I don't understand the Garmin wiring diagram for LEMO connectors; they show you running a separate wire from the wire shielding LEMO side, which in turn is terminated to the GMA back shell. This is in addition to the wire shield that is also terminated on the GMA back shell. What is the point of this?
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LEMO Wiring - duplicate shield termination
- Thread starter hoz
- Start date
Desert Rat
Well Known Member
This doesn't look like a duplication to me.
Pin 2 is the ground for your headset connector. It has to go to ground somewhere, so they've chosen to just ground it at the back shell as well.
I don't have Lemo headsets, thats just what I think form looking at the drawing you provided. Or am I not understanding your question correctly?
Pin 2 is the ground for your headset connector. It has to go to ground somewhere, so they've chosen to just ground it at the back shell as well.
I don't have Lemo headsets, thats just what I think form looking at the drawing you provided. Or am I not understanding your question correctly?
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Apologies I wasn't clear; if you look at the RHS of the diagram, you see Headset L and Headset R (pins 3 and 4) go into a 2 core shielded wire, with the shield floating on the LEMO side. However, the diagram calls for a shield drain wire to be created on the LEMO side, and run along the length of the wire and terminated to the back shell on the GMA unit. This is in addition to the shield of the 2 core wire having a shield drain onto the GMA back shell.
What looks like a duplication is that the 2 core shielded wire is shield terminated twice; once by running a (normal unshielded) wire outside the 2 core shielded wire and terminating it onto the GMA, and another by terminating the actual shield onto the GMA.
What looks like a duplication is that the 2 core shielded wire is shield terminated twice; once by running a (normal unshielded) wire outside the 2 core shielded wire and terminating it onto the GMA, and another by terminating the actual shield onto the GMA.
I think that is because the pre-wired LEMO socket (a Bose product) has this additional drain wire built in. Garmin has decided the best thing to do with it is to connect it to ground at the GMA end.
The pre-wired LEMO socket is pretty much sealed up with heat shrink and has a bunch of wire tails coming out of one end, so you don't have access to the terminals at the socket, only those wires that come out of the end.
This thread might help https://vansairforce.net/community/showthread.php?t=199500
The pre-wired LEMO socket is pretty much sealed up with heat shrink and has a bunch of wire tails coming out of one end, so you don't have access to the terminals at the socket, only those wires that come out of the end.
This thread might help https://vansairforce.net/community/showthread.php?t=199500
