Why do you say that the two interfaces are very old, and many system and peripheral hardware update speeds lag behind the motherboard update speed, resulting in the purchase or installation is "toss" is not small, so this article calls these two interfaces For the edge interface. [COM port] COM port (cluster communication port) is the serial communication port, used to refer to the serial port (be careful not to be confused with the interface of the serial hard disk that everyone is used to call now). Usually also called RS-232 interface. In fact, there is a difference between the two. RS-232 is a serial communication standard, and the COM port is a specific implementation of RS-232. The computer is generally a 9-pin serial port, and is a male (pin), the female is a female (pinhole), arranged in two rows. Its peripheral shape is similar to the VGA interface. Motherboards on the market today rarely have such interfaces, but many peripherals still require this interface. Motherboards such as the popular low-end H81 chipset motherboards on the market, some have COM interfaces on the back, although some have no back, but there will be a socket in the board, you need to lead to the back of the chassis. Peripheral devices such as the PC control port of the PBX, the parking card PC control port, and some old fingerprint attendance machines. If there is no such interface on the computer, there will be some adapter cards/wires on the market, such as USB to COM, PCI to COM, PCI-E x1 to COM, but there is a high probability of compatibility problems after the transfer. The interface that is transferred out has the male and female points, and the male head that needs to be consistent with the computer can be mistaken. [LPT port] LPT port, usually connected to the printer, is often referred to as the printer port, also known as the parallel port (not to be confused with the old parallel port hard disk interface). The computer usually has 25 pins, arranged in two rows, the female end of the T-shaped periphery, and the male is on the line. The printer is different at one end. This interface has basically been replaced by a USB interface. There are very few motherboards on the market with this interface. Older printers use this type of interface. So be careful when working with your computer. If there is no LPT port on the computer, there is a USB to LPT port wire on the market, the price is high, and there is a high probability of compatibility problems. The patch cord has the male and female heads, and it needs to be the same as the female head of the computer. Don't make a mistake. Of course, there is also a direct conversion to the printer connector. [Small knowledge: serial port, parallel port] The so-called serial port means that the data is transmitted in serial mode, that is, one bit by one transmission, generally one-pin reading and one-pin writing. For example, the COM port and the SATA port belong to the serial port. The parallel port is a plurality of pins that transmit multiple bits at the same time, such as LPT port and IDE port. This article comes from [system home] www.xp85.com Related articles recommended: 1. Do you know the display output interface on the computer 2. Teach you to know the internal interface of the notebook 3. How to do the computer network cable interface light is not bright