Maxim Integrated Products, now part of Analog Devices, developed the MAX232 in 1987 as an integrated circuit (IC), to convert signals from TIA-232 serial ports to signals compatible with digital logic. More specifically, it converts RX and TX signals (which may reach up to 25 V) to the lower 5 volts used by digital logic; also providing two drivers and receivers connected to two pairs of RS-232 signals; however DTR, DSR, and DCD signals cannot be connected due to either PC serial port communication or special cables making these unnecessary.
In this How-To, we will use a MAX232 to connect our microcontroller to a PC and control LEDs, fans, relays and solenoids through serial port or USB to serial adapter of PC. This enables our microcontroller to serve as “brains” of our project while giving access to its full array of features.