Incoming calls to SPA3012 do not disconnect when I hang up

[dreamscape]

Hi

I have calls succesfully routing through the SPA3102 but find that on receiving calls, if the caller does not hang up, the line stays open. If I call out to the PSTN line and I end the call, the call ends automatically on the mobile phone. Is this a problem with the regional settings on the SPA3102, or the SPA504g which I am using?

Kind regards

Mark

 

[eagle2]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Try changing port impedance, polarity reversal detection, CPC, idle disconnect time, disconnect and/or busy tone, etc. Look in forums on SPA-3102 like Voxilla, etc. You may find information regarding your specific provider and advice how to handle it / combination of settings.

Non disconnecting is common problem and is mostly related to your PSTN provider and not to the IP PBX itself, in your case 3CX Phone System.

Regards.

 

[leejor]

Re: Incoming calls to SPA3012 do not disconnect when I hang

I would not change the port impedance from the default unless you are not located in North America, or, you have echo problems, it won't affect disconnect issues. the other options mentioned, will.

 

[eagle2]

Re: Incoming calls to SPA3012 do not disconnect when I hang

I would not change the port impedance from the default unless you are not located in North America, or, you have echo problems, it won't affect disconnect issues. the other options mentioned, will.

I agree Leejor, normally you should not change port impedance in North America.

I depends on provider entirely, I came across some sites in Internet stating recommended impedance and tones for different countries. My personal experience (I have installations in several European countries) is setting impedance to 'Global' is fine in most cases (at least better than default '600 Ohms' or locally recommended 220+820|120nF), otherwise I'm experiencing unexpected hangs, like non-disconnecting, etc.

If you are connecting SPA-3102 to host PBX (analog extension ports) or analog GSM gateway device, you may also need to adjust parameters.

BR

 

[dreamscape]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Thanks for that information.

I live in the UK and have changed the impedance to both settings inline with http://www.aoakley.com/articles/2008-01-08.php who seems to give a pretty good explaination and alot of posts in other forums quote his page.

I have also read on the Cisco forums this morning about downgrading from the latest firmware. 5.1.10 to 5.1.7, but this seems to be with regards to the SPA3102 not disconnecting at all.

I have setup the SPA504g to the same regional settings as the SPA3102, is this correct?

Kind regards

Mark

 

[leejor]

Re: Incoming calls to SPA3012 do not disconnect when I hang

The regional settings of the 504g can be whatever your preference is. (what you want the tones and ringing to sound like). It is not connected to the phone line, only the FXO port of the 3102 is. That ports settings will vary, depending where in the world the 3102 is installed.

 

[dreamscape]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Thanks for that Leejor

Would you be able to provide any advice on gain settings for the SPA3102? I seem to have an issue with echoing if both parties talk at the same time during a call. It only concerns the 3CX side and not the outside caller.

I have played around with the 3 echo settings and all 3 need to be on to stop the 3CX end user echoing with just themselves talking.

Many thanks

Mark

 

[eagle2]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Gain settings should be kept lower - good value is either -3 or 0 dB. Putting higher (positive) value will create echo problems. Also port impedance on FXO port is related to echo. Try also reducing outgoing (i.e. SPA to PSTN) gain and increasing incoming (i.e. PSTN to SPA) gain, with at least a difference of 6 dB, if the party can still hear you well.

 

[dreamscape]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Hi Eagle2

I think I found one of your posts after I put this up. Thanks for your reply.

I have been researching in combination with what you are suggested, changing the actual SPA504g gain as someone on one of the cisco forums seemed to think it may be necessary (although it was in reference to a different cisco series phone)

I have found this post, http://www.dslreports.com/forum/remark,15664687, which I thought was quite interesting in regards to changing the RTP packet size. I am not using any voip providers at the moment so I presume that I shouldn't have any bandwidth problems as the ISP is not involved?

I'll have to wait until the end of the day to be able to do some testing and i'll report back thereafter.

