Problems with Grandstream ATA-486 & Vigor 2200USB router

Archived from groups: comp.dcom.voice-over-ip (More info?)

I'm trying to set up a Grandstream ATA-486 in conjunction with a Draytek
Vigor 2200USB router. I have the 486 configured as instructed by the voip
service I want to use (Sipgate) and it works fine for incoming calls, but
I can't dial out, even after adding credit to my account.

The instructions say to set the router's DMZ to the IP of the 486 and to
forward ports 5004 & 5060 (UDP) there also. I've done this, but still no
luck.

I tried the 486 at a friend's house in conjunction with his cable modem
and it works fine there, so I don't know what the problem is, but I
suspect the router's setting somewhere. I upgraded the router's firmware
to the latest version in case it was that, but no luck.

Can anyone point me in the right direction..? I have had a one-line reply
from Sipgate telling me to check the configuration of the 486 but they
don't say what *should* be set. Still awaiting a reply from Draytek.

Ivor