Careful wording

"Session Initiation Protocol (SIP), used for Voice over IP telephony."

Not quite

VoIP can use SIP, but equally h323 and several others.

SIP is also used (and was orginally designed for), webcasts, IM and many other things.

Also just because 2 devices use SIP, doesn't mean they can talk to each other, as their real time codecs can be completly incompatible.

So not on do you need an open connection (such as SIP) you ideally need an open codec as well.

No here is the crunch, every SIP phone can (should) support g711, but you'll find only some support g729, a licensed codec, the same could happen with Cisco.

To be honest, our systems support about 50 codecs, but we stick with G711, just so it's bloody easier (and sounds better)

1 meg... hope their codecs are up to it

You seem to get a CIF image at reasonable compression and slightly tinny audio for 768kbit duplex, so far as I've seen. 1mbit broadband will probably be no more than 256k upstream, so that better have some much-improved compression going on to bring resolution up a bit (so domestic customers don't complain about how blurry/blocky it is) whilst still giving a good framerate and lack of smooshyness with one-third of the bit budget.

But good on 'em anyway. It's about time we made it to the Star Trek future, where everyone has a subspace comms viewscreen in their house.