Abstract: A payment card holder comprises a holding device for realeasably engaging with a payment card, a detection device for detecting the presence or absence of a payment card in the holding device, and an alarm device operable to receive a detection signal from the detection device and to enter an alarm condition when that detection signal is indicative of absence of the payment card in the holding device. The alarm device comprises a memory device for storing audio data, a microprocessor operable to output an audio data signal derived from stored audio data retrieved from the memory device, when the alarm device is in the alarm condition.

Abstract: A device (5) for connecting an audio device to a radio frequency receiver (1) comprises an audio signal input (9), an encoder connected to receive an audio signal from the audio signal input and operable to generate an encoded radio frequency signal from a received audio signal, and an output for direct connection to an antenna connection of an radio frequency receiver.