Reccomended Config for Faxes on H323 Gateway and MGCP VG224

[dan hale]

I posted an earlier question on my VG224 having issues with faxes but, never got a reply so I thought I would elaborate more. My current fax flow is below:

Telco – PRI – GW – H323 – CUCM – MGCP – VG224 – Fax/Modem

I'm having intermittent faxes failing. Does anyone have any recommended configuration or what has worked for them that would help faxes succeed.

I'm open to any ideas....passthrough or relay....anything.

The PRI gateway is a 3925 below is what is setup for faxing on the gateway:

fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback none

and on the VG224 is :

mgcp modem passthrough voip mode nse

mgcp fax t38 ls_redundancy 5

mgcp fax t38 hs_redundancy 2

CUCM version 8.6

Thanks for any pointers....Dan

[Harmit Singh]

Hi Dan,

Looking at the current config snips you pasted, the 3925 has protocol based T38 configured, while the VG224 has both T38 and NSE based fax passthrough configured. I would suggest trying the following to see if it helps after removing current fax config (take a backup of it):

For the H323 gateway (3925):

! Fax configuration for Inbound / Outbound VoIP dial-peer !

dial-peer voice 1 voip

  fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback none

  fax-relay ecm disable

  fax nsf 000000

  fax-relay sg3-to-g3

For the MGCP gateway (VG224):

no ccm-manager fax protocol cisco              

no mgcp fax t38 inhibit 

mgcp package-capability fxr-package

mgcp default-package fxr-package

no mgcp fax t38 ecm

mgcp fax t38 nsf 000000

Re-register the Gateway with CallManager by entering the following commands :

no mgcp

mgcp

The above config is for protocol based T38. Let me know how it goes.

HTH.

Regards,

Harmit.