What are the external interfaces of the computer?
Serial interface is abbreviated as serial port, also known as serial communication interface or serial communication interface (usually refers to the COM interface, that is, the one that looks like the VGA interface), which is an expansion interface using serial communication. According to electrical standards and protocols, it includes RS-232-C, RS-422, RS485, USB, etc. The RS-232-C, RS-422 and RS-485 standards only stipulate the electrical characteristics of the interface, and do not involve connectors, cables or protocols. Now there is no serial interface on the home computer, but some industrial computers will also be equipped with a serial interface.
Of course, strictly speaking, USB is also a kind of serial bus, and its scientific name is universal serial bus. USB is currently the most widely used interface specification on computers. It is a new peripheral interface standard initiated by several major manufacturers such as Intel, Microsoft, Compaq, IBM, NEC, and Northern Telcom. For details, please check my previous article.
2. Parallel interface
Parallel interface is abbreviated as parallel port, which refers to the interface standard that uses parallel transmission to transmit data. There are dozens of types from the simplest parallel data register or special interface integrated circuit chip such as 8255, 6820, etc., to the more complicated SCSI or IDE parallel interface.
In our daily life, many people also call it the printer port. The parallel port uses a 25-pin D-shaped connector. The so-called "parallel" refers to the simultaneous transmission of 8-bit data, so that the data transmission rate will be greatly improved, but it should be noted that the length of the parallel transmission line is limited, not too long, otherwise the interference will increase , The data will be more wrong.
Of course, parallel port is not only used in printers in the past, there are many other uses, such as ZipDrive, scanners, some early sound cards and some old cameras, as well as EPROM programmers, simulators and other devices are used in parallel Interface.
Like the COM port, with the widespread popularity of USB devices, the living space of the parallel port is getting smaller and smaller, but it occupies a very large part of the I/O part. Until the end, all the companies gave up the parallel port and added more. Multiple USB ports.
3, IEEE1349 interface
The IEEE1394 interface, commonly known as the FireWire interface, is mainly used for video collection. It was once seen on the Intel high-end motherboard and digital video camera (DV). It is a high-speed transmission interface developed by the development alliance led by Apple. The data transmission rate is generally 800Mbps. . FireWire is a trademark of Apple Inc. Sony products call this interface iLink.
In the era of USB1.0, its speed and stability are much higher than that of USB1.0, which is welcomed by various professional devices. In the era of USB2.0, although its speed still does not fall, and the owner's USB interface does not have Transmission stability, but due to the wide application of USB, it is rapidly popularized. In the USB3.0 era, the speed of the FireWire interface has been far behind, and due to its excessive consumption of CPU resources and the high cost of its interface, it has been quickly eliminated. Now even iMAC has canceled this interface, we can only see this interface on some professional devices.
4. eSATA interface
ESATA is a data interface. When it comes to the interface of external storage devices (such as mobile hard drives), everyone will invariably think of USB or IEEE1394. Although the data transmission rate of these two interfaces has reached 480Mbps/400Mbps, but they can not really realize the maximum potential of devices such as hard disks. This is because the USB2.0 or IEEE1394 mobile hard disk must use a bridge chip to achieve the interface conversion, this connection will undoubtedly greatly affect the performance of the device.
We mentioned this interface before. The eSATA interface is undoubtedly a short-lived interface, which was eliminated soon after it appeared. eSATA is actually an extension of SATA2. It can be understood as the SATA2 power generation. eSATA can only require a wire to allow users to connect the hard disk from outside the chassis. The speed is much higher than that of the FireWire interface and USB2.0 at that time, and supports hot swap . But this interface has gone from popular to disappear in just a few years. The reason for its disappearance can only be said to be out of date, and encountered the epoch-making USB3.0 interface soon after its appearance. Next came SATA3, which made its advantages disappear in a very short time, which made its status even worse than a USB hard disk box in a short time.
If you want to know more, our website has product specifications for external interfaces of the computer, you can go to ALLICDATA ELECTRONICS LIMITED to get more information