Which providers allow SIP (VoIP) calls over their networks?
Planning on changing phone and contract soon and since my 'landline' and home office line are both SIP it would be nice to be able to pick up calls on my mobile when out and about (e.g. with Gingerbread's built in SIP client).
However often buried in the network's T&Cs there's a 'no internet calls' clause. Anyone know which (if any) UK networks do allow it and do those that say you can't actually block it (e.g. port-blocking) or just complain if you use it too much (the handset itself will be unlocked/unbranded so not blocked at that level)?
I wouldn't be looking at using it excessively (I really only want to prevent missing inbound calls) and wouldn't be on an 'all you can eat' data plan anyway.
I know it'll work over WiFi but would be much nicer if it worked over the cellular network too.