Digit Stripping on Cisco VG350 FXO Port Instead of CUCM

[conor.maton]

Hello all,

I have a Cisco VG350 which has one of its FXO ports connecting to another PABX which is configured as a hotline (ie. has no digit matching/route pattern in it's config, it just looks for a loop on the line then routes the call).

The intial config had an entry into its Route Paterrn (for the sake of this topic the DN is 1234) which then routes to the specific FXO port. The far end PABX we thought would disregard any digits sent as there is a loop on the line so doesn't care about the digits, but the conclusion was the PABX sent back what sounded like an NU tone and I think it was getting confused by the digits being sent. As the far end system isn't ours we cannot modify that config so we have to change ours to suit.

We then decided to use PreDot trailing on the CUCM RP (i.e. '12345.') so no digits are sent. This worked ringing the far end, however the initiaing 3rd party SIP phone is a trader type touchscreen which needs to know the DN in order to identify what far end phone is being contacted (customer requirement).

Hence my question; could the FXO complete the digit stripping instead? The 3rd party SIP phone has no logial interface to the VG350 during the call initiation so we could change the CUCM RP to '12345', remove the PreDot digit stripping on CUCM and the third party phone would be none the wiser.

The Cisco VG350 communicates to CUCM via MGCP. The port in question is FXO 0/0/1, specific config from the VG350 below (all completed on CUCM and pushed to the VG350):

!
mgcp
mgcp call-agent 10.100.10.2 2427 service-type mgcp version 0.1
mgcp dtmf-relay voip codec all mode out-of-band
mgcp rtp unreachable timeout 1000 action notify
mgcp modem passthrough voip mode nse
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp package-capability pre-package
no mgcp package-capability res-package
no mgcp timer receive-rtcp
mgcp sdp simple
mgcp fax t38 inhibit
mgcp bind control source-interface Loopback0
mgcp bind media source-interface Loopback0
mgcp behavior rsip-range tgcp-only
mgcp behavior comedia-role none
mgcp behavior comedia-check-media-src disable
mgcp behavior comedia-sdp-force disable
!
mgcp profile default
!
ccm-manager music-on-hold
!
ccm-manager redundant-host 10.100.10.3 10.100.10.4
ccm-manager mgcp
no ccm-manager fax protocol cisco
ccm-manager config server 10.100.10.5 10.100.10.1
ccm-manager config

!
voice-port 0/0/1
no battery-reversal
cptone GB
timing hookflash-out 50
impedance complex2
!
dial-peer voice 999001 pots
service mgcpapp
port 0/0/1

!

Thanks in advance!

[Roger Kallberg]

Not sure what additional information I can provide to help you understand this as I already tried to explain it two times. Suggest you reference the documentation available to see if you can find information on this that might make it clearer for you.

[Roger Kallberg]

Have a look at this presentation from Cisco Live by the master of dial plan, Johannes Krohn. https://www.ciscolive.com/c/dam/r/ciscolive/us/docs/2015/pdf/BRKUCC-2008.pdf

It has this part in it that explains the behavior you see.

 Possibly this could be the information you need to understand why it's behaving the way you see.

[Roger Kallberg]

.