I received a Adafruit Feather 32u4 FONA as a gift and have read the great, comprehensive document Adafruit put have put together surrounding pinouts, examples etc for the board. I am having issue understanding the section on the KEY pin, I understand that it is used to put the cellular module to sleep, but in order to do this it is mentioned to “cut the trace and wire it to a micro controller pin”. Does this mean that in order to utilize the on/off functionality of the SIM module I have to slightly butcher my new shiny board instead of using the pin directly?

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    When you have to cut a track there is normally an exposed area between two pads, clearly marked as the bit of track to cut. You are right with what it means, because doing this saves the manufacturer the few cents adding a jumper would have cost :) Jun 29, 2018 at 12:17

1 Answer 1


Yes, you will need to physically cut the trace to use the on/off feature. This is common on development boards. It could be done with a jumper but that would add cost and/or require a larger board.

You will see on the back of the board there are 2 large pads connected by a thin trace. You can use an exacto knife to cut the trace. To repair the cut you use a blob of solder to bridge the gap between the pads.


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