FXO ringing problem

[hiepnguyenho]

Dear all,

I dial by mobile phone from PSTN to my company number and press the extension number for local phone. The IP Phone rings. Now I hang off the mobile phone but the IP Phone still ringing. So what is the problem? Is it caused by FXO setting? Thank you very much.

[Dennis Mink]

You might want to check the following document

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800ae2d1.shtml

this deals with FXO disconnect supervision

(please rate)

[Harmit Singh]

Hi,

As pointed out by Dennis, this sounds like a supervisory disconnect issue. This problem is seen only in FXO - Loop Start (FXOLS) lines.Please ensure that the correct CP Tone is applied on the voice-port. By default, it is US. If the router is in another country, then you would need to apply the correct CP Tone and shut / no shut the port(s). See if that helps. Also, go through the document provided earlier and try the commands suggested:

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800ae2d1.shtml

Else, there are a few ways to go about it:

++     Talk to Telco and get the line converted to FXO - Ground Start.

++     Get rid of FXO and get an ISDN PRI / CAS.

++     Create custom CP tone with the disconnect frequencies and cadence values either provide by telco or with the help of a PCM capture. If you need help with that, let me know and I can provide the steps to capture that output. This method may or may not fix the problem based on my exprience.

Please rate if helpful.

--

Harmit.

[hiepnguyenho]

Dear Harmit,

I'm from Vietnam - the non-standard country . I have my custom cp-tone for the voice-port but it works not very well. It can disconnect the voice port only when 2 parties on hook. It can not solve the problem as I described in this topic.

So please tell me how to do a PCM capture and get the right frequency. Thank you very much.

[Harmit Singh]

Hi,

Apologies for the delay. Here is what you would need to do while recreating the issue:

Please configure the following:
conf t
voice hpi capture destination flash:pcm.dat
voice hpi capture buffer 5000000
exit

>>at this point you need to figure out exactly which voice port you are on and you issue the following command:

>>test voice port 0/0 pcm-dump caplog 7
--------> assuming the call will go out from / come in on the 1st FXO port. Its best you do it after hours to avoid the confusion. You can even issue "show voice call status" to verify which port is used 1st if you arent sure otherwise.

>>once you are done talking and capture enough of the static:
test voice port 0/0/0:15.1 pcm-dump disable
conf t
no voice hpi capture destination flash:pcm.dat
no voice hpi capture buffer 5000000

Its very important to remove the above commands else they keep writing to the flash and will eventually crash the router.

>>Now do a dir flash: and you can see a file "pcm.dat" that's the file I will need you to send me so I can analyze. Remember if you do this more than once, remember to always delete the pcm.dat file so we don't >>have calls overwriting each other and things getting mixed up.

--

Harmit.

[hiepnguyenho]

Hi Harmit,

Thank you so much. Tomorow I will capture the PCM and send back the .dat file to you. Much appreciate!

[hiepnguyenho]

Dear Harmit,

Sorry for late. Please find the attach for pcm.dat file and please help me to analyze it. Much appriciate!

[Harmit Singh]

Hi,

I decoded and analyzed the PCM capture. Try the following and let me know if it helps:

++ Under Global Config Mode --

voice class custom-cptone FXO
dualtone disconnect
frequency 415 440
cadence 516 484

++ Under the FXO voice-port --

voice-port 0/1/0                                                -----> Assuming this is the FXO voice-port
supervisory disconnect dualtone mid-call
supervisory custom-cptone FXO

++     Do a shut / no shut after applying this config on the voice-port and this would need to be done on all FXO voice-ports as well.

Do let me know if it helps in resolving the issue.

--

Harmit.

[trungfotech]

Dear Harmit,

I'm from VietNam, the non-standard country, So I have a problem same as Mr. Hiep. In my country, in each district or with each telephony service provide have a difference standard for telephony service, we are very hard for cover all of standard, no document, no any help from telephony service for this problem. So we must manual determine the disconnect tone in relative state, not exactly for all voice gateway for  all regional.

As Mr. Hiep discussed, I have a problem with frenquency and cadence in voice gateway configuration, the problem same as mr.Hiep, can you have me analyze my pcm.dat file in attach file, or can you provide for we a method or any help for us to analyze oneself for another case of this problem.

I have tried your parameter which you analized for Mr. Hiep, but it not work in my district.

Can you have we to resolve this case ?

Thank you very much,

Trung.

[hiepnguyenho]

Dear Harmit,

The problem is still occur.

When I dial from PSTN to the extension number. While the extension is ringging, I hang up. The extension is still ringging and can not end.

Is there any solution for this? Thank you very much.

[Harmit Singh]

Hi Hiep and Trung,

Sorry for the late reply, i've not been around lately. Is it possible for you to get the frequency and the ON and OFF cadence values from Telco?That would help us configure the custom CP Tone.

--

Harmit.

[trungfotech]

Dear Harmit,

We have asked with Telco, but they reply very lately . Can you provide for us the method for manual detect frequency and cadence with pcm.dat file ? Because I will deploy voice gateway with FXO Card in 30 branch, the Frequency is not same in all branch, so I need to manual detect frenquency and cadence. The Telco is not ready for support us in this case.

Thank you very much,

Trung.

[Harmit Singh]

Hi Trung / Hiep,

Apologies for the delay in response, it's been a crazy week at work. The PCM.DAT file needs to be extracted using an internal tool we have in Cisco, which means that you would have to send it to someone in Cisco to extract the files from it and then analyze it using cool edit or adobe audition to get the frequencies and cadences. There are a DDTS that i found in the DSPWare of the IOS, not sure if you may be running into that after applying the custom cptone: CSCsu68373. Kindly ensure you are running a fix IOS version for that DDTS.

I would request you both to make the following change to the config and try again:

++ Under Global Config Mode --

voice class custom-cptone FXO
dualtone  disconnect
frequency 425
cadence 500 500

++ Under the  FXO voice-port --

voice-port  0/1/0                                                -----> Assuming  this is the FXO voice-port
supervisory disconnect dualtone mid-call
supervisory  custom-cptone FXO

++     Do a shut / no shut after applying this config  on the voice-port and this would need to be done on all FXO voice-ports  as well.

Let me know how it goes.

--

Harmit.

[hiepnguyenho]

Dear Harmit,

Thanks for your help. I have tried a more simple way as described in Cisco forum. I captured  RTP payload by Wireshark of the inbound call from PSTN and cut the disconnect tone from this wav file.Then I used CoolEdit Pro to analyze frequency and cadence. The result is good, I think.

For this configuration, I add one more line and it works.

voice-port  0/1/0                                             
supervisory disconnect dualtone mid-call
supervisory  custom-cptone FXO

time-out wait-release 1 (without this, it takes the default value, 30 second to disconnect ringing)

Thanks again for your help.

[Harmit Singh · Accepted solution]

Hi Hiep,

Thank you for updating everyone on this post. I'm glad to hear that its working fine now. Incase anyone is wondering what the "timeouts wait-release" command does, it is used to configure the delay timeout before the system starts the process for releasing voice ports. From the command lookup tool, the usage guideline states: Use this command to limit the time a voice port can be held in a call  failure state. After the timeout, the release sequence is enabled.

--

Harmit.