[sdiy] Wire selection question

[media.nai at rcn.com]

At 9:49 AM -0500 03/15/02, Dave Magnuson wrote:
>
>I have some twisted-pair wire here, and I was wondering if you think it
>would be acceptable for the MIDI connections.  The cable will be about 25
>feet long and run in the stud cavities.  My cable is (4) twisted pairs with
>a 100% foil shield and a drain.  The conductors are single strand... about
>20 or 22ga.
>
>Since it'll be in a wall, I'm not concerned about the single strand wires
>breaking.  Electrically do you think it will work well for a MIDI
>application?  It's twisted-pair computer network cable, so I'm thinking
>it'll be okay.

I'm thinking it could work, but it would not be within the MIDI spec.
Contrary to popular belief, MIDI specifies three conductors using a
shielded two conductor twisted pair, a signal on pin 5, a +5V bias voltage
on pin 4, and pin 2 grounded to the shield on one end.  Each twisted pair
should have its own separate shield.  Using a common shield for several
pairs could cause problems.