1890
    		• Magnetic Single Switch (First Switch in Japan)
    1891
    		• First serial duplex exchange trials
    1898
    		• Magnetic Parallel Compound Switch Adopted
    1903
    		• First Common-Battery Switch in Japan Adopted at Kyoto Office
    1912
    		• No.1 Large Common-Battery Long Distance Switch Adopted
    1926
    		• Japan's First Automated Switching Equipment (Introduction of Type A Switchboards)
    		• Japan's First Automated Switching Equipment (Introduction of Type H Switchboards)
    1927
    		• The No. 3 Large-Scale Common-Battery Intercity Exchange
    1955
    		• Crossbar switching equipment
    1959
    		• Crossbar automatic exchange introduced for long distance calls
    1972
    		• D10 Electronic Switching Equipment
    1982
    		• D60 Electronic Switching Equipment
    1983
    		• D70 automatic exchange (LS) starts operation
    museum@mod.hqs.ntt.jp