Small Form Factor Connectors, Bi-directional Testing
|True duplex connectors (MT-RJ, VF-45, Fiber Jack) cannot be swapped at the patch panel. They were deliberately designed so that you (really, the enterprise user) cannot plug them in backwards. This makes bi-directional testing extremely hard. |
In the view of makers of MT-RJ equipment, plus 3M and other makers of VF-45 equipment, bi-directional testing is unnecessary because all of the MT-RJ transceivers are made the same way, with transmit and receive always in the same orientation. Our instruction sheets for these SFF kits were carefully written to match the correct polarity.
There will be users wanting to do it, but the point here is that the designers of this stuff do not support bi-directional testing because they don't see the point. "You test the links in the directions they are going to be used! Why would you waste the time testing it in a direction that you cannot even hook it up?"
For customers who insist on testing each fiber each way, interchangeable adapter caps on the meter and source do nothing to solve the problem.
For Fluke Networks customers, who insist on bi-directional testing of true duplex links, there are 2 choices, both ugly:
1. Make two passes.
a. Use our SFF kit. Set the reference per the instruction sheet.
b. Test one direction on all duplex ports, using normal practice as described in the instruction sheet for the SFF kit.
c. Swap patch cables AT THE FTA ports and re-reference.
d. Test the other direction.
2. Use extra patch cables to enable bi-directional testing on the cable tester. It may be a nasty mess of extra patches, but it gives method B equivalent results in a single pass and saves the bi-directional results under the same cable ID.