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# Modules
Tessel has two module ports, labeled A and B.
In the examples below, port "A" is always specified. But as long as you change the port in the code, you can plug your module into either of the ports.
It's best to unplug Tessel from power while plugging in modules.
At the bottom of this page are walkthroughs for the connection and installation of each module.
Modules should be plugged in so that all of the electrical components are on the top and the big hexagon is face down:
