TD-27: I am able to transmit and receive audio via USB, however MIDI is not transmitting or being received.

If you're not able to transmit or receive MIDI via USB, check the MIDI Tx/Rx Switch in the TD-27 and make sure it is set to "ON." 

1. Press the SYSTEM button.
2. Cursor to highlight "MIDI," and then press ENTER.
3. Cursor to "MIDI Tx/Rx SW."
4. Turn the dial to choose "ON." 
5. Press the DRUM KIT button when you're finished. The new setting is saved automatically. 

Note, from the factory, the TD-27 is on MIDI channel 10, so make sure your software is setup to receive on this same channel, or change the MIDI channel to match it.