Re: MIDI spec question

H wrote:

> I see that many people ground PIN 2 on MIDI OUT and I'm wondering why --
> pins 4 & 5 on MIDI out drive the opto-isolator on the MIDI INput side
> (pins 5 & 4 respectively).

The standard is that the cable should have
the shield connected to pin 2 at both ends.
In all equipment pin 2 is grounded at the
midi out sockets, including midi through,
but pin 2 at the in socket is not connected.
This puts a grounded shield over the
optoisolated current loop in the cable but
does not connect equipment electrically.

--
Ian Stirling, G4ICV, AB2GR, Long Valley, New Jersey, USA.
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