I've found another thread with the same problem but to be honest I just can't understand the discussion ! ( asterix ... pings ..DOH )
We're with italk & using a cisco spa 122 - it's worked just fine since initial teething probs ( where we ended up updating firmware on it ..problem solved )
This is a mystery because it's come from nowhere and we've changed nothing , it just stopped making outgoing calls ( gets a busy signal ).
I have a geeky friend coming to visit in about a week, so can hang in until they get here , however, if there is something 'easy' I can do to fix it in the meantime ...that would be nice.
( I know, I KNOW...I shouldn't even be allowed NEAR a computer or voip set up !!)