3cx doesn’t see caller hang up (I think)

[combatflyinfish]

Here’s my situation:
I have a relatively newly installed 3cx system on a Win2k8 server. We have 7 analog phones going to two Patton Smartnode 4114 Gateways. The firmware on the Patton’s are up to date as is the 3cx and Windows OS. The specific problem we’re having is when a caller decides to not leave a voicemail within the General Mailbox and hangs up. This is a totally intermittent issue and it’s as if the 3cx doesn’t fully recognize that the caller hung up. So what we end up getting about 1-3 times per day is voicemails with 2 minutes of silence on them.
When I look in the server activity log I will see something like this:
Leg L:618.1[Line:10004<<1234567890] is terminated: Cause: BYE from 192.168.1.3:5060
Then two minutes later I will see the system hanging up the same call from within voicemail. Is there a tweak that can be done so that the system better recognizes that the caller hung up the call?
I know this is a relatively minor issue but everyone knows how end users are about stuff like this and I’m tired of hearing all the whining about it.
Thanks

 

[leejor]

This can be an issue with analogue lines and it all depends on the options offered by the PSTN provider and how you set-up your gateway.

The PSTN customer hanging up first can be detected in one of three ways.

A condition change on the phone line, either er a momentary disconnect (CPC), or sometimes a current reversal, IF, your provider supplies this.

Detection of a disconnect tone, this requires that the gateway is "told' correctly what frequency of tone to detect as this can differ from provider to provider or country to country.

And, silence time-out, usually a separate setting to detect silence in each direction, and to drop the line after a time you select.

The first one, is the best choice as it is just about fool-proof. the next one works most of the time, but can still take a minute to drop the line depending on how soon the disconnect tone is sent. The silence detection is the last resort. Unfortunately, if the settings are not correct, and this may require some trial and error, it can drop low volume calls, or a call when you are on hold and listing to music, so use with caution.

 

[combatflyinfish]

Thanks for your quick reply leejor.
I dug around in the Patton's and found the section of the config that deals with Disconnect signals. There are 4 boxes labeled: Battery Reversal, Loop Break, Busy Tone and DTMF. Of these 4 boxes only Loop Break and Busy Tone are checked off. A little farther down the page there are settings for the Loop-Break Duration: Minimum – 60ms and Maximum- 1000ms
I’m “guessing” but I think I would probably have to adjust theses settings to something else right?

 

[leejor]

Those are the setting although I'm not sure how the DTMF option works. It may be offered in some countries, but, I'm not familiar with it.

The loop break (also called CPC or loop disconnect) option is best if it is supported by your provider. If it was checked, and didn't work, then your PSTN provider may not be offering loop disconnect, or, your settings may be such that it is just not recognized. You can probably contact them to confirm what option they offer. it may be available, but at an additional cost Battery reversal is usually only supplied on outgoing calls, when the called party answers, there is a change in polarity to start billing. However, it could be used to signal disconnect depending on your provider.

Busy tone should work, but again, you have to put in parameters (if there is a field for that) that match the busy (or disconnect tone) that is sent when you don't hang up but the calling party does. Again, your provider may be able to supply you with those parameters.