An assessment of subscriber loop copper pairs for digitised data transmission includes capturing the effects of noise such as crosstalk, background noise and impulse noise on the quality of transmission. In the paper we present results of a subscriber loop noise measurement survey conducted within GTE. Calibration for impulse-noise field measurements, which estimate impulse arrival rate λ and the standard deviation of the impulse amplitude distribution, σv, are also described. The effect of noise on the performance of a digitised loop is discussed.