Using enums inside a switch statement Java

Question

I'll make it short and quick. I have an enum that represents "commands", the commands are sent of the net so they're translate from chars to bytes -

public static enum Command {

    EXIT('E'),
    PLAY('P'),
    OK('O'),
    ROTATE('R'),
    FORWARD('W'),
    BACKWARD('S'),
    LIFT('L'),
    TURRET('T'),
    FIRE('F');

    private final byte command;

    private Command(char command) {
        this.command = ((byte) (command & 0xFF));
    }

    public byte asByte() {
        return command;
    }

    public char asChar() {
        return (char) command;
    }

}

But, for some reason I'm getting the following error while trying to "switch" them -

constant expression required

Here is the switch statement:

 public void readData(byte[] data) {   

    switch (data[0]) {
        case Command.PLAY.asByte():
            sendCommand(new byte[]{Command.OK.asByte(), 0});
            break;
    }
}

The switch isn't complete due to the error.
Any help would be welcomed.