asterisk users - May 2007 - a/b door phone

Hi!

I would like to connect a door phone to my asterisk server.
I decided to do that with an analog (a/b) doorphone and a sipura box.

Can anyone give me a recommendation for a door phone with good voice
quality?

I am from Austria/Europe and I looked at products from Rocom and from
Auerswald.

Does anyone use one of these door phones and can me tell his/her opinion
on that?!

thx in advance,
tom