MRCC 880 issue with patch data sysex not transmitting from PC to synth DIN input

[WireWrangler]

I downloaded a CZ-101 patch (attached) and sent it the same way as above. Its working as expected, so I don't really know how to troubleshoot the issue. I tried with MIDI OX set both for a 256 byte output buffer, and 266 byte output buffer.



On the MIDI OX input, we can see when set for 256 byte output buffer, the patch sends in 2 parts. With a 266 byte buffer, which is larger than the actual patch size, it sends all in one message of the correct size. Either way, it shouldn't look any different with another MIDI interface, and I have no idea why the synth wouldn't receive it.

By the way, the MRCC 880 doesn't blink the LEDs for SysEx data. I'm thinking about what else we can try... but any bright ideas are welcome :-)

I've just read this page, its complicated to decipher but it indicates that there is two way communication between the CZ and the software. 
http://www.youngmonkey.ca/nose/audio_tec...io-CZ.html

Does the CZ need the output of the synth connected to the input of the computer to complete messages?

Thanks for doing all of that. I really appreciate it.

Don't know how to account for the difference in behavior among MIDI interfaces/routers -- and MIDI OX on Windows and various MIDI apps on macOS -- other than the fact that they are 'different' hardware and software with different OSs and APIs.  This is not a level of programming that I am familiar with - I mean I used to write MIDI apps with high level scripting tools; and low level machine language on a very ancient 6502 processor, but never had to account for SysEx issues with arcane and archaic synthesizers.

Yes, on the MRCC 880, lights don't blink with incoming SysEx, but they do light up... so that's something, at least, to see the routing.

Yes, there is two way communication with the CZ and computer in data dumps.

Yes, I have seen reference to youngmonkey previously as a credit on Patch Base developer's website. Yes, this is some convoluted *&%^ re: CZ's sysex. Somehow, Patch Base's developer deciphered all of that to make a great patch editor - kudos.

And yes, I think the CZ needs the output of synth to 'complete the messages' in some respect, anyway.

What I do know: there appears to be two way communication, from both directions. I saw it when there was a successful transfer from PC to CZ, on the Mac:

1. PC sends 264 bytes to CZ
2. CZ sends 7 bytes back - acknowledgement? => not sure this part is absolutely necessary, but I definitely saw it in MIDI Monitor app, on *successful* transfer. On unsuccessful transfer, only step 1 (PC to CZ) - no ack.

And as I remember, when initiating a dump from synth to PC:

1. PC sends 10 bytes (dump request)
2. Synth dumps back to PC 

=> this is standard behavior for PC initiating dump request, yes?
And again, for the record: with MRCC 880 and Casio CZ-101, this direction ALWAYS works.

- - -
 As to bright ideas, all I could think of, beyond requesting the ability to set lower buffer size in software preferences (as currently exists in macOS SysEx Librarian), was to add a re-transmission filter between PC and MRCC 880; or in an intermediary computer app, a type of MIDI pipe with filtering -- to re-buffer data and transmit with lower transmit buffer size, suitable for the synth's needs. 

I do not know if this is even possible, nor have I not kept up with any commercial products that might address the need; but it seems kind of silly to do something like that here, when I have already confirmed that setting lower buffer size in software addresses the issue, when used with the MRCC 880. 

It would nice, on reflection, if "Audio MIDI Setup" on macOS allowed setting transmission speed and transmission buffer size universally, per port. Not going to happen, likely.