| Title: | * * Computer Music, MIDI, and Related Topics * * |
| Notice: | Conference has been write-locked. Use new version. |
| Moderator: | DYPSS1::SCHAFER |
| Created: | Thu Feb 20 1986 |
| Last Modified: | Mon Aug 29 1994 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2852 |
| Total number of notes: | 33157 |
O.k., with all the projects getting cancelled around here in Littleton
I've had time to catch up on notes.
Does anyone know exactly how many of the five lines in a midi
cable are actually used? (Maybe someone with a midi spec out there?)
I've heard that only three of them are actually used; if this is
true, are they the center three pins?
The reason for this is that, to avoid a midi feedback loop,
and also to avoid having to connect and disconnect midi cables,
I'd like to get a simple on/off switch to insert in the midi path.
If the midi cable only uses three of the lines, then I just won't
bother connecting/disconnecting the other two. Does this make sense?
Or, what might be even easier; does anyone know of switches
that already exist to perform this function? I know I could use
a through box that has swtiches and allows turning off certain paths.
Are there other alternatives?
Thanks,
Ron
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1496.1 | I got a millian of 'em (achachachacha) | AKOV75::EATOND | Where d' heck a' we! | Thu Jun 30 1988 12:23 | 18 |
Very simple question. There are indeed only three of the five leads used. 4 and 5 are the only ones you need to be concerned with. 2 is ground and doesn't need to be connected to chassis. I have built a number of simple forking switchers for my network using simple DPDT switches. Just connect leads 4 and 5... It is recommended that you us a switch that allows for center off, though. I just had to trash a switch box I made because it didn't reliably switch from one to the other. Yes, it could be a number of factors (cheap switch, notwithstanding), but I remember reading an article by JL Cooper that recommended the center off configuration. Total cost for a finished switch box using Rat Shack parts - around $7 - not counting the wire and solder. Dan | |||||
| 1496.2 | HEhehehehe | SALEM::AMARTIN | MY AHH..DEEDAHZZ | Fri Jul 01 1988 02:48 | 3 |
Trying to wreck the MD8 already...Huh Ron??? :-)
Glad to see that youre getting some use out of it.
AL
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| 1496.3 | clarification | BEOWLF::BARTH | Fri Jul 01 1988 16:27 | 34 | |
re .1>
Thanks, Dan. Let me see if I got this straight. Of the five
lines, I can disregard numbers 1 and 3. Number 2 can stay connected,
right through the switch. Numbers 4 and 5 can be disconnected with
a simple DPDT switch. Correct?
Aside: Midi data is serial (obviously). So why two lines and
not just one? Just curious.
Further, how do I "decode" which line is which?
^
. .
. .
.
Imagine that to be the end of a midi cable -- the ^ is the notch
on one side, the dots are the five pins. Which is pin 1 and which
is pin 5?
My main application would be to connect one midi cable and
disconnect another with one throw of one switch. For this I imagine
I would need a quad pole, double throw switch. Is there such a
thing?
re .2> To tell you the truth, Al, I don't think I'll be using the
MD8 after all! I just think it's too limiting for live performance
use (doesn't accept pedal hold, program change, etc.) Nice try,
though!
Ron
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| 1496.4 | AKOV88::EATOND | Where d' heck a' we! | Fri Jul 01 1988 17:22 | 19 | |
RE < Note 1496.3 by BEOWLF::BARTH >
From my experience, I just let 2 hang and have found no problems.
Listen to the EE's among us grind their teeth. Ignorance is bliss, I guess.
Since the use of the pins are symetrical, its not crucial that you
distinguish 4 and 5. Here's the layout, basically.
^
. .
1 . . 3
4 . 5
2
Like I said, I only connected 4 and 5, so a DPnT is what you need.
Dan
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