Shōjidō kōkanki
Subtitle: Denwa kikai hen
By: [henchosha Jitsuyō Tsūshin Kōgaku Sōsho Iinkai]
Edition: 4-han
Publisher: Denki Tsūshin Gakkai
Published: 1947
Place of publication: Tōkyō
Language: jpn
Number of pages: 34
Subjects: Telephone switching sustems, Automatic,