Plantronics + Polycom.
Now together as
if i tried to make a VC calls from public IP it get connect but as same if somebody try to make incoming calls first time it shows (call is ended).
If once again try it on same IP it shows (Far site is busy call again later).
I tried from LAN and WAN link it was showing same issue. Polycom m100 is a software based VC I tried from our laptop to VC still it was showing the same (Far site is busy call again later).
We arrange a Dlink eight port switch from which we made our own network with point to point that is VC and Laptop from VC it was connecting but from laptop same message.
I arrange with standby system of Cisco C20 and made calls to test sites and other sites it was getting connecting but if we try to make incoming calls from other sites it show the same problem.
Then I tried with C20 and Laptop with created own network it was connecting through VC but not from Laptop.