Methods and apparatus are provided for transmitting alternate-polarization phase-shift-keyed data. A backlight 2 for illuminating a liquid crystal panel 3 from the rear, is formed by combining a plurality of backlight units 10, 10,. The method also includes, but is not limited to, calculating a cold junction temperature of a terminal for at least one thermocouple channel carrying the thermocouple signals based on measured or calculated temperature values of the terminals, or a combination thereof. The wireless communications device disables the transmission when the signal strength falls below the predetermined threshold.