FWD one way audio SPA3102

[TheFug]

I hope somebody can put me in the right direction:
Have IPkall hooked onto my FWD account, all works perfect when i receive calls on a softphone on my laptop, but when received on my SPA3102, connected onto my router, phone, and landline, i hear only sound in the called phone, where and how should i edit in settings, so i have both ways audio ?
or link me to where i can find a detailed solution, TIA !

[TheFug]

Problem solved by replacing modem/router which does correctly handle the NAT for VoIP.