The asterisk server can talk to a wide variety of devices, out of which we use only a few.
snom320/360 VoIP Telephones
I bought 60 phones in Jan 2007, which should suffice for some time. The remaining ones are stored in the cupboards in the Archive (room 013). The MAC address is their distinguishing property, which is conveniently printed (including a barcode version) on the box. The only difference between these phones and analog ones is that you should dial before picking up the receiver, otherwise you need to end the dialing with the check-mark button.
One thing to remember: after installation, remove the small black rubber strip from the receiver cradle, otherwise you'll get plenty of user complaints about a non-working phone.
Softphones
There is no reason why the snom telephone's functionality should not be implementable on a normal computer, and indeed, there is a plethora of so-called softphones. Since I'm on Mac, I've only tested them there.
zoiper Formerly Idefisk, which name I liked better. However, the sound quality is poor and the handling needs some getting used to X-Lite The best I've seen so far, but sometimes it gets confused when (un-)plugging headphones, resulting in no sound until cured from the settings menu
I have not tried commercial versions.
Softphone Registration
As usual, talk to Gebert, telling him your office number, and he will add an additional device in the asterisk server. In contrast to the snom phones, this time he will give you the account name and password, so that the softphone can authenticate itself to the server. In addition to the username and password you will have to specify an authorization name and a domain in the Softphone setup. The authorization name is the same as your username, and the domain is voip.lrz.de.