A lot of
people don't like key clicks.  I do.  When I worked at IBM I
 received a lot of dirty looks for typing on a 3279 terminal, in an open 
 Not half as bad as the looks _I_ got for using a Flexowriter to punch a
 tape in a public terminal room at Cambridge University about 10 years ago
 (everybody else was using _silent_ video terminals, mostly BBC micros). 
 Was I
there?  I don't recall the incident.
   plan office,
without turning off the key clicker.  Now that really was
 loud! 
 I have a keyboard somewhere with a little solenoid in it that hits the
 metal baseplate for a keyclick. Now that is loud! 
 
3278 and 3279 were similar, except that it wasn't the metal base plate.  I
never dismantled one, but it sounded like one of those plastic resonators
you get in some toy guns.
Philip.