On Thu, 16 Nov 2000
revtor@... wrote:
> I don't want to post this to AH because it is waay of topic so if
> anyone here could give me some answers reply off list thanks. Could I
> build a MIDI thru box with one in and 3 or 4 thrus by just wiring the
> pins of the jacks together? I have no clue, but need a thru.
This would not work as you would ultimately be trying to drive several
LEDs in parallel in the MIDI optos on the remote devices. (The LED with
the lowest forward voltage would 'win' and hog all the current). It is
easy enough, however, the receive the incoming signal through an opto,
then parallel-buffer it for any number of outputs. The old MIDI hardware
spec shows the use of Schmitt-input buffers (e.g., 74LS14) for the OUT and
THRU portions of the circuit. One 74LS14 would be sufficient to buffer
three outputs. I'll draw a circuit later today.
Crow
/∗∗/