What must be subtracted from the far-end crosstalk measurement to determine the ACR-F value?

To determine the ACR-F (Attenuation to Crosstalk Ratio - Far End) value, the key element is to subtract the insertion loss from the far-end crosstalk measurement.

The ACR-F is a measure that helps in assessing the quality of a transmission medium by indicating how much of the signal remains usable when compared to the noise and interference it encounters. Insertion loss represents the reduction in signal strength as it passes through a device or medium. Therefore, to obtain a valid ACR-F value, it is essential to account for the insertion loss, as this directly influences the effective signal strength measured against crosstalk.

This subtracted value allows for a more accurate depiction of performance as it factors in how much of the original signal is lost due to the medium itself, thus providing a clearer picture of the actual margin between the signal and crosstalk present at the receiving end. The calculation effectively helps identify the integrity of the transmission link in a networking scenario.