What hardware? What router model and what modules and DSPs. What do you want to do? Is this for a single site? Or do you have remote sites you want to do hardware conferencing for (so the conference streams don't come over the WAN.)
See http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008037e2da.html#wp1036250
Per 2801/2811 (2 PVDM2-64)
â¢G.711 only conference-50 sessions
â¢G.729, G.729a, G.729ab, G.729b conference-16 sessions
â¢GSM FR conference-7 sessions
â¢GSM EFR conference-5 sessions
â¢Transcoding for G.711 to G.729a/G.729ab/GSMFR-64 sessions
â¢Transcoding for G.711 to G.729/G.729b/GSM EFR-48 sessions