Nippon Electric Company LA-1

Interestingly, although NEC is a Japanese company, the characters engraved on the front of the microphone are Chinese. NEC entered the Chinese market in 1908, driven by the implementation of a telegraph treaty between Japan and China.

You can read more about the history of the NEC company here.

This is a Reisz carbon microphone very similar to that made by the Marconi company in the UK, and was possibly made under license in Japan. The body of the microphone is marble, with a bakelite front panel and perforated metal grill, which protect what would have been a mica or possibly rubber diaphragm. Behind the grill is a shallow recess which holds the powered carbon or coal dust, with a carbon electrode at each end of the hollow. The electrical connection is made via two screw terminals at the rear of the microphone. Four hoops on the sides are used to suspend the microphone within a hoop or ring

The carbon granules can move and settle into position over time. Two screw holes in the top of the microphone are available to add extra granules if required. The Marconi branded Reisz microphone has three such holes.