I bought this for my son to connect an old old Yamaha home keyboard to a PC to use as a MIDI keyboard. Note-on worked, note-off didn't. Tried it from my Roland A-88 into an iMac and PC, no problems at all. Automatically set itself up, appeared in various DAWs (Logic, Sonar and Ableton Live) straight away.
No way of telling if there is a fault with the Yamaha keyboard or it's just not talking to the cable as it should. I'd imagine its the former, as MIDI spec hasn't changed since 1983, but if you're buying this to work with older home keyboards with MIDI sockets but no USB, bear in mind that it may or may not work.
I've had a bunch of these MIDI-to-USB cables off Amazon over the years and sometimes it's pot luck whether they work at all. At least this one works ok with more modern MIDI gear, not that it's much use when modern gear generally has USB.
I've kept it rather than returned it as it's a useful 'utility' thing to have in the Box Of Random Cables. Plus, I must say, it looks really good when it lights up! ;)