KDDI Corporation (KDDI株式会社) is a Japanese telecommunications operator. It was established in 2000 through the merger of DDI Corporation (第二電電), a long-distance communications company; KDD Corporation (ケイディディ), Japan's former state-monopoly international telecommunications provider; and Ido Corporation (日本移動通信), a mobile network operator.
In 2001, KDDI fully integrated its mobile operations by absorbing the regional companies of the DDI-Cellular Group, unifying them under Au brand. It currently stands as the second-largest mobile telecommunications provider in Japan in terms of the number of contracts, following NTT Docomo.
KDDI provides mobile cellular services primarily using Au brand, alongside its sub-brands UQ Mobile and Povo. ISP network services are provided under Au One Net brand, while Au Hikari is the name under which its Fiber to the Home (FTTH) services are marketed. Historically, the company also offered ADSL broadband (ADSL One) and IP telephony over copper (Metal Plus), but these legacy services have since been discontinued.
History
On April 1, 2002, au by KDDI launched 3G networks using CDMA2000 1x technology.
On November 28, 2003, au by KDDI launched EV-DO Rev 0 service in the "CDMA 1X WIN" brand, and revolutionized Japan's mobile telecommunication industry by introducing fixed rate data subscription plans at a data rate of 2.4 Mbit/s.