Why is the USB transmission speed so fast nowadays and what is its principle? The traditional serial port transfer speed is very slow, why there are many devices continue to use?

USB, is the English Universal Serial BUS (Universal Serial Bus) abbreviation, and its Chinese abbreviation for "through the serial line, is an external bus standard, used to standardize the computer and external devices connected and communication.

Previously, the USB1.1 pin, the speed is is 12 Mbps, the current mainstream is the USB2.0 standard, the highest speed is 480 Mbps. USB3.0 has also been formed, began to gradually promote the claim that the fastest to reach 5 Gbps.

Serial port is called the serial interface, also known as the serial communications interface, according to the electrical standards and protocols to include RS The RS-232-C, RS-422 and RS-485 standards specify only the electrical characteristics of the interface, not the connectors, cables or protocols.

Although the serial port transmission is slow, but in the control of data transmission does not require high speed, but rather the stability and security requirements (does not involve any standard network protocols), there is a simple and efficient developable.

Of course, this is a process, may be in the future with the gradual unification of control protocols and IP, the serial port will gradually be replaced by new technologies.