The MM400A is machined from a solid aluminum block to provide an extremely ightweight package with the ruggedness needed in extreme environments. Input jacks and controls are O-ring sealed for watertight protection in wet
environments.
A special non-corrosive finish (same as is used on NASA space vehicles) resists salt water exposure and perspiration in extreme environments. The DSP-based design offers backward compatibility with a handful of earlier analog designs, such as the Lectrosonics 100 and 200 Series receivers, and some other brands of analog wireless receivers. The operating mode (compatibility mode) can be selected with a sequence of frequency switch settings and battery insertions to cycle the power on and off. Only the MM400A transmitter is covered in this manual. Companion receivers are covered in separate manuals.
