Abstract: A detector (101) for detecting smoke from a fire and generating an alarm has a detection chamber (105) in which a light source (111) and a light detector (113) are arranged. In normal use, the light detector (113) only receives light from the light source that has been scattered by the presence of smoke in the chamber (105). When testing the detector (101), the light detector (113) receives light from the light source (111) by presenting a reflecting surface (129a) of a rotor member (129) to reflect light from the light source (111) towards the light detector (113). In normal use, the rotor member (129) is positioned so that the reflecting surface (129a) no longer reflects light from the light source (111) towards the light detector (113).

Abstract: A printing network including at least one user workstation and a printer is described. The user workstation transmits print jobs with image controller commands having data which is representative of a network address of the user workstation. An image controller at the printer receiving the print job executes the image controller commands in the print jobs to extract the network address of the user workstation. Processes in the printer store the extracted network address of the user workstation in association with data representative of the print job. The printer transmits messages to the user workstation concerning the status of the print job using the network address extracted from the print job.