An integrated circuit device for an electronic equipment having an internal bus, the integrated circuit device comprising a plurality of input terminals, a switch circuit connected to the plurality of input terminals for selecting any one of a respective plurality of input signals via the plurality of input terminals, a switch control circuit for controlling the switch circuit to select any one of the input signals in dependence on a selection signal, an analog-to-digital converter for converting the selected input signal from the switch circuit into a corresponding serial digital signal, and a bus interface circuit connected to the internal bus for sending the serial digital signal from the analog-to-digital converter to the internal bus and for sending the selection signal from the internal bus to the switch control circuit.