think I have to worry about calls into the bridge from telco, because telco will send disconnect Super. But if someone uses a analog extension or a IP phone to call in locally to the bridge, I dont know if the bridge will get the proper disconnect it needs.

I appreciate your comments

What type of system are the analog extensions coming out of? As Lightning noted there are some systems that do provide it.


Ed
if we can all make it to the 10,000 posts will we also get one of them hats......I have a long way to go so I am not too worried yet.

Most PBXs and hybrid key systems give some sort of reorder or dial tone return. Heck, it's choosable on the Mitel SX50! John C.

Don't forget reverse battery.