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MIDI I/O through ethernet

Discussion in 'Recording' started by kylempetersen, Dec 17, 2008.

  1. Has anyone had their MIDI I/O set up in a rack across the room from their computer (which is in a separate machine room) and use USB out of the back of the interface to a USB/Ethernet converter and then ran the ethernet through the floor/wall to an Ethernet/USB converter and then into their USB port on their computer? If you have...have you had anytime trouble getting your computer to recognize the interface?
     
  2. hueseph

    hueseph Well-Known Member

    That's an awful lot of conversion going on there. Why not just go midi to USB?
     
  3. It's only converting it twice. USB to ethernet and then from ethernet back to USB. I don't know why they just didn't run a really long USB cable through the wall/floor. It's a studio that I've been working at. I guess it was easier to wire? I have no idea. Just curious if anyone has had the problem of their computer not recognizing their interface? Because I did figure out that there was something with the ethernet that just didn't work (I should say doesn't work anymore because it was working at one point). I took the I/O out of the rack and connected to directly to computer via USB and it worked...so it's something to do with the ethernet. Very interesting.
     
  4. Space

    Space Well-Known Member

    It reads like this is more a by-product of the operating system losing connection with the hardware rather than simply forgetting that the hardware was available.
     
  5. Boswell

    Boswell Moderator Distinguished Member

    MIDI is just a serial line protocol, and USB MIDI ports are simply serial line ports implemented at a distance through a USB carrier.

    From my experience of ethernet USB extenders, what you are proposing is going to give you problems of unreliable connectivity.

    You would be much better off using RS422 differential cabling as the long-haul physical medium. RS422 can run over two pair plus shield cabling for several miles, so will be fine for studio infrastructure use, especially at the moderate bit rates that MIDI uses. You would need a USB-RS422 adaptor at the computer end and simple RS422-RS232 level conversion at the MIDI equipment end if your MIDI gear cannot be configured for RS422 I/O.

    RS422 tutorial
    Interface comparison table
     
  6. Boswell,

    Thanks for the information! I've been trying to read up on ethernet connections (some of which I must admit is a bit over my head). And I have read about the unreliable connectivity. I have also read about PoE (Power Over Ethernet). I thought that this might work well considering it would eliminate having to use and AC adaptor for the MIDI interface (if I'm reading and understanding it correctly that is!) Or would this still cause problems because it is still ethernet? Why would I need a RS422-RS232 level conversion at the MIDI interface? Wouldn't I just be able to from USB (out of interface) to USB-RS422 conversion and then RS422-USB at the computer across the room? Like I said, this stuff is a little bit over my head but really would like to learn more about it. Thank you again for the links and the info Boswell.
     
  7. Boswell

    Boswell Moderator Distinguished Member

    From your last post, I'm not sure I understand exactly what you want or that you understood what I was suggesting.

    If you want MIDI capability at a distance, there is no interface involved. You convert from USB to serial line (RS232 for short distances, RS422 for longer) at the computer, and then run the serial line off to where the MIDI gear is located. You connect it to the MIDI IN of the first piece of gear. Whether or not you need a level shifter depends on whether you used RS422 and the gear can handle those levels. Daisy-chain other MIDI gear from this first piece as normal.

    Now what you may be suggesting is that you want to replicate your USB at a distance so that you can plug in a USB-MIDI converter local to the MIDI equipment. If that is the case, I would be wary about using ethernet-based USB extenders, for the reason I gave.

    If you have a USB-MIDI converter and want to continue using it, a compromise would be to locate it next to the computer so it will plug in directly via its USB, and use an RS232 extender kit comprising a pair of RS422 converters with a twin twisted-pair linking them. These are relatively cheap and will regenerate true RS232 levels over a long distance.
     
  8. I may be interchanging "interface" with "I/O" incorrectly. I run out of Pro Tools HD (where all my MIDI information is being written) that is being sent out through a USB port which then converts to an ethernet connection which travels through the wall and then converts back to USB to plug into the Pro Tools MIDI I/O which has several MIDI devices connected into it (thus being able to select which device the information is routed to through Pro Tools). I've found that what seems to be happening is because of the ethernet conversion the Pro Tools MIDI I/O isn't being recognized anymore (it was at one point) by the OS (Mac OS X). So what I am asking (specifically to Boswell) is if that RS422 converters would be a good replacement for the ethernet converters? Would it make the unreliable connection problem disappear? Does that kind of make sense? I'm apologize if I'm not being clear. I really do appreciate your help. Thanks!
     
  9. Boswell

    Boswell Moderator Distinguished Member

    I'm not surprised you are having problems. Ethernet USB extenders are notoriously difficult to get working reliably, and it's not made easier by PT being very picky about recognizing Digi hardware.

    How many pieces of MIDI gear are multiplexed from the MIDI I/O unit? Is it too many to consider locating the I/O unit next to the computer and running individual MIDI cables back through the wall? Do you have to use individual MIDI I/O channels for each MIDI connection or could you daisy-chain some devices (MIDI allows up to 8 chained)?

    Now you have clarified the set-up, the RS422 solution is going to help only where each MIDI cable is too long to operate reliably. It won't reduce the number of MIDI connections needed.
     

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