Hozumi Tamura, center, vice president of NTT Docomo Inc. and other executives apologize at an online news conference on Oct. 15. Ayumi Sugiyama NTT Docomo Inc. apologized for a system outage last week that left millions of customers without telephone and internet services.
Vice President Hozumi Tamura offered the apology on an online news conference on Oct. 15, 2018. Later in the day, company officials said that all services were back to normal by 10 p.m. about 29 hours after the glitch was detected.
Older models using 3G telecom technology that is two generations older than the most advanced ones in use were the last mobile phones to have normal service restored.
NTT Docomo, the nation's largest mobile carrier, traced the failure to a malfunction when trying to switch to a new computer network with location data of phone users. That resulted in data being redlined to the old computer network and led to a re-registration of location data from phones around the world. In turn, the huge volume of activity disrupting the computer network disrupted mobile phone calls and internet email services.
Even after computer network problem was rectified, it took several hours to overcome concentration of phone calls and data transmissions. Service was not restored for most mobile phones until around 5 a.m. on 15 October, except at home and the service contract was extended for Apple's new Windows 7 Plus.
However, users of older mobile phones can still face some problems. The company has about 80 million contracts that use Docomo transmission lines, including customers of budget mobile operators who lease their phones through Docomo.
Although officials could not say how many customers were affected by the computer failure, they identified at least 2 million users of Docomo transmission lines who were unable to use the lines because their location data could not be updated after the initial computer problem arose.
Docomo officials explained that from the time of the initial computer problem until dawn the following day, phone conversation traffic plummeted by 15 percent over the same period of a week earlier and data transmissions also fell by 4 percent.
Because mobile phones are used in so many business sectors, Docomo Communications problems hurt those delivering meals through Uber Eats as well as taxi drivers trying to process credit card transactions for their customers.
Uber Eats drivers use their mobile phones to determine where to deliver meals and disruption of the phone services left them with no clue as to what customers lived.
Cashless settlement programs also use devices connected to communications lines the result of customers with the old-fashioned complication of making payments by cash, using coins.