[RTTY] What causes RTTY with longish character spacing?

[Jim Reisert AD1C]

Every now and then during a RTTY contest, I hear a station that sounds
like they are typing the characters as they go, such that the letters
get printed more slowly than if they had been sent out automatically
(in one "burst").  But the spacing between the letters is too regular
for it to be just someone typing in real-time.

Assuming no one is still using old (pre-computer) hardware, what
accounts for this?

73 - Jim AD1C

-- 
Jim Reisert AD1C, <jjreisert at alum.mit.edu>, http://www.ad1c.us