Is the EThernet a add on or can it be bought built in?

Other Hardware 3rd Party Boards
1

I was searching the arduino online store and was wondering is the ethernet shield the only piece you need or do you need the UNO board to use the piece of hardware. Also, are the models listed as UNO/Ethernet a UNO with a built in Shield or is it integrated into the system or is it only a combo?

2

You can use an Arduino UNO ($30) + Ethernet Shield ($45) or and Arduino Ethernet ($65).

3

There's a subtle difference between using the shield and having the ethernet chip built-in. The Arduino Ethernet does not have an on-board USB to Serial chip and it is not designed to be programmed over Ethernet.

  1. Arduino Uno + Ethernet Shield = Communicate with Ethernet, program with USB.

  2. Arduino Ethernet = Communicate with Ethernet, program with FTDI (or similar USB to Serial) Cable.