June 1, 1990 marks the introduction of an integrated digital communication service, INS-P (packet communication mode). INS-P uses the B-channel or D-channel of an integrated digital communication service for data packet data communications, expanding the possibilities for the use of INS-Net. At the same time, rates are reduced for DDX packet switching services, a system of discounted calling charges is introduced, and a portion of basic phone charges are also lowered.