How do I bind auxiliary devices like door switches to the e7w thermostat?

To bind an S541.RF door, window, or balcony switch, enter Service Mode and select the Io parameter. Set the I/O value to the required map number (0 for entry door, 2 for window or balcony). Press FAN to initiate reverse binding, then press the S1 switch on the S541.RF device. When binding completes, the device LED will flash and the e7w will beep, confirming successful binding.