How to connect the reader to the computer

The connection methods of RFID reader and computer are usually: serial port RS-232, RS-485, Wiegand26 \ 34 \ 42, RJ45, WIFI, etc.

The UHF readers currently popular on the market usually provide a serial communication connection, and the serial port is also the most important method for most hardware to communicate with the computer. So let us first understand what is a serial port?

Serial port is short for serial communication interface (Serial Interface), also known as COM port. Its characteristic is that the communication line is simple, as long as a pair of transmission lines can realize two-way communication, and can use the telephone line, thereby greatly reducing the cost, especially suitable for long-distance communication, but the transmission speed is slow. The communication method in which the data of each bit of a message is transmitted bit by bit in sequence is called serial communication. The characteristics of serial communication are: data bit transmission, the transmission is carried out in bit order, at least only one transmission line can be completed; low cost but slow transmission speed. The distance of serial communication can be from several meters to several kilometers; according to the direction of information transmission,

Serial communication can be further divided into simplex, half-duplex and full-duplex.

The initial appearance of the serial port is to achieve the purpose of connecting computer peripherals. The initial serial port is generally used to connect devices such as a mouse and an external modem, as well as an old-style camera and a tablet. The serial port can also be used due to the interconnection and data transmission between two computers (or devices). Because the serial port (COM) does not support hot plugging and the transmission rate is low, some new motherboards and most portable computers have begun to cancel the interface. At present, the serial port is mostly used in industrial control and measurement equipment and some communication equipment. Serial interfaces are roughly divided into RS-232, RS-422, RS485, etc. according to electrical standards and protocols. Among them, RS-232 is also called standard serial port, which is the most commonly used serial communication interface. It adopts unbalanced transmission mode, so-called single-ended communication. The maximum transmission distance is about 15 meters, and the maximum rate is 20kb / s. RS-232 is designed for point-to-point (that is, using only a pair of receiving and sending equipment) communication, and its driver load is 3 ~ 7kΩ. Therefore, RS-232 is suitable for communication between local devices. In the connection of the reader device introduced later, the standard 9-pin RS232 interface is also mainly used. 9-pin interface pin of RS232 serial data cable