analog lines not getting disconnected

[fadhumohammed]

after a call is made from IPphone to mobile(for eg), even after disconnecting the call from IPphone its not getting disconnected on mobile...

inshort the fxo port is still active..the voice port remains off-hook..so gotta manually shut and open voice port from CLI everytime....

tried changing the cptone configuration(tried all the cisco provided configs(erricsson,alcatel etc))

regards

fadhu mohammed

[Aaron Dhiman]

Sorry for the tangent here, but when connecting an FXS to an FXO:

IPphone---CCM----------GW/FXS-----FXO/PBX---DigitalPhone

If IPphone hangs up, should the GW/FXS send a disconnect tone to the FXO port to signal end of call, or does it just of on hook? Also, if the FXO is hanging up, what methods can be tried on the FXS side to force FXO-side disconnect?

[paolo bevilacqua]

Hi,

Yes, when IPphone hangs-up, GW/FXS hangs-up as well, FXO/PBX senses loop open, lshould show disconnects and/or give a tone.

Viceversa, when DigitalPhone disconnects first, either PBX is able to do a power denial or battey reversal, or you must base disconnect supervsion on GW/FXS, based on tone detection.

[paolo bevilacqua]

Actually, I should add something. You should implement disconnect supervision for the second scenario above, only if for some reason you what the IPphone user able to see far-end disconnection. In most cases, this is not necessary, because people agree to end conversations.

[Aaron Dhiman]

I found the document "Understanding FXO Disconnect", which does a good job explaining how to change a router's FXO port disconnect detection; however, it doesn't seem to address this issue where there is no phone connected to an FXS, just a PBX/FXO port (which I do not have access to configure):

Scenario 1: PBX phone hangs up and its FXO port goes on hook. Now, the router's FXS port should detect loop open/on-hook. I imagine this is working fine.

Scenario 2: IP phone hangs up and the router's FXS port signals battery reversal to indicate the end of the call. I think here that the PBX must not be detecting this properly. If I disable "battery-reversal" on the FXS port, what method will it use to signal the end of the call then? I imagine I'd also have to get the PBX administrator to re-configure his side as well then?

[pcameron]

For scenario (2) - you now understand the fundamental limitation of using FXS and FXO ports to trunk between PBX's. Since the FXS port on the router expects the attached device to physically drop the loop, all it can do is either play a disconnect tone or reverse the polarity of the line to indicate the call has cleared.

If the atached device does not support either of these methods , then ... it's working as designed :-)

This is precisely the reason why E&M interfaces were developed for interconnecting PBX's. The E&M interface has audio pairs (TX and RX) as well as control leads that give an indication of the state of the call in either direction. This way, if the PBX or the router drops the call, the other side sees the control lead change state and it knows the call has ended.

This is known as end to end call supervision, which basic FXS/FXO does not provide.

The best way to connect PBX's is using analogue E&M trunks, ISDN BRI or PRI. trunking with FXS and FXO is not a good solution.

Refer here for more details on E&M trunks -

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a0080093f60.shtml

http://www.cisco.com/en/US/products/hw/gatecont/ps2250/products_tech_note09186a008009452e.shtml

[Aaron Dhiman]

Great post, gave you a good rating. Thx.

[maher_miniesy]

Dear Sir

I have the same problem wity many customer can you help me how can use this software ( Cool Edit Pro ver2.1)to know frequency and cadence

Thanks, Regards

Mohamed Maher

[paolo bevilacqua]

Hi,

to know the frequency used in you country without analyzing frequencies, go to:

http://www.3amsystems.com/wireline/tone-search.htm

Hope this helps, please rate post if it does!

[fadhumohammed]

yes..u can analyze the fxo disconnect tone manually..jst follow these steps..

1. get the wireshark log

2. analyze->decode to RTP file

3. statistics->RTP->stream anaylse

4. save as .AU file

5. open the au file with cool edit pro

6. measure the off time and on time gap(in time)=cadence

7. in cool edit pro, analyse->frequency analyse

8. for each off and on time measure the peak frequency and tats the frequency

guess this should help!!!!!....

[maher_miniesy]

Dear Sir

Thanks for replay, i made this steps but can't export the frequency and cadence from graph can you help me to export it from cool edit pro or send me examble for that by eamil also my email is maher_miniesy@seegypt.com

Thanks , Regards.

[hoanghiep]

An easier way to record the tone is to use IP Communicator!

I've used IPCommunicator and got the right results!

[pcameron]

Hi Maher - if you can post a wireshark capture of the local disconnect tones, I will write up a detailed note on how to analyse the tones and publish it here as question keeps coming all the time !

[ita_hsieh]

hi I have upload the disconnect tones, could you please provide detailed steps on how the analyze the tone? Thank you very much.

regards

Alex

[paolo bevilacqua]

Where are you located? Begin with the tones detailed at www.3amsystems.com.