Re: DON'T CUT THOSE WIRES !!

> But, I think it is wise not to cut wires, and first try to see if
> the machine can work as it is. TTY is teletype port, and yes, it
> is a current loop, most of the time.
>

If he can find the level shifter chips on that TTY port we could
probably figure out if it is current loop or normal RS232. For
example, if they are 1488's and 1489's, I'm guessing they would not be
current loop but rather normal RS232 signalling. IO ports being
pretty robust, I would think it safe to use the continuity check
function of a modern digital multimeter to determine what chips are
connected to the connector (particularly pins 2 & 3) while the machine
is powered off. Often though it is visually obvious what they drove
the port with.

Chris

--
Christopher C. Stratton, stratton@...
Engineer, Instrument Maker & Horn Player
(978)538-5179 work, (617)492-3358 home
30 Griswold Street Cambridge, MA 02138
http://www.mdc.net/~stratton