Zeroplus Arduino starter kit with Logic Analyzer Manual page 47

REAL LIFE APPLICATIONS
• The serial port has slowly disappeared from consumer electronics, but
is still in use in industrial applications. Also, most microcontrollers
such as the one embedded on your Arduino board is equipped with a
UART.
• Pictured below, the RS-232 connector was widely used before USB
became a standard.
DTR
4
GND
5
RI
9
CTS
8
TXD
3
RXD
2
DCD
1
DSR
6
RTS
7
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