Method B is used for testing links for which the connector loss is a significant portion of the total attenuation. This is the case for premises links. The referencing procedure for Method B uses one patch cord per fiber link to be tested.
This method only works if the link you are testing has SC connectors at each end.
However, when using Method B, be aware of the following shortcomings:
When going from the reference setup to the test setup, it is necessary to disconnect one end of the patch cords from the tester. It is very important to never disturb the connection at the OUTPUT or source end. If this connection is disrupted, the reference is lost, and proceeding without re-referencing will seriously compromise the test results. Unfortunately, one could easily disconnect the patch cord from the source (OUTPUT) end instead of from the detector (INPUT) end.
Although you must disconnect the patch cords from the detector (INPUT) end of the tester, extreme care is required as dirt and other elements can cause damage to the detector.
To test SFF connectors that have to transmit and receive fiber in the same connector, you are forced to disconnect from the source (OUTPUT) end in violation of proper referencing and test procedures. In this case, Method B Adapted should be used.
1) Setting the reference:
2) Once the reference has been set, remove the patch cords from the INPUTS ONLY as shown below:
3) Add a known good patch cord to the two inputs:
4) Connect to the fiber link to be tested:
The adapter count in the DSP in this case should be 2; there are two adapters per fiber ADDED AFTER the reference was set.