Facit 4070 to PC interface

[tony duell]

> Has anyone ever worked up a PC parallel port to Facit 4070 paper tape
> punch interface?

Are you talking about a modern USB-parallel cable type interface or the
original PC parallel interface where you could individually control all
the lines?

> I found one on a Swedish website. The punch parallel input looks like
> it is TTL compatible, but I can't find anything in the documentation
> that describes the input voltage specifications.

There are at least 3 versions of the 4070 main board. The earliest (and in
my experience most common) one uses DTL running at 6V. Later ones are
TTL. However in all cases I've had no problems directly connected TTL signals
to the 4070. No idea what modern 'TTL compatible' (but not real TTL) would
do.

-tony