>> >> Sorry, I should have done a bit more testing. I've >> just verified this: pmidi data IS echoed, so long as >> someone is listening. The /proc/asound/card1/midiD0 >> statistics don't update received bytes if no one is >> listening. >> >> So it looks like I have *another* bad cable. This >> one lets me send MIDI data, but not receive :( >> >> Moral of the story: don't waste time with cheap >> cables. I'll get one with proper electronics (I >> don't know what "opto-coupling/isolation" is but it >> suddenly looks very important). >> Hi,
as for midi wiring: all signals inside the computer are defined as voltage levels relative some ground (the black wires from the bower supply, some extended metallic area on the mainboard, ....) Midi defines signals as current levels without reference to any ground, and those opto elements help to keep midi instrument ground and computer ground separate. This was done to ensure that connecting the keyboard to the computer would not introduce that pleasant 50 hz powerline sound into the audio system Midi cables always have male plugs at both ends - there is no "extension" type male / female cable. To bridge that gap, some good music instrument stores (do not even ask at a computer shop) sell a female-female adapter. This is the only way to connect a keyboard if those 50 cm or so at the joystick / midi cable are too short. If you plug one of these between the two midi connectors on the suspect cable and het no echo, while running a wire right at the 15 pin connector creates midi echo, it is definitely a bad cable. If you do get a signal from this echo test, the keyboard electronics may be broken or not up to specs Wolfgang Hamann ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
