T3's are very well made but large phones from German (the folks at Tenovis, last year taken over by Avaya, will be ranting that they sell all over europe but reality in mainly Germany).
They all have large displays which are used for context sensitive menus that change to match what the user is doing and the options available to them - like the 20 Series phones but better.
3 models in order of size small to large - Compact, Classic and Comfort. The Comfort is huge and even includes a mini text character keyboard.
T3 phones actually come in three flavours Upn (similar to DSP), Ipn (ISDN) and IP. The IP Office will be supporting the Upn variants to start with. Don't know if the others will be coming along later.
The special features: hunt groups displays a list of hunt groups and allows the user to change their status and or the groups service status.
personal directory is a list of speed dial numbers and names but it is stored as part of the IP Oifice configuration so moves with the user.