I could use help networking a USB + Serial MTP AV with DP3

[part12studios]

Hi everyone,

This is a kind fo two parter question:

1.

I recently got myself a G4 sawtooth going running OS9 and Digital Performer 3. I have a MIDI Express XT that works well and a MTP AV USB that works as well.

However I also own two MTP AV (serial) units (bought a 2nd one thinking the networking was independent of a computer, my mistake)

I know for a fact that it's documented that a serial MTP AV can work with a USB one to effectively become 16 MIDI In / out.

I bought the serial cable (round) needed to plug into the two net ports on MTP USB and Serial

I followed the instructions to set the two.. the USB AV is set to 1-8.. the serial is set to 9-16.. set to MTP.. set to fastest transfer. both are on unique numbers.. 18 and 22 (tried various numbers, this is just what i'm on right now)

The USB MTP is running 2.1.0 roms.. the serial is running 1.2.0. Maybe that's the issue? I'm not sure if the 2.1.0 roms would be needed on the serial versions.. or if those 2.1.0 roms would even work on the serial version.

Any thoughts? Should if networked correctly they both show up visually connected via free MIDI configuration view?


2.

I'm using Freemidi for the configuration and i'm a little confused about how to use it too because it seem like even when the MIDI expres XT was off / not plugged in it still shows up in my setup and i can't remove it. when i try it tells me to go to freemidi preferences but there is nothing in those simple menu options that appear to offer anything i see as related to allowing devices to be removed / edited.

I feel like it seems that me opening "free MIDI 1.4.9" is the program.. not a profile i can delete and start over.. just generally confused about how free MIDI is treating machines.. i would think that when the MIDI express xt is off / removed it would disappear when i do a "scan" of the system.

Any insight / thoughts on this would be super helpful!

Thanks!
Caleb

[mikehalloran]

There is no 2.1.0 ROM. The latest version was 2.0.1 for the USB. I don't know the last version for the serial/parallel version but that is probably not your problem.

Here's the first thing I'd check: There are two different round 8 pin serial cables for the Mac. The modem cable is wired differently than the printer cable. Unless there is a sticker or printing on the cable, I know of no way to tell the difference without getting a continuity tester or Ohm meter and seeing what lights up or goes to zero. You'll find the pin out diagrams online. I believe you need a printer cable and that the modem cable won't work—I'm going from memory and could be wrong.

How fresh are the keep alive batteries? All versions take a CR2032.

The USB manual is online. The Mac version tells you how to do this.

[part12studios]

@mikehalloran that's awesome thanks and great insight.. ok a few things to reply too.

yes correction 2.0.1 it's what my USB unit shows when booting. and yes the serial ones are both 1.2.0 for sure, but good to know that shouldn't be an issue.

here is the cable i ordered on ebay. they are the round serial types but maybe not the exact/correct one.

http://www.ebay.com/itm/141954689232?_t ... EBIDX%3AIT

the confusing thing there is they all clearly say "RS422" under the two serial ports but my googling has come up with no "RS422 cable" that is round like this. they look more like your serial 9 pin looking atari 2600 joystick type.

if this cable above appears to be the wrong one, could you point me to a cable for sale that would be the correct kind? someone in australia is offering to sell an original black cable but they want like $90.. ugh.. hopefully i don't have to go to that extent to get it to work

http://www.ebay.com/itm/Motu-MTP-Serial ... SwVllXHizm

you may be on to something though.. maybe i ordered the wrong kind..

maybe i could rig some kind of serial cable correctly.. anyone know where i could find a schematic to know the right pins? why would apple make two cables distinctly different but share the same port shape?

[magicd]

Here you go:

http://connector.pinouts.ru/8_pin_mini-DIN_male/

Dave