Hi Glen. Sorry for the long delay, but I was at my cottage and the standard MIDI cable was at home.
As soon as I arrived home yesterday, I hooked up the Altura to my old Casio keyboard per your suggestions. It worked perfectly! I stopped working for a bit and played instead. This thing is great! Back to work–I again tried to get the Altura to work as an instrument on my computer workstation, connected by a MIDI to USB cable. I first connected the Casio keyboard to the workstation. The workstation reports a MIDI device connected, and the Casio keyboard then plays fine through the workstation. There is a MIDI activity lamp on the USB cable which blinks when MIDI commands are sent. Then I disconnected the cable end at the Casio and plugged it into the Altura. The workstation indicates that it detected an instrument, but no sound plays, and the MIDI activity lamp on the cable stays dark as I play the Altura. Switching back to the keyboard, the workstation reports the change, and the keyboard again plays and the MIDI activity lamp blinks. I also tried plugging the cables in and then reloading the workstation each time, in case plugging and unplugging was confusing the workstation.
I would suspect the MIDI to USB cable, but it works fine with my old keyboard! Not quite there yet…