Fluke DSX-8000 - 67 Db Rule for ACR-F and PS ACR-F

Chapter 3: Certify Twisted Pair Cabling
About dB Rules
153
67 dB Rule for ACR-F and PS ACR-F
At frequencies where FEXT or PS FEXT is less than 67 dB, ACR-F or
PS ACR-F are not evaluated against a limit. See Tables 4 and 5 for
applicable limits.
70 dB Rule for ACR-F and PS ACR-F
These rules applies to all channel or permanent link test limits
where ACR-F is measured.
At frequencies where FEXT or PS FEXT is less than 70 dB, ACR-F or
PS ACR-F are not evaluated against a limit. See Tables 4 and 5 for
applicable limits.
75 dB Rule for ACR-F and PS ACR-F
These rules apply to TIA Cat 8 limits at frequencies above
200 MHz.
At frequencies where FEXT or PS FEXT is less than 75 dB, ACR-F or
PS ACR-F are not evaluated against a limit. See Table 4 for
applicable limits.