I have a remote Ios Gateway with Ios version 12.3(8)T and Pvdm2,conferencing worked correctly for 3 months.
After reboot of Publisher CallManager unfortunately Ios Gateway conferencing doesn't work.
I didn't change configuration in Ios Gateway and Callmanager.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/vvfax_c/callc_c/ccm_c/intcnf2.htm
This document of Conferencing and transconding explain me how correctly configure Ios Gateway.
I found only difference : my Ios Gateway have version 12.3(8)T but Pvdm2 is supported only with 12.3(11)T.
In past i replaced Ios version 12.3(11)T with 12.3(8)T to solve "Dsp not found"problem (Cisco Tac).
Please,could i replace Ios version 12.3(8)T with 12.3(14)T??
Many thanks and sorry for my bad english.