We have several of the 7937 Conference phones with the external mic kit.
For some reason they don't work when you plug them in.
Somehow, I got one of the phones to work with them, but I still don't know what I did. Several resets- unplugging it and they just started working.
But another I can't seem to make them work.
These are all new in the box. I don't see any settings in the CUCM to 'enable' external mics or anthing...
Ok- I feel sort of stupid.
Turns out that even though you can plug in the external mics either way- they must be the same on both ends.
After looking at the ends I saw how the pins where, and that they must be oriented the same way.
Strange the book doesn't say anything about it and there are no markings on the cables.
Oh well, thought I'd put up the solution so if someone else is as dense as me it will save them some time.
Awesome info! No markings on either end to indicate there is any difference in the cables to be plugged into the phone vs. mics, so the difference must internal. Leave it to Cisco! You should label each side of cables indicating what's its plugged into in case others on your IT team install hardware.