An electrosurgical connection unit for a surgical robot arm to connect an electrosurgical instrument attached to the arm to an electrosurgical generator. The electrosurgical connection unit includes an input port connectable to the electrosurgical generator, the input port configured to receive a driving electrosurgical signal and output one or more activation signals; an output port connectable to the electrosurgical instrument, the output port configured to output the driving electrosurgical signal received on the input port; one or more activation switch units, wherein activation of an activation switch unit causes an activation signal to be output from the input port indicating a driving electrosurgical signal with a desired waveform is to be activated; and a control unit configured to selectively activate one of the one or more activation switch units in response to a control signal.