Posts made by IT-ADMIN

Hi guys, i'm new in this forum
i have a question about VOIP,
let's have a look in my current situation, i have 2 location : main office and branch office connected together with site to site VPN, in the main office i have small network 25 computers (soft phones) and one IP PBX,
in the branch office i have 8 computers (soft phones)
the IP PBX in the main office is connected via ISDN connectivity (E1 10 channel)
the computers in the branch were registered successfully in the IP PBX (which is located in the main)
when i call an extension from the main to the branch or from the branch to the main i can hear the dial tone and the call is established but the problem is after the call was established i cannot hear anything in both sides and after a short time the call end automatically
IP PBX : Ozeki Phone System XE
VPN server : pfsense