Casio CZ/ VZ/ FZ - Pro Series

Hi Steve,

I think you are too focused on these vintage numbers like 31250 bps and 115200 bps. Transferring sysex by USB and MIDI are not limited to these old numbers. USB enables speeds that are hundreds or thousands of times faster than these numbers. In fact, greatly higher speeds are touted as one of the benefits of a USB MIDI device (along with multiple streams).

High speed sysex transfer is both desired and encouraged, for example, in the case of sending sound data to a sampler. If you wanted to send 128 megabytes of sounds to your sampler, and if you were restricted to 31250 bps, it would take 9.5 hours to send the sounds. USB MIDI devices enable higher speeds, and that speed is encouraged.

31250 bps is the speed of an old dialup modem (actual throughput) on a good day. If you tested at 115200 bps, that is merely 3.7 times faster than 31250 bps. Still very slow by today's standards.

USB 2.0 has a max throughput of something like 35 MB/s. But lets be generous and say that in the real world, you can only get your USB 2.0 to 20 MB/s. That speed, 20 MB/s, works out to 160,000,000 bps, which is 5,120 times faster than 31250 bps.

So yes, I think a capable modern computer with a good USB system can send sysex out faster than the CZ can deal with it. And it's not necessarily tied to CPU speed of the computer either, more like the speed of the whole computer-USB system.

You will probably find it enlightening to read the "Universal Serial Bus Device Class Definition for MIDI Devices", Release 1.0, Nov 1, 1999, which you cand download here:

http://www.usb.org/developers/devclass_docs/midi10.pdf