Hardware Reference
In-Depth Information
needs to connect to an RS-232 compatible device. Luckily, Arduinos use USB
communications, so an adapter is not required.
Serial
Parallel
Figure 5-1:
Serial versus parallel
Serial ports are extremely simple. This simplicity is one reason why they are
used so often. Data is sent on one wire, the transmit wire (TX), and received on
another, the receive wire (RX). On the other side of the cable, it is connected to
another computer with a TX pin and an RX pin. Inside the cable itself, the TX
and RX wires are inverted. The TX pin on one side is connected to the RX pin
on the other side. This is illustrated in Figure 5-2.
TX
TX
RX
Figure 5-2:
Transmit and receive wires
RX
With all the technological advances made over the years, you could ask the
question: Why do systems still use RS-232? There are several reasons. First, it
is a proven technology in that it has been used reliably for decades. Second,
there are a large amount of cheap electronic components that communicate via
RS-232. They are easy to use, requiring only a few lines of code to implement.
Third there is the cable distance. Although not necessarily a big advantage for
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