There is provided a wavelength stabilizer for stabilizing the wavelength of an optical signal oscillated from a laser diode in each of a plurality of channel transmitters in a WDM optical transmission system. The exhaust treatment device may have a housing, and an injector disposed within the housing to deliver an injection fluid into a flow of exhaust. When an AMR system wishes to retrieve data from a large number of points over an AMR network, a broadcast or multicast request is transmitted to appropriate nodes. Lock cannot be cut with bolt cutters or pried off.