au

au, also known as au by KDDI, is a Japanese mobile phone operator brand marketed by KDDI Corporation in the main islands of Japan and by Okinawa Cellular in Okinawa. It provides mobile cellular services and is the second-largest wireless carrier in Japan, with 60.398 million subscribers as of March 2021. The brand was established as au K.K. in November 2000 by Kyocera as part of the DDI Cellular network, and was merged into KDDI in 2001, with the brand name retained for all mobile phone services under the KDDI group. au launched nationwide 3G in 2003, began selling the iPhone 4S in October 2011, launched LTE as 'au 4G LTE' in September 2012, and launched 5G as 'UNLIMITED WORLD au 5G' in March 2020. The name 'au' is based on the Japanese verbs for 'meet' (会う) and 'unite' (合う), and KDDI also explains it as standing for 'access, always, amenity' and 'unique, universal, user', with the phrase 'access to u(you)'.

The network that would eventually become au was originally set up as two networks: DDI and IDO. IDO's network was based upon the NTT Hi-cap analog cellular system, and began operations in December 1988 in the Kanto and Tokai regions. DDI's network was run by independent phone companies, and began service in 1989 using the TACS system elsewhere in Japan. Nippon Idou Tsushin (IDO) was owned by Toyota, whereas DDI was owned by Kyocera Corporation. au K.K. (株式会社エーユー) was established in November 2000 by Kyocera as part of the DDI Cellular network. In 2001, the company was merged into KDDI (which had been formed in 2000 by the merger of DDI, KDD, and IDO), but its brand name was retained and applied to all mobile phone service under KDDI group. au established a nationwide 3G network in 2003, replacing its previous cdmaOne service with CDMA 1X WIN (1xEV-DO Rev A) service. It started selling the iPhone 4S from 14 October 2011. The company launched LTE service as 'au 4G LTE' in September 2012. It launched 5G service as 'UNLIMITED WORLD au 5G' on 26 March 2020.

• 2020

  Launched 'UNLIMITED WORLD au 5G' on 26 March.

• 2012

  Launched 'au 4G LTE' service in September.

• 2011

  Started selling iPhone 4S on 14 October.

• 2003

  Nationwide 3G network established.

• 2001

  au K.K. merged into KDDI; brand retained.

• 2000

  au K.K. established by Kyocera in November.

• 1989

  DDI network begins service using TACS system.

• 1988

  IDO network begins operations in Kanto and Tokai regions.

Second-largest wireless carrier in Japan, offering nationwide mobile services under the au brand.

• au mobile phone services

• au 4G LTE

• UNLIMITED WORLD au 5G

1. 1Au (mobile phone company) - Wikipediaen.wikipedia.org
2. 2AO.com launches its own mobile networkretailtimes.co.uk