A service request system comprises a number of request units (5) located
within a service area (1), a number of receivers (4), a location unit and
a display. The request unit comprises a manual control and wireless radio
transmitter and sends a radio request for service signal in response to
operation of the manual control. A receiver receives a request for
service signal and reports reception of the request for service signal
and the relative position, relative to itself, of the request unit to the
location unit. The location unit derives the location of the sending
request unit within the service area from the report and relative
position and shows this location on the display.