TOKYO (Standard&Poor's) Feb. 20, 2013--Standard&Poor's Ratings Services today said it has assigned its 'AA' debt rating to Japan-based telecommunications company Nippon Telegraph&Telephone Corp.'s (NTT; AA/Negative/A-1+) $500 million euro secured bonds, due Feb. 26, 2020. The ratings on NTT reflect its leading position in Japan's major telecommunications and broadband markets, and its high profitability and top market share in its mobile business, which is a pillar of the company's earnings. Also, NTT is by far the largest fiber-to-the-home (FTTH) service provider in the broadband business in Japan. We also factor into our ratings the company's system integration business, which increasingly contributes to its total earnings, and its extremely strong financial base, supported by the company's