Korg SP300 no midi signal at all

[saberbe]

Hi,

I tried hooking up my SP300 as a midi-keyboard for the first time.

SP300 > Roland UM-ONE > Mac

But the data indicator lights don't show anything at all if i strike keys.

I tried switching the midi channel, holding the transpose/function in combo with the C2 --> C3, but that didn't work.

Any ideas on how to solve this?

Thanks in advance.

Michael