From: ttl@aura.cs.wisc.edu (Tony Laundrie) Subject: Re: Radio Shack Secret? (Midi cables) Date: 8 Aug 91 17:38:55 GMT > (From Bob McQueer's MIDI Spec Primer) > > The standard connectors used for MIDI are 5 pin DIN. Separate sockets > are used for input and output, clearly marked on a given device. The > spec. gives 50 feet as the maximum cable length. Cables are to be > shielded twisted pair, with the shield connecting pin 2 at both ends. > The pair is pins 4 and 5, pins 1 and 3 being unconnected: > > 2 > 5 4 > 3 1 If you buy a generic cable, it probably looks like: /\ ################# /\ 1 -|------#################---|------ 1 | | ################# | | 2 -|------#################---|------ 2 | | ################# | | 3 -|------#################---|------ 3 | | ################# | | 4 -|------#################---|------ 4 | | ################# | | 5 -|------#################---|----- 5 | | ################# | | \/ ################# \/ \___/ SHIELD \___/ Metal Shell of DIN Connector This probably works, but it might be electrically noisy, and perhaps not reliable for long distances. If you make your own cables with 2-conductor shielded wire as described in the SPEC, do it as shown below: /\ /\ /\ / ################# \ /\ 1 -|- | | ################# | | ----- 1 | | | ################# | | | 2 -|-----/ ################# \--|------ 2 | | ################# | | 3 -|- | ################# | ----- 3 | | ################# | | 4 -|----------#################-------|------ 4 | | ################# | | 5 -|----------#################-------|----- 5 | | ################# | | \/ ################# \/ \_ SHIELD _/ Metal shell of DIN Connector Connect the wire shield to pin 2, and connect pins 4 and 5 with the other wires. Do NOT connect the metal shell of the DIN connector to the wire shield (pin 2) -- I had pin 2 shorted with the shell at first and that didn't work with my setup. ttl@cs.wisc.edu From: janin@v785.stanley.co.jp (chan" Janin) Subject: Re: MIDI DIN connector pin-out needed Date: 7 Jan 92 10:18:06 GMT ************************************************************************ * Please Please, Refrain from "Email"-ing me... Look at my Signature ! * ************************************************************************ In article <311@ittc.wec.com> simmons@ittc.wec.com (Gary Simmons) writes: >A friend got a Soundblaster for Xmas and wants to make his own cable >to go between the 15 pin connector on the SB card to a MIDI connector >on the other. What pins do what on the MIDI end? I remember a bit of >discussion on this a while back, but didn't save any of it... > >Thanks, > >Garry Simmons >simmons@ittc.wec.com I hope nodoby replied you before me... This is the TRUE pin assignment for MIDI plugs. I know it "by heart" because I used to make my own interfaces for my computers... MIDI IN : 1- n.c. 4- anode of optocoupler 2- n.c. <<<--- !!!! Different for MIDI OUT 5- cathode of optocoupler 3- n.c. MIDI OUT/THRU: 1- n.c. 4- +5v thru resistor 2- local ground 5- TTL open collector ouput 3- n.c. The pin numbers are usually printed into the plastic of the plug, in that order (or the reversed one). Don't connect MIDI IN pin 2... it preserves OPTOISOLATION from MIDI OUT device to MIDI IN device. To make your own MIDI cable, wire pin 4 to 4, pin 5 to 5, pin 2 to 2 and to the shield of your cable. ------------------------------------------------------------------------ Pascal JANIN -Amiga & Anime Addict Forever | "Buki! Buki!" Pi-chan says < STANLEY ELECTRIC CO. LTD, R&D LAB 71G > | // My 1st computer: DAI < Fax: 81+ 45-9110007 (045-... from Japan> | \ // My current 2nd:Amiga *** I can r/w E-mail ONLY inside Japan *** | \X/ ...ONLY the bests !! *** Sorry, you'd fax or use "F" option *** | Discard all Pee-Cee users ! ------------------------------------------------------------------------ From: smill@polari.online.com Subject: Re: Now what? (MIDI) As stated in the MIDI 1.0 Spec: "The cable shall be twisted pair, with the shield connected to pin 2 at both ends." ^^^^^^^^^^^^ The ground loop problem is dealt with in the fact that MIDI jacks on instruments are specified as pin 2 (ground) being connected only at the transmitting ends, not at receiving end. This allows cables to be used in any situation, with the ground connection taken care of in the hardware specification. -- Steven M. Miller "The history of music evolution is smill@polari.online.com not the history of nice guys" -- Anthony Braxton Electronic Music Coordinator - Cornish College of the Arts, Seattle WA