The effort of rebuilding after the Great Kanto Earthquake became the opportunity for a gradual conversion from manual switching equipment to automated exchanges. The first automatic telephones are of Type A and Type H, each connected to a switchboard of the same type. As more telephone sets are added, the No. 2 common-battery telephone is combined with a No. 1 dial, but this model produces considerable receiver noise during dialing. In Showa 2(1927), an improved No. 2 dial is developed for use in the No. 2 automatic telephone set which functions with both Type A and Type H equipment.