I would guess that it's a decision by the mfg of the HU... but on a telematic (?) display screen, it should be only a software limitation, not a h/w one, unless the receiving unit had the limitation built into it. Then the display can only show what the receiver gets.
Looking at your link for the Prius add-on kit, and the screencaps there, I'm a little puzzled as to why it's truncated so much on your unit, as well.
I have one of the original Sony XM-01 transportable units (gee, you can tell *I'm* an early adopter, huh ?
), and it differs in the amount of chars shown than on the built-in unit in my AH.
In addition, there's a display in the upper dash on my AH, to go along with the display on the radio 'proper' (along with the CC set temp, and the clock, it displays the artist / title when the songs change or commercials / info messages play- but not on *all* stations!), and the # of chars shown differs between the two of *them* (although IIRC, the display scrolls through on the upper section, when it has a phrase that's too big to fit on one screen - I have to verify this, though - usually, my eyes are on the road
)
So your dad owns an RL, huh ? One of the new ones ? How does he (and you) like it ? (I compared the AH to the TL when I was shopping, and saw the RL then) Nice car - but I'm not in the $50K car market at this point in my life. Props to your dad, though...