Fluke OF-500-10 Technical Reference Handbook page 264

OF-500 OptiFiber Certifying OTDR
Technical Reference Handbook
Method C/A.3
Method C/A.3 results account for the loss of only the
fiber in the link. This method is suitable for testing links
where the fiber's loss is the majority of the total loss, such
as when the link is very long or patch cords are not used
at either end. Method C is defined in the ANSI/TIA/EIA-
526-14A multimode standard. Method A.3 is defined in
the ANSI/TIA/EIA-526-7 singlemode standard.
Method C/A.3 reference connections cancel out the
effects of two connections and three reference test cords
in each fiber path, as shown in Figure B-3.
B-6
The test connections add the fiber in the link to each
path. Loss results for Method C/A.3 therefore represent
only the fiber in the link.
Because the results omit both connections in the link,
ANSI/TIA/EIA-526-14A and 526-7 do not recommend
these methods for testing premises fiber, where patch
cords are typically used at both ends of the link and
connector loss is a large portion of the total loss.