Ive just bought one, and after 2 days trying, still cannot get any audio from a Sipgate trunk. :twisted:
Trunks and extensions register fine, calls connect fine, just no audio to/from extensions,voicemail or autoattendant.
Registering handsets directly with Sipgate there are no problems.
I'm using WAN 4 if that makes any difference.

Anyone else had similar issues?

An update for all:
I have spend some time with Draytek support and done some of my own tests.
The PBX audio etc works fine when used with both WAN 1 (VDSL line ) and WAN 2 (via Bt openread modem). So no issues there (so far).
There is still no audio when using WAN3 or WAN4 via a USB 3G/4G modem from the supported list.
I have tried 2 different types of supported modems, 3G using PPP connection and 4G using DHCP connection.
I have a SIPGATE and a DRAYTEL SIP trunk registered but no audio on either. I also have set up a directly registered trunk from the handset to SIPGATE (this works fine with a STUN server enabled on the handset).
Tried the following options and combinations thereof:
ALG enabled and disabled (using Telnet commands).
Router STUN server enabled and disabled.
Opened all the relevant Voip ports.
Disabled the firewall.
Internet access etc is fine.
Can't use Wireshark to trace the problem as the router will not allow mirroing WAN3 or WAN 4 to a LAN port.

I've really spent a lot of time on this, but I'm not an expert in this field. I am pretty confident it's a software issue rather than a NAT issue. I believe the NAT works the same whichever WAN port I use?? (anyone?).
I would be grateful if anyone has any other suggestions or work arounds. My business runs on 3G/4G connection as VDSL is not available here. In the usual Openreach customer service, the FTTC box is at the end of the road and working. I have a cable and JB already in the unit, with a phone line that was previously working. They just can't be bothered to patch across the 30 or so businesses on the estate to the cabinet. If I can get this working over 4G I shall never rent a BT landline again. The neighbouring businesses are eagerly waiting for me to get this working before they consider buying one as they are in the same boat with their ADSL speeds.

any help appreciated.

Is it possible it's your 3G provider blocking VoIP/data ?

How about installing some SIP software on your phone and connecting itdirectly to SIPgate via the router's WAN3 but NOT using the router's SIP/PBX.

The BX2000's SIP ALG functionality is for clients, the PBX's SIP server/client facility can't / doesn't use this.

The BX2000 is a pretty new product and NAT and CG-NAT are becoming more common these days so I think asking for STUN functionality for the PBX system's SIP trunks would be the best way to resolve this. Perhaps ask DrayTek support if that can be added?

I have been working with tech support trying to resolve this issue and in all honesty, they have been trying to get things working. But alas, no resolution yet.
The support tech (thank you if you read this) has internally requested a STUN feature for the IPBX. I don't know how long this will take, there has been another software release since starting on this problem, but still no STUN feature. There is a STUN setting in the router but this is not related to the IPBX portion of the device.

If anyone could check status internally at Draytek I would be very grateful. From my experience most VOIP devices I have used have a STUN feature to get around various problems, so it seems pretty much essential. I wonder why it was not included on a advanced product like this.

EDIT:
by the way the carrier does not block VOIP as I've been using it for years now by registering the handset direct to the VOIP provider server using the internal STUN, bypassing the IPPBX. I bought the BX2000 to upgrade a 2830n and have a basic office pbx with voicemail, internal transfer etc etc. But... lots of money spent... no pbx :x . or RADIUS server as i was led to believe. These 2 items would make it a killer router for SMB !

UPDATE:

I thought i would post this to be fair to Draytek. New firmware 3.8.1.4 now seems to resolve SIP trunk audio over 4G! Whey hey at last my brick has become useful again.

Well, almost....
It will only work for about 15 minute period though, and the trunk seems to lose registration again. I'll keep you posted.

Please Draytek, help me!