Serial interface
Serial interface, referred to as serial port, also known as COM interface, is an extended interface using serial communication protocol. The serial port appeared around 1980, with a data transmission rate of 115kbps to 230kbps. The serial port is generally used to connect mice, external modems, old cameras, writing pads and other devices. Currently, some new motherboards have begun to cancel this interface.
Parallel interface
Parallel interface, referred to as parallel port, also known as LPT interface, is an extended interface using parallel communication protocol. The data transfer rate of the parallel port is 8 times faster than the serial port. The data transfer rate of the standard parallel port is 1Mbps. It is generally used to connect printers, scanners, etc. Therefore, the parallel port is also called the printing port.
The keyboard uses a PS2 interface, and now many use a USB port. The monitor has 15-pin D-sub and DVI interfaces