A portable communications device comprises an interactive touchscreen display (20) having a transparent outer surface member occupying substantially all of a front surface of the communications device. A casing provides a rear surface of the communications device. The device further comprises an audible sound transmitter and an audible sound receiver arranged so as to receive vocal sounds produced by a user when the device is placed against the user's head. An ultrasonic transmitter (24) is separate from the audible sound transmitter. An elongate aperture (28) has a minimum dimension less than 100 μm located between the transparent outer surface member and the casing. A channel connects the elongate aperture and the ultrasonic transmitter so as to permit ultrasonic signals to pass out of the elongate aperture.