A Milliwatt test (Milliwatt line) is a test method or test facility used in telecommunications to measure line quality and transmission loss between stations or points in an analog telephone system. The test consists of transmitting an analog sinusoidal signal at the frequency of 1004 Hz with the power level of 0 (zero) dBm. By definition, this is the equivalent of a continuous power dissipation of 1 mW (milliWatt), i.e., the power consumed if a voltage of 0.775 V(RMS) is applied to a telephone line with 600 Ohm nominal impedance.