Hi Charles,
DSP resources (DSPFarm) can come into play when transferring calls (example from g.711 to g.729) Have a look;
Transcoding Support Overview
Versions of Cisco Unified CME earlier than Cisco CME 3.2 supported G.729 compressed voice calls for two-party calls only. Cisco CME 3.2 and later versions support transcoding between G.711 and G.729 for the following features:
Ad hoc conferencing One or more remote conferencing parties uses G.729.
Call transfer and forward One leg of a Voice over IP (VoIP)-to-VoIP hairpin call uses G.711 and the other leg uses G.729. A hairpin call is an incoming call that is transferred or forwarded over the same interface from which it arrived.
From this doc;
http://www.cisco.com/en/US/products/sw/voicesw/ps4625/products_configuration_guide_chapter09186a00806a8015.html
Hope this helps! Happy Holidays!
Rob
