Q: What is the best way to compare category cables from different manufacturers?
A: There are a number of ways. It depends on what is most important to those buying it. Regarding electrical performance, Attenuation to Crosstalk Ratio (ACR) can be a good parameter to base cable selection on. ACR is the relationship between signal strength and noise. As the signal strength increases, so does the noise. At some point, the noise overcomes the signal and corrupts it. Just like turning a stereo speaker up too loud can cause it to fail. The higher up the frequency ladder that the ACR value remains positive, the better the cable is in that respect. For example, a Category 6 cable that has a positive ACR value out to 350 MHz would be considered a better cable than one that has a positive ACR value out to 250 MHz. This extra performance may be useful for a particular application or may be helpful if the installation environment is challenging. Typically, additional cable performance above what the standards require provides a cushion in the event of a difficult installation or sub-par connectors and patch cords.
Near-End-Crosstalk (NEXT) is also a good measure of a cable quality. NEXT is the jumping of signal from one pair of conductors to an adjacent pair with a cable. A cable with a higher NEXT value than another, at a given frequency, would be a higher performing cable.