The most important characteristics in an electronic cable are impedance , attenuation , shielding and capacitance . In this article, we can only review these characteristics very generally, however, we will discuss capacitance in more detail. At low frequencies the impedance is largely a function of the conductor size, but at high frequencies, conductor size, insulation material and insulation thickness all affect the cable's impedance. Matching impedance is very important. If the system is designed to be 100 Ohms, then the cable should match that impedance, otherwise error-producing reflections are created.
Attenuation is very dependent on signal frequency.
A cable that works very well with low frequency data may do very poorly at higher data rates. Cables with lower attenuation are better. Shielding is normally specified as a cable construction detail. Shielding effectiveness is very complex to measure and depends on the data frequency within the cable and the precise shield design. A shield may be very effective in one frequency range, but a different frequency may require a completely different design.