[cisco-voip] Where is ring back generated?

[Robert Kulagowski]

As part of my continuing effort to mess around with stuff, I've got a 
Tandberg 3241 PRI gateway terminating PRIs from MaBell.  It has a H.323 
connection to a 2851.  Inbound callers don't hear ringback, but there is 
an audio path once the called person goes off-hook.

Can someone who's deeper into H.323 let me know where the ringback is 
supposed to be coming from?  Should the Codian generate ringback 
immediately, or is it waiting for a H.323 message from the Cisco, or is 
this just in the "too hard to do" category?