Japanese mobile phone giant NTT DoCoMo said on April 1 that it resumed a service allowing customers to change carriers while keeping their phone numbers, after massive transactions paralysed its computers.
Japan's largest mobile company was forced to halt the service on March 31 night for about 80 minutes after a flood of applications for sign-ups and cancellations paralysed its computer system, it said in a statement.
The launch last year of the number-portability system - which lets users switch carriers but keep their phone numbers - sparked fierce competition among three major mobile phone carriers in Japan, NTT DoCoMo, KDDI Corp and Softbank Mobile Corp to win and keep customers.
"We've been temporarily suspending procedures related to number portability, but operation on April 1 came back to normal as we repaired our system," DoCoMo said.