atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems DSX 40 Disconnect Supervision

I have a DSX 40 using station forwarding to a cell phone. A call comes in after hours through the attendant and when the station is dialed it forwards to the cell. The call ends and the parties hang up. However, no disconnect signal is reaching the DSX and the lines hang open until they are manually reset.

Verizon is asking the following:

1) What kind of disconnect signal is the system looking for?
2) Is it waiting for called party disconnect, calling party disconnect, or first disconnect?
3) Could the cell phone be the issue in not registering the disconnect?

The customer is getting fed up with there being no resolution to this issue, so any assistance is GREATLY appreciated.

Stacey:

1) You are requesting open loop supervision, otherwise known as loop supervision, COD or CPC. If working properly, the line goes dead for about 1/2 second when the calling party hangs up. This signals the DSX to drop the call (assuming that it's configured to do so).

2) First disconnect is best, but called party is a good second choice. That way, any toll charges associated with the forwarded call end promptly.

3) This issue has nothing to do with the cell phone or the cell carrier. It's all associated with the end office, i.e: The central office serving the customer's site.

Honestly, you shouldn't even have to answer these questions to Verizon, but we'll save my comments about that for another day. Don't forget that despite the fact that the central office may be sending the disconnect signal (they will always tell you this), pair gain equipment is often not configured properly to convey this signal to the premises. You really need to press this issue with them because the drones at the computer terminals see that it's programmed. That's as far as they are willing to go. "Must be something wrong with your PBX" is their canned response.

This link might give you some info you coul;d use to resolve this disconnect problem:

https://www.sandman.com/cpcbull.html

Since I have a number of DSX-40s installed, I am very interested in a resolution here. Please let me know if this works for you. I have similar applications that I have not programmed yet.

Thanks,

Al Dukes

:shrug:

Oh yeah, as an added note, Ed is right about pair gain equipment. I am also agreeable with him regarding having to respond to telco's questions as to what is expected. The problem is definitely in the C.O. At least as I see it. Good and solid, Ed! Thanks.


Al Dukes
:bang:

Wow. Thanks for the quick responses! This MUST be resolved next week and I will be sure to let you know the outcome.

Although a sometimes a pain for the customer (Having to dial 9 for outside calls) but this is where good old centrex service comes in.

With the centrex transfering the call the phone system is no longer in the picture.

Some LEC's do have a feature called "Call transfer" that can be put on a per line basis. Dont confuse this with three-way calling as that is a completely different can of worms.

And as stated above you may have to do some detective work to see if you are actually getting a disconnect signal (momentary open circuit of at least 800-1000 ms)when an incoming call is answered by the system and the outside party hangs up while you stay on the line.

If the DSX is programmed properly, an easy way to check for disconnect signal is to call in via your cell phone, answer the call on the DSX, put the call on hold and then end the cell phone call.

If you are getting immediate disconnect the held call will drop in a few seconds. In many of the old GTE/Verizon CO's around here you will get a disconnect after about 3 min.

DJ

daaaa you want disconnect hang up the phone, thank you for calling tech support

Heh...we had fun with a couple of our lines. We weren't getting the disconnect supervision (I've seen this sort of thing before, but getting talk-america or SBC to do anything about it...well, I'll follow Ed's cue.)

At any rate, the AT&T tech told me she had never heard such a thing. But to her credit, she asked around. She told me it was a "translation issue" that had to do with Siemens switches.

Oy vey!

The new news is that this customer is being fed off a slick and there are similar problems with other businesses on the street. We're trying to get through to the mysterious "engineer" that the tech keeps talking about. Vz already put in a new card 2 weeks ago to fix spontaneous ringing on another business' lines, so they won't look at replacing that again.

I doubt that the card in the SLC is actually bad; it's just not optioned correctly. They are notorious for replacing them right out of the box without configuring them to repeat the disconnect signal.