When recording digital data corresponding to a voice signal, a voice data recording and reproducing apparatus generates an error correction code and records this code together with the digital data in semiconductor memory. The other electron-emitting device where the electron-emitting region contains fine particles being arranged at gaps of from 5 to 100 and having average particle diameter of from 5 to 1000 is also disclosed. The respective CMTS devices are connected to each other by means of a synchronization bus. The protective layer is composed of one or a plurality of inorganic films, and at least one of the one or plurality of inorganic films is an SiON:H film having stretching-mode peak area ratios, as determined by infrared absorption spectroscopy, that include an absorption area ratio of N\u2014H bonds to Si\u2014N bonds in the SiON:H film which is not less than 0. The compound of the present invention shows superior immunosuppressive action with less toxicity and higher safety, and is useful as a drug for prevention or suppression of rejection of organs or bone marrow transplantation, or as a drug for prevention or treatment of various autoimmune diseases or allergic diseases.