A surgical robot comprising a base and an arm extending from a proximal end attached to the base to a distal end attachable to a surgical instrument via a series of links interspersed by articulations. The arm comprises a receiver, a proximity sensor and a controller. The receiver is configured to receive data from the surgical instrument over a short-range wireless communications link with the surgical instrument. The proximity sensor is configured to detect the proximal presence of the surgical instrument. The controller is configured to respond to the proximity sensor detecting the proximal presence of the surgical instrument by enabling the short-range wireless communications link between the receiver and a transmitter of the surgical instrument to be established.
