<p>The present invention relates to a control system for operating a crane (101). The control system includes a central control module (125) for controlling operation of the crane (101) and a control unit (121) for outputting control signals to the central control module in response to user inputs. At least one portable safety unit (149) having a wireless transmitter for communicating with the central control module (125). The at least one portable safety unit (149) is provided with a safety module which is connected to the wireless transmitter. The safety module can be operated to transmit an inhibit signal wirelessly to the central control module (125) to inhibit operation of the crane (101). The present invention also relates to a crane (101) and a method of operating a crane (101).</p>
