Having problems connecting my works Voip phone, I have power and internet running to the phone and can make internal work call, I recieve calls however when I make an outgoing call the other person can not hear me.
I'm no expert but was researching this for myself recently (and you've had no other answers yet :-))...
It seems that many consumer routers and Home Hubs specifically implement things which can cause VOIP issues. Unfortunately they also don't offer the lower level settings needed to change thngs to get VOIP working.
I think you may be limited to trying STUN vs non-STUN
FWIW, I have recently signed up to voipfone whils I was with Sky. I had some problems where calls stayed conneted after hanging up and at one point had one way audio only, buyt then somehow got it working. I can't give details as I've just switched to BT Infinity with a HH6/Smart Hub and touch wood, a standard install of the soft VOIP phone (Zoiper) and configuration appears to work OK (basic testing not extended use).