What the thread found

• BFD analog receiver units and Teradek units use the same power connector type but with opposite polarity wiring, and using the wrong cable damages the equipment.
• A BFD handset with its 9V battery removed can serve as a polarity tester by plugging in the power cable and observing whether it powers on.
• The handset must have its battery removed before testing to avoid false positives from battery power masking a reverse polarity problem.
• A custom cable tester can be built using a 2-pin Lemo socket, a 1.2K resistor, and a bidirectional red/green LED, which displays green for BFD polarity, red for Teradek polarity, and no light for broken cables.
• A multimeter can test polarity by using a female D-tap adapter connected to a 2-pin Lemo plug end for easier probe access than directly contacting the small connector pins.

Depends on

• The handset testing method applies to BFD handsets specifically, which have reverse polarity protection that the receivers lack.
• The custom cable tester circuit values and component specifications are provided but building one requires soldering skills and electronics knowledge.
• Testing requires access to a power source for the custom tester or a BFD handset for the field method.

Gear in this thread

BFD

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