how much bandwidth I need for one voice channel

[admin_2]

I got two PVC from a host router ( access link is 56 K) going to 2 remote locations, each PVC is 16 K CIR.

How much bandwidth I need for each voice channel to be initiated from host location.

[#2]

you need to use g729 and with VAD, header compression enabled.

one call will consume about 11-12k.

[fbahram]

This depends, do you have VOFR or VOIP? If VOIP, then as other response says, 11-12k with vad and cRTP. VOFR is 10k/call for g729 and there is no cRTP for VOFR, vad can help to some extent. So for 56k, you can run up to 5 calls comfortably if you do traffic-shapign and prioritization correctly.

Hope this helps.