Focusrite iTrack Dock and Roland A-49
The Roland A-49 controller keyboard receives power exclusively from the UBS port. But in the factory setting, the POWER indicator only lights up if it receives power and compatible data communication. So the indicator lights up if the USB cable is connected to a computer's USB port. But it doesn't light up when:
For this we have to make two changes to the keyboard:
The User Manual has an instruction for changing the driver but it is useless without it being in autonomous mode.
Change the operating mode to "Stand-alone mode"
Press and hold the Function, Assign and Pitch buttons, and connect the USB cable to a power source. The POWER indicator lights up whenever the keyboard is connected to a powered USB port.
Change from "Dedicated Driver" to "Generic Driver"
With the keyboard on, press the keys in the following sequence:
Function -> ADV -> [-]
Disconnect the USB cable and reconnect it.
The keyboard now works on an iPad and iTrack Dock.
If you want to reconnect the A-49 to a computer where you have already installed the driver for Windows or Mac OS X, reset the keyboard with the "Dedicated Driver". To do this, repeat the previous sequence replacing [-] with [+].