With the increasing number of subscribers in large cities, it became more and more difficult to offer exchange service smoothly with the magnetic switch. It was decided to introduce the common-battery switch. In 1903, the common-battery switch was first used experimentally in Kyoto because the cables in switching offices were silk- and cotton-shielded cables, which were affected by weather conditions, and Kyoto is surrounded by mountains on all sides so that even in summer the humidity is comparatively low. After that, the switch was introduced in Tokyo and Osaka and spread to other cities. Its heyday was in the Taisho Period. But many switches were destroyed during the Great Kanto Earthquake in 1923, providing the opportunity to replace them with automatic switches.

---