Mark

 

[eagle2]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Hi Mark,

smaller RTP size generally increases quality and bandwidth used. Default for Cisco/Linksys phones is 30ms, while 3CX recommends 20ms (in manual settings for Linksys, as well as set automatically by autoprovisioning also). I also prefer to use G.711 codec wherever possible - this always provides better voice quality. With G.729 codec normally you need also to increase gain at least with 3dB to have similar level.

Kind regards,
Orlin.

 

[dreamscape]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Hi Orlin

So would you recommend the 0.01 RTP setting with G.711?

Unfortunately I haven't done any testing as yet but will have by the end of the weekend.

I'll test all ways and report back.

Many thanks

Mark

 

[leejor]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Here is an interesting "discussion" on reducing packet size, and the trade-off, bandwidth.

http://www.dslreports.com/forum/remark,15664687

 

[SY]

Re: Incoming calls to SPA3012 do not disconnect when I hang

It is also interesting
http://www.3cx.com/blog/docs/bandwidth-dsl-atm-isp/

 

[Cjay]

Re: Incoming calls to SPA3012 do not disconnect when I hang

on receiving calls, if the caller does not hang up, the line stays open.

This this topic has gone off in an interesting direction, but the original question got me thinking!

As the OP is based in the UK (and I will assume on a BT PSTN line), then it is perfectly true that if an incoming PSTN call that routes PSTN --> SPA3102 --> 3cx/VoIP phone is terminated only by the receiving party (so the caller stays on the line, but the called party [i.e. the VoIP phone] hangs up), then the PSTN leg of the call will not clear down for something like 90 seconds. The consequence of this is that if you try and make another outgoing PSTN call in this 90 second window then the SPA3102 will not get dial tone when seizing the line and so gives an error message (though if you were to pick up a conventional analogue phone bridged across the line then the original caller would still be there and conversation could continue). This was sometimes used for malicious purposes in the past where the line would hold indefinitely, but I think modern exchanges clear down the call after a timeout period - 90 seconds in my case.

Chris

 

[leejor]

Re: Incoming calls to SPA3012 do not disconnect when I hang

A problem should not occur when the VoIP phone (the 3CX extension) hangs up first. In that case a message should be sent to the 3102 telling it to drop the line. I say should because, as we've all found on occasion, what should happen , doesn't always work the way it is supposed to.

The problem is that if, for some reason, that release message is never sent from 3CX to the 3102 andthere is no other PSTN disconnect method (CPC, disconnect tone, silence detect) in use, then the PSTN line will be held up indefinitely, in theory.

This scenario could be caused by a forgotten parked call, one left on hold, a handset placed on a desk and forgotten about, or a possible "glitch" in the system.

The best method to use is CPC (that is a momentary disconnect on the phone line provided by the phone company), it is the most reliable, but is not available to all customers. The next choice is the disconnect tone (or a combination of the two, just to be sure), and the fall back/last choice is silence detection (the last option usually allows monitoring in both directions). In some cases the phone company will provide a current reversal when the called party answers, if the gateway supports it, that can also be used, but generally only on outbound calls.

Silence detection can be used as a backup to the other two methods, but if you choose to do so, set it to about 10 minutes (or even longer). I've found that when placed on hold, the background music may not be loud enough to be detected, and the call will be disconnected prematurely.

Just my two cents worth...

 

[SY]

Re: Incoming calls to SPA3012 do not disconnect when I hang

3CX Phone System always notifies about termination of the call. No exceptions

 

[eagle2]

Re: Incoming calls to SPA3012 do not disconnect when I hang

Hi Orlin

So would you recommend the 0.01 RTP setting with G.711?

Unfortunately I haven't done any testing as yet but will have by the end of the weekend.

I'll test all ways and report back.

Many thanks

Mark

0.01 will increase the bandwidth too much
0.03 is the default value, 3CX recommends 0.02 as setting, which is better quality
from my experience I recommend G.711a/µ instead of G.729a where available bandwidth permits -- voice quality is higher, moreover the number of G.729 licenses is limited