Nippon Telegraph & Telephone Corp plans to start a low-cost Internet access service in December for individual users in Tokyo. It will apply to the Ministry of Posts & Telecommunications for permission to launch the service. The Open Computer Network service will enable users to access the Internet over existing phone lines for up to 15 hours a month for $20, less than the cost of most other such services available in Japan. It also plans to lay dedicated lines for low-speed computer network transmissions from December; the dedicated line service will first be offered in just two regional cities, Fujisawa in Kanagawa Prefecture and Ogaki in Gifu, but will be expanded early next year to 11 other cities, including Tokyo. NTT said the service will cost $333 a month, about half the cost users now pay for a dedicated line.