E1 no voice on Cisco Call Manager version 6

[fgasimzade]

Hello,

We are running Cisco Call Manager with MGCP and E1 connection to a Siemens PSTN

We have started experiencing no voice when calling to Siemens or calling from Siemens to Cisco. The call goes through but there is no ring tone and no voice when the call is answered.

Also, I noticed that MGCP fails back to our Sub sometime, but I am not sure if these issues are somehow related

How can I troubleshoot voice problems with E1?

Thank you

[Mohammed Khan]

Hi fgasimzade,

Can you check with Siemen what channel order do they follow.

Cisco VG follows descending order for outbound calls and expect ascending for incoming calls.

You can toggle config using below commands

interface SerialX/Y/Z:15
isdn bchan-number-order {ascending | descending}.

HTH,

Regards,

Mohammed Noor

[fgasimzade]

Thank you Mohammed

Can the channel order be the reason if voice problems happens from time to time, not always?
 

[Mohammed Khan]

That's Right

[fgasimzade]

Ok, but I think that since we are running MGCP, I would need to do this on the Call Manager side, at the gateway configuration page, right?

[Mohammed Khan]

Hi fgasimzade,

This need to be configured on Voice Gateway.

Regards,

Mohammed Noor