To facilitate the use of relatively
high frequency data transmission services over a
wireline communication resource originally deployed to support
low frequency voice band services, an assessment of the
wireline communication resource (50-52) is based on attenuation of
high frequency test signals, of known original level, that are generated (18) injected into the
wireline communication resource from a
test point (12). A
detector (60) at a potential
point of service, e.g. at a customers' premises (14), detects an attenuated level of the test signals and generates a
control signal (70, 82), such as a drive current, indicative of the attenuation caused by the wireline communication resource (50-52). The
control signal (70, 82) is then indirectly communicated back to the
test point (12) in a coded form, and preferably within a voice band transmission. The coded form may be realized as modulation of a power supply provided to the customers' premises by the wireline communication resource, or could be achieved by up-link
frequency mixing. In its most basic form, the
control signal causes fluctuation on a visual level indicator at the customers' premises and therefore relies on a customer providing a verbal or toned response to the
test point as to the level of the visual indicator. Effective attenuation at high frequencies can then be assessed based upon analysis of information coded into the voice band
signal and its direct relationship with the original level of the injected
high frequency signals.