How to Control both PC and Hardware via USB at the same time.

[moneyman]

Each of the USB ports has a pair of buttons (guessing maybe what you're calling a / b and c / d?) of which the left one selects your source / input, and the right one your destination / output, as needed.  Once you've selected a source, until you select a new one, any destination you select will be added.  In your case, if the keyboard is on USB A, press the left button (you should notice the possibility to choose one of the first four numbers in the output section while you hold the button; these are 4 virtual USB input ports in case a device can use them, but for most gear, #1 is the only one that will work).  Now that you've chosen the source, pick as many destinations as you want.  For the hardware connected to USB B, just press the right button to select it, and that should complete that routing.  You said the PC is already good to go, but the principle is the same, press the right button on the USB device port (while holding it you can choose any of the 12 virtual ports going to the computer using output buttons 1 to 12).

Hope that all makes sense.  If I follow what you are saying and the diagram, it looks like your 1 + 2 are MRCC ports A + B, and your letters are the left / right pairs, and if that's true, then what you've labelled 2c is another input, not the destination, so it may be you were off by one button.

Got it thanks. made the connection as you mentioned. But it still doesnt work. A in is going to C out. But no midi signal is being sent from C to external hardware. Are there other settings I need to tweek?

Best