For twisted pair cable, users are most concerned about its performance indicators. These include attenuation, the near-end crosstalk, impedance, capacitance, DC resistance, etc.
(1) the attenuation (Attenuation) is a measure of signal loss along a link. Relationship between attenuation and cable length, with increasing length, signal attenuation increases. Attenuation with "DB", source-side signal to receiver signal intensity ratio. Because of changes with frequency, and therefore, within the scope of application should be measured in all of the frequencies of attenuation.