Adding a MIDI Thru

[media at mail1.nai.net]

At 1:22 PM -0400 06/22/98, Andrew Schrock wrote:
>
>Generally speaking I think the longest you can use midi
>cabling before some deterioration is 6 meters. (somebody tell me if i'm
>way off base here)

The MIDI spec states that cables shouldn't be longer than 15 meters.

(well, you asked me to tell you!)

Anyway, as far as I know, to add on a MIDI Thru you tap the signal after
the opto-isolator for the MIDI In (the same signal going to the UART).
This is then buffered (through two inverters in series or an op-amp or
somesuch) and connected to pin 5 with a 220 ohm resistor, pin 4 is
connected to +5V with another 220 ohm resistor, pin 2 is grounded.  As in
all MIDI connections, pins 3 and 1 are unused.

PEACE OUT :)
MARK