The 4-pin IR sensor header is just at the top left of this picture, labelled "IR_HEADER1" on the board. The hole behind the front panel where the IR Sensor Module clips in can be seen at the bottom right, above the front panel power switch, and below the black wire leading back from one of the WiFi aerials mounted behind the front panel. An optional Mini PCI TV Tuner Module can be fitted in this area of the board (board is labelled "MINIPCIE2").