Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!oliveb!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga
Subject: Re: MIDI Problems on A1000
Summary: No power probably.
Message-ID: <103747@sun.Eng.Sun.COM>
Date: 9 May 89 00:29:32 GMT
References: <12517@shamash.cdc.com>
Sender: news@sun.Eng.Sun.COM
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Followup-To: comp.sys.amiga
Organization: Sun Microsystems, Mountain View
Lines: 65

In article <12517@shamash.cdc.com> jwabik@shamash.cdc.com (Jeff Wabik) writes:
>Hi ..  I'm having some problems getting MIDI gear running with my A1000..  
>Here's the scoop.  

Great, but in the future don't post the question to *both* comp.sys.amiga
and comp.sys.amiga.tech. In this case, the question is about using a 
peripheral with your Amiga, an excellent question for comp.sys.amiga, if
it asked how to build a MIDI interface it would be .tech material. See
the difference? 

>I am using a standard null-modem cable for the serial attachment of the 
>A1000 to the MIDI Interface.

This is your first problem. The MIDI interface is expecting you to connect
a straight through connector from the Amiga to the MIDI interface. Not only
that but it wants all 25 pins so that it can draw power from your A1000.

The interface is an _active_ device that needs the power so 7 wire cables
are definitely out. Use the that cable on the serial connector of the ECS
box that you connect to your modem or whatever.

>My cabing goes from MIDI-OUT on the Casio to MIDI-IN on the Interface,
>and MIDI-IN on the Casio to MIDI-OUT on the Interface.  Serial out on
>the A1000 to Serial in on the Interface.    Serial out of the Interface
>to my modem.

These are the correct connections. (With the caveat that the cable between
the Amiga and interface should have 25 pins)


>In trying to be cost effective about this, I decided to build my own
>cables.  Near as I can tell MIDI uses only three of the 5 assigned pins.
>In this configuration:
>
>
>		 3
>	      2     4             <-- Use your imagination and picture
>	     1       5                these in a semi-circle.
>
>Pin 3 seems to be the ground, pin 2 is +5V, and pin 4 is the signal.
>On the knowledgeable advice of several in comp.sys.amiga, I wired
>pin 1 to 1, 2 to 2, ... 5 to 5. 

Well, even if you are being cost effective you really should stop by
the library sometime. Look for a book called "MIDI for Musicians" 
which has not only a good description of MIDI but schematics for a
simple interface as well. Your guesses on the cable are incorrect.
Pins 2 and 4 are a "current loop" interface, Pin 3 is the ground
and should only be connected at one end (to prevent ground loops)
[All this is explained in the book].

>If there's anyone out there who's had experience dealing with MIDI,
>this type of Casio keyboard, or Deluxe Music Construction Set, please
>get back to me, either by posting here, or via e/mail.  There's
>a digital musician in me just dying to get out.

Get either a 25pin straight cable or make one with 25 conductor ribbon
cable and two 25pin insulation displacement connectors. 

Everything will then work as advertised.

--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.
"A most excellent barbarian ... Genghis Kahn!"