[cisco-voip] T.38 with VG248's and MGCP PRI Gateways

[Erick B.]

Hi,

Anyone ever do T.38 faxing with VG248s and MGCP PRI gateways?  Have
client that needs to use T38 for a SIP FAX Server they have, but
outbound calls to PSTN from Brother FAX Machines attached to VG248s
are intermittent.  Sometimes they work, sometimes they don't. The
Brother FAX machines have no way to change Baud rate or ECM settings,
etc. They had no problems with passthrough (before the FAX Server was
upgraded to SIP).

Incoming FAX's work fine (a majority - very little issues reported).
Most of these go to FAX server and some go directly to the FAX
machines on the VG248's.

The VG248 ports are set to T.38 peer to peer, and we've tried various
MGCP T38 settings on the gateway with TAC's help but still having
problems with outbound FAXs.

Tried setting gateways to force t38 (mgcp fax t38 gateway force),
tried removing the fxr-package as default (not needed for VG248 per
TAC), and set the ls and hs redundancy settings to 0 (VG248 doesn't
support redundancy), tried with with mgcp fax rate set to 9600 baud,
ECM off on MGCP gateway, etc. Reset MGCP with these changes each time.

Anyone know how to disable VG248 from using Passthrough mode? The port
is set to T.38 peer to peer but when I try changing the Passthrough
setting to "voice only - no passthrough" then no FAXs work at all with
the FAX machine attached to the VG248 port (I bounced the port after
the change also).

Call Manager version is 8.02 with latest 12.4.24T IOS on gateways.


Ideas anyone?

Thanks, Erick