We have 3 Polycom VSX 7000a devices in 3 seperate locations. Our locations are connected via Bellsouth's Metro E lines (100mbps). One Polycom device has the ability to call two devices for a 3 way video conference. Recently when we call the the two devices we can not see or hear them but they can see and hear us. I've been checking all 3 devices and i dont see anything that has changed (as far as i can tell).I'm guessing its a port issue (although we don't have a firewall inbetween the offices, only out to the internet). But i find it strange they can see and hear us fine but we can see or hear them.