I've just bought a Sipura SPA 3000 after having a play around with XLite and being quite happy with VoIP (using 1899.com).
However, when I make a call over VoIP, the person I'm calling can hear me, but I can't hear them.
From looking around the web, it sounds like this is a common problem when a hardware VoIP device is behind an NAT (as mine is). However, I haven't really found a solution in works of one syllable! (I really am very new at this whole VoIP thing).
My internet connection is via a cable modem (2Mb down, 512Kb up), and the cable modem is plugged into a Linksys BEFSR41 router. My SPA 3000 is plugged into one of the ports on this router.
I've heard that a STUN server should be able to get around NAT problems, but although I've set a STUN server in the SPA config, I still get the same problem.
My router supports uPnP, which, again, I understand should make things easier! (I also know very little about uPnP I'm afraid!).
I get the same problem with a couple of different SIPs I've tried.
Does anyone have any ideas? Am I correct in thinking it's a NAT problem? Is it worth me putting the SPA in the DMZ and see if that works? Otherwise, do I need to forward any ports to the SPA? (although I thought STUN and/or uPnP got around this problem!).