Abstract: A selective call system comprising a primary station (10) and a plurality of secondary stations (12), such as paging receivers, has provision for the primary station sending to a predetermined secondary station a qualifying call from which data, for example loyalty points, can be determined and credited to the user of a secondary station. In one embodiment, the primary station (10) receives the data and compiles a point-to-point qualifying call which includes a field containing the data and the identity code of the predetermined secondary station. Optionally, a security field and a checksum may also be included in the qualifying call compiled. The addressed secondary station (12) decodes the received qualifying call and determines the data which is stored in a non-volatile store (48) which accumulates the items of the data. The user of the secondary station is able to display the data held in the non-volatile store (48) on the secondary station's own display panel (42).

Abstract: A collision detector for a vehicle, comprises a waveguide which is locatable on and acoustically isolated from the vehicle. The waveguide allows stress waves to propagate therethrough, and the waveguide is arranged to produce stress wave activity when the waveguide is deformed due to collision. A pair of transducers are acoustically coupled to the waveguide and the transducers convert any stress waves into electrical signals. A processor analyses the electrical signals and gives an output signal to indicate the occurrence of a collision. The transducers detect different frequency bands and the processor compares the electrical signals and indicates the occurrence of a crash if the ratio or difference is greater than a predetermined value. The waveguide is a metallic member which has a glass coating and a protective coating. Alternatively the waveguide may be a fibre reinforced plastic, tin, or a metallic member which has an interface with a semi-rigid plastic member.