hamish225: Oh i didn't realise you couldn't just log into the same voip account on several phones...
Well using the gigaset ones the phones themselves just use DECT to talk to the base station. The base station is the thing that makes the SIP registration and it only makes one (or a max of 6). They have a half decent Web GUI that allows you to set up and the registrations. You can say for incoming calls on 'SIP provider 1' ring all the phones. Or if you had multiple registrations you can see for incoming calls on on 'SIP 1' ring phones 3,4,6. And for incoming calls on 'SIP 2' ring phones 1,2,5. And then you can say for all outgoing calls use 'SIP 1'. Very flexible and quite cheap.
Here is the base with one handset:
https://nicegear.co.nz/cordless/siemens-gigaset-a510ip/
and here is the extra handsets:
https://nicegear.co.nz/cordless/siemens-gigaset-a510h/
They also have this really gimmicky info service. Kind of stupid but quite a cool little exra thing. It can display the weather, news, etc on the handset when in standby.
Also you get a free 'gigaset.com' VoIP line. Allows for free calls with other people who have gigaset IP phones. Haven't used it yet so not sure how good it is.
Gosh I think I should go work for Siemens. Sound like a bloody salesman after that spiel lol.