I bought an Ethernet Shield R3 for my Arduino Uno R2, but since R3 has extra pins it does not fit. Can I use the shield? Should I cut off the extra pins. What do I need to do to make it work?

  • @AsheeshR These extra pins get in the way when putting the shield on the Arduino. If I cut them off it would fit. Should I cut them off?
    – tstew
    Feb 12, 2014 at 4:23
  • Which pins are interfering? I dont have the shield, but from what I can make out, the extra pins on the shield do not seem to be areas where there would be any conflict.
    – asheeshr
    Feb 12, 2014 at 4:35

2 Answers 2


The only issue that may create an incompatibility seems to be the IOREF pin next the 5V output pin which is extra on Revision 3 but not in Revision 2.

However, I just had a look at the board schematics and the shield does not use IOREF.

Pin 2 is extending IOREF

So, the shield should work correctly with the Uno Revision 2. As far as the extra pins are concerned, I would recommend not damaging them in any way. If you absolutely need to, then just try to bend them outwards very carefully.


The extra pins do not matter. Just leave them. If you really want, cut them off, but this will remove some compatibility with other products.

They should hang off the ends of the headers closest to the power/USB end of the board.

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