Yamaha synth (Mo8) not connecting to MacBook Pro via MIDI

Attempting to connect my Yamaha Mo8 Synth/ KB via Midi to record in GarageBand, haven't been able to connect into MacBook Pro. 

Laptop still doesn't "see" Yamaha KB, in either 

1. Audio Devices in "Audio MIDI Setup" window, or 

2. in System preferences > Sound, or

Yet in GarageBand Preferences > Audio/ MIDI > MIDI lists inputs detected when Synth on.

Also popup seems to indicate it recognizes a midi device is connected, 

-- KB is turned on, popup sez Changes: "4 midi inputs available".

-- once KB is turned off, while computer is asleep and turned back on, sez "0 midi inputs available"

Followed these directions from Apple n Wikihow for hours:

- Used both types of USB outputs in back of Mo8. The USB A-B cord (printer cable), which is the manufacturer designated output labeled "to host" on KB.

- Found Sound / Audio Devices in laptop system preferences. 

- Loaded Yamaha's Midi drivers, per Apple insts.

- Found, created Mo8 interface in Midi Device window,

- Tested Midi Config of Mo8 KB, in Midi Test Setup window several times...

(no connection sound indicator heard as stated).

PLEASE HELP! Thanks, JW