The physical layer

Finally, we've arrived at the bottom of the stack, with the simplest layer to understand. The physical layer encapsulates the entities that are responsible for transmitting raw, unstructured data from one node in the network to another. This is the layer responsible for sending electrical signals that correspond to the strings of bits in a data packet. It encapsulates the devices responsible for modulating voltage, timing signals, and timing the frequency of wireless transmitters and receivers. Entities on this layer are explicitly outside of the scope of this book, but are an interesting concern regardless.