Keymaps: Traditional: Two rows of the traditional layout. Q is C2; C is Middle C.
Jankó: Two rows of the Jankó layout. E is C2; C is Middle C.
Wicki-Hayden: Four-row Wicki-Hayden layout. G is Middle C.
Alphabetic: Keyboard keys A - Y correspond to notes C3 - C5.
M is Middle C.
(Should be familiar to TRS-80 veterans.)