A distribution line carrier communication have merits in no need of dedicated communication lines. But a transmission data rate of existing practical systems in phase-to-phase coupling is 60bps and it is low. In order to realize high speed rate we measured signal transmission characteristics of actual disribution systems from 1kHz to 10kHz and compared them with calculation values. Also we measured noise characteristics in distribution lines, simulated a signal to noise ratio in PSK modulation and studied the possibility of practical high speed data transmission. As the results, it is possible to get S/N 20db, and bit error rate of 10-5 or less for 1200bps data transmission rate, in case that transmitting power is 20V per one phase, carrier frequency of 3kHz up to 4kHz, if the countermeasure to near phase advance capacitor is applied.