NetTalk VOIP will not work completly

Bare with me, as I am very new to RouterOS (familar with networking and cisco etc)

I have a NetTalk DUO (basically the same principal as a Vonage device. It needs 5060 and 12000 and 12001 open (udp) I have the ATA at 192.168.15.9 with a static IP.

I have tried using a ‘dmz’ with natting dst-nat, ch=dstnat UDP DST 5060 (and 10000-20000) on either all ethernet or the gateway

and opening the firewall on those ports as well…

I get dialtone, and ocasionally I can get rings on both sides, but never and voice either way

What would be the proper way, knowing the ports and IP of the ATA above to do this???

Thx!!!

Scott