Can't hear the other person at the end of the line on PSTN calls

Answered Question
Sep 7th, 2010
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Hello Y'all

I am having problems hearing the other person at the end of the line on pstn calls. The CME has a VIC2-4FXO module and I have the PSTN connection trhough voiceport 0/0/0


The pstn calls terminate on ephone1 which is configured with connection plar. It rings ok both ways both cant hear a thing when the call is picked.


I have done a debug of the ephone detail (Please find debug output and CME running config attached), I notice that after start media (which is when the phones are suposed to start exchanging RTP), there is a message which shows NO LOCAL PHONE MATCH FOR START MEDIA.


I think therein lies the problem(though i am not so sure)


Would really appreciate any help.

Thanks,

Yomi

Correct Answer by Steven Holl about 6 years 10 months ago

No worries.  Also we should note that if you have FXO trunks on CME, transfer isn't supported:


PSTN FXO Trunk Lines
...
Calls placed to or received on an FXO line have restricted Cisco Unified CME services and cannot be transferred by Cisco Unified CME. However, phone users are able to access hookflash-controlled PSTN services using the Flash soft key.


I'd recommend you use the IP PBX mode instead of trunking phone's DNs directly to the FXO port.  It's more flexible.  You can use line monitoring or phone watching to have users know if everyone is on the phone.

Correct Answer by Rob Huffman about 6 years 10 months ago

Hi Yomi,


Try



ephone-dn  49   dual-line
number 012701062
trunk 49
!
!
ephone-dn  50   dual-line
number 012701061
trunk 50


Cheers!

Rob

Correct Answer by Steven Holl about 6 years 10 months ago

You need to configure 'ip routing' globally.  That is the default configuration--someone configured this box and added 'no ip routing'
which is a misconfiguration and breaks voice traffic.

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Steven Holl Tue, 09/07/2010 - 08:42
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You have 'no ip routing' configured, which prevents audio from being routed to the DSP.


Configure 'ip routing' and re-test.

Abayomi Smith Wed, 09/08/2010 - 06:05
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Hey Stephen,

Thanks a lot for your response.

Sorry for the bother but I am not so clear on what you said about configuring ip routing.Do i configure ip routing globally or  do I have to configure ip routing to the dsp specially?if so, how is this done?

Thanks

Correct Answer
Steven Holl Wed, 09/08/2010 - 06:21
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  • Cisco Employee,

You need to configure 'ip routing' globally.  That is the default configuration--someone configured this box and added 'no ip routing'
which is a misconfiguration and breaks voice traffic.

Abayomi Smith Wed, 09/08/2010 - 11:17
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Hey Steven,

Thanks a million, It worked.

Got two-audio now and can hear clearly.

However there is an additional issue, which is being able to transfer the calls from that line to other ephones connected to the CME.


The calls are terminated via Private Line Automatic Ringdown, however i have learnt this limits the features(such as call transfer etc.)


What is the work around and how do I implement it?


Many Thanks,

Yomi

Steven Holl Wed, 09/08/2010 - 11:54
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Do you have a unique DN assigned to each ephone, and is the DN a dual-line DN?  If so, a transfer to another IP phone extension should work by default.  If it isn't, chances are you have a shared DN configured between the two phones, or you added it as a single line DN.

Correct Answer
Rob Huffman Wed, 09/08/2010 - 11:56
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Hi Yomi,


Try



ephone-dn  49   dual-line
number 012701062
trunk 49
!
!
ephone-dn  50   dual-line
number 012701061
trunk 50


Cheers!

Rob

Rob Huffman Wed, 09/08/2010 - 12:07
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Nice one Steve I didn't mean to duplicate your good answer

.......my horrid typing skills let me down once again! +5 my friend.


Cheers!

Rob

Correct Answer
Steven Holl Wed, 09/08/2010 - 12:18
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  • Cisco Employee,

No worries.  Also we should note that if you have FXO trunks on CME, transfer isn't supported:


PSTN FXO Trunk Lines
...
Calls placed to or received on an FXO line have restricted Cisco Unified CME services and cannot be transferred by Cisco Unified CME. However, phone users are able to access hookflash-controlled PSTN services using the Flash soft key.


I'd recommend you use the IP PBX mode instead of trunking phone's DNs directly to the FXO port.  It's more flexible.  You can use line monitoring or phone watching to have users know if everyone is on the phone.

Abayomi Smith Wed, 09/08/2010 - 13:02
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Hi Steve & Rob,

Thanks a lot guys, you guys have been extremely helpful and everything is all sorted now. All thanks to you


Best Regards,

Yomi

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