The answer is: It depends! ;)
I've done this before, and recreated it quickly to post the following:
When receiving a call and the name display has 14 or fewer characters, it will show:
From
(DN)
When receiving a call and the name display has 15 or more characters, it will show:
From <13 chars>...
(DN)
When placing a call to a DN and the name display has 17 or less characters, the display will show:
To
(DN)
When placing a call to a DN and the name display has 18 or more characters, the display will show:
To <16char>...
(DN)
Some notes:
-you can have up to 30 characters in the Display (Internal Caller ID) field
-all characters will show up in the directories listing (up to 30 anyways that I tested)
-some of the lines on the display use proportional font, some use non-proportional, so it can be misleading, e.g. the line text I believe uses proportional so it's hard to line up text on the phone.
