Problems with 3 way calling

get tried 3 way callign in this, it works, but the voice is kind of choppy and the 3rd party has problems hearing , what could be done to fix this, i really need this working

With so little information to go on, all I can guess is that you are maxing out your bandwidth.

i am getting like 512 download and 128up, and i am using a linksys adaptor for conferencing, how much bandwidth do i need for a call. i tried with G711 and g729 both.