atcomsystems.ca/forum Forums General General Telephone & Systems Information Disconnect Supervision Problems

Lately, when I've been making multiple phone calls back to back, and when I disconnect, and try to make another call, the previous call is still in progress. I know I'm holding down the switchook long enough to disconnect instead of activating flash. I've had this issue before, and it is very irritating because half the time I have to hang up to get a new dial tone instead of waiting and making another call because D.S. is so lousy these days. So usually I have to wait around 2 to 5 minutes before I can make another call. For example this evening, I was checking my voicemail, and forgot I can't enter my password on a 500 set (ha ha) and so I hung up and went into the other room to use the TT phone in there, but the line was still connected. I picked up the phone in time to hear the voicemail say "Thank you!" and disconnect. I tried flashing the switchook, and it did nothing. I picked up again to hear the typical two pop sounds you hear when the other party disconnects, and about 6 seconds of silence followed before I heard two rings and then "If you'd like to make a call.." about twice, so I hung up again, waited thirty seconds and picked up again to hear the ear piercing "off-hook" tones. I hung up and this time waited about 3 minutes, and this time I got a new dial tone. Does anyone know why this happens, and is it an error with the line status scanner at my CO? Any information would be appreciated, thanks!

Have you tested your line for metallic faults?

Or for (foreign) high capacitance?

What ringer equivalence do you have installed on the line?

Have you disconnected all except one phone and made a few test calls?

Or all phones, and made a test call from the NID?

Have you had the LEC do a test of your line?

I'm afraid most of those questions are a little to sophisicated for me, as I'm still a newbie to the world of phones. However I can tell you that I have two 500 sets and an AT&T cordless system with one cordless extension plugged into my home line, and I've only had this problem maybe 3 or 4 times ever but I don't like the idea of having a tied up phone line that I might need for an emergency. I will try making a call from the Network interface when this happens again, which I am unfortunately unable to predict when that will be.

By "ringer equivalence installed," are you talking about incoming ringing voltage or the ringing equivalence of the telephone set? It's getting late so I will have to get back to you tomorrow on this, an sorry for the lack of detail. Thanks for your quick reply!

If you have a toner with a continuity check on it, or a volt ohm meter just look for disconnect supervision at the demarc. Put the voltmeter or toner on the line, place a call, hang up. Very quickly the voltmeter should drop to zero than return to around 48 volts. The lamp on the toner should go out than back on. If this doesn't happen the CO is not returning disconnect supervision. Now this is on plain old pots lines. If you are using some type of IP based lines (cable) they probably don't even know what line supervision is.

Oops- I just re-read my post and I realize it sounds like this happens every time I try to place a call. This actually happens quite rarely but is very irritating when it does... Is this just a minor glitch with the telco's line status scanner? I know there isn't anything wrong with my wiring because this happens very rarely. Thanks for the responses!

Intermittent problems are tough to troubleshoot so don't rule out your wiring just yet. I've found where a spider crawled inside an unused modular jack and was fried by ringing voltage that caused the exact same problem you are experiencing.
That said, I would problably suspect a bad telephone set. The next time you have this happen, unplug your phone sets one at a time to see if this will release the line.

I think that telecom guy10 got it backwards.

Disconnect supervision is SENT by the phone company TO YOU that the FAR END has hung up.

The problem is that YOU are not sending a correct disconnect TO the phone company.

It sounds like BobRobert and ttech are right on the money: the problem isn't CPC related, but rather that your phone is not really hanging up, either due to a bad phone or a jack/wiring issue. A high resistance short in a jack (such as the cooked bug) might not conduct well enough to take the line off-hook, but may conduct well enough to keep it off hook after you hang up your phone. Temperature and humidity can affect the cooked bug (for example), hence the intermittent nature of the problem. Another clue to this would be a loss of volume - how is the audio quality on the line when this is happening?

Jim
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Calling Text Messaging a new technology is like saying that the folks who make Bic lighters discovered fire.

Might also be a failing capacitor in one of the two 500 sets' ringer circuits. Disconnect the red wire coming from the ringer coil from terminal R on the network inside the phone. Put a piece of tape over the end of that wire for now and test the situation for a few days. If this works, you've isolated the cause and this is a fairly easy fix.

Thanks for all the information, but I don't think there is anything wrong with the 500 sets- I've never had this problem before with these same phones at my previous house. The house was built around 2001, so the jacks are all in good shape. Ed, thanks for the wiring suggestion, and I will try that next time this happens. This problem is intermittent and hasn't happened for several days. This happened twice with my brand new AT&T cordless phone twice before it ever happened with any of my many R/D and TT old style desk phones. I will check my phone jacks just to be sure no previously-living creature met it's demise from everybody's friend ringing voltage! Thanks for all the suggestions everyone! Also Ed, since you seem to be quite knowledgeable about phone wiring (what an understatement) judging by some of your posts around the forum, I have an older Stromberg-Carlson R/D wall phone that does not ring- it's probably the capacitor, the phone is about 32 years old... But anyway I will pull it out of my telecom vault (a.k.a my bedroom closet) and take a look at it at some point this weekend. Thanks again everyone!