A wireless device is described that comprises a spread spectrum radio-frequency (RF) communications portion, such as a Bluetooth module, and an ancillary RF receiver portion. The spread spectrum RF communications portion is activated on receipt of a characteristic RF signal by the ancillary RF receiver portion. The ancillary RF receiver portion may consume substantially less power than the spread spectrum RF communications portion thereby allowing a low power standby mode to be implemented. The wireless device may be a measurement probe, such as a temperature probe, for use with machine tools and the like. An interface for transmitting the characteristic RF signal is also described.