Nippon Telegraph and Telephone Corp. is considering halving its fixed monthly charge designed for heavy Internet users -- now in a trial phase -- from the current 8,000 yen to around 4,000 yen as early as April, NTT officials said Tuesday.

The move came in response to a greater-than-expected number of users shifting to such services during the past couple of months, they said. Competition from cable television networks and Internet access services planning to utilize NTT's newly developed asymmetrical digital subscriber lines are also behind the move for a lower charge.

ADSLs are ordinary phone lines having a special modem on each end of a line. Under the current fixed-rate system, experimentally implemented in certain areas in Tokyo and Osaka since November, NTT-East Corp. and NTT-West Corp. are charging the monthly rate of 8,000 yen for those using integrated service digital network for unlimited amounts of time.

Tokyo's Shinjuku, Shibuya and Ota wards as well as Chuo and Kita wards of Osaka and Suita, Osaka Prefecture, have had access to the experimental services. The two operators had initially set a target of collecting 1,000 contracts each for the fixed-rate system. As it turned out, however, more than 1,300 customers of NTT-East opted for the service as of the end of December, with over 300 users remaining on the waiting list due to the limited data-transmission capacity NTT East had prepared for the trial service.

Although NTT-West has yet to reach its target, some 600 customers have signed up for the service. The fixed-rate fee does not include Internet service provider fees.