[GreenKeys] Interface board for Model 15 with 60mA current loop

[Jim Haynes]

Apropos of all this, I have a much more complicated circuit, similarly
untested yet, for what I call a leg combiner.  This allows you to put the
keyboard and printer in series into a single loop, and develops separate
quasi-RS-232 send and receive legs.  The cool thing is that you can tie
the receive data and send data legs together and it won't lock up when
you send a space.

This is a very hasty description, but the basic idea is that a number of
send and receive legs can be hooked together in a parallel "hub", so that
any sender can drive all the receivers and any sender going spacing sends
spacing to the hub.

I don't have a web site to put this on, but I can mail out copies of
the schematic to those who ask for it.



jhhaynes at earthlink dot net