At present, there is a serial hard disk SA Han A interface, and the parallel port is an ide interface. At present, serial port has replaced parallel port.
Printer serial port usually means that 1 uses 9-pin D connector, also known as RS-232 interface, and parallel port uses 25-pin D connector. At present, parallel port is widely used because of its high transmission speed.
The serial port and serial port of the mouse are the same as the 5-pin rs-232 interface of the printer. As for parallel port, I know nothing about it and have never heard of it.
Question 2: What do serial port and parallel port mean? A serial port means:
Serial interface refers to the sequential transmission of data bit by bit, and its characteristics are as follows
serial interface
However, the communication line is simple, and two-way communication can be realized only by a pair of transmission lines (telephone lines can be directly used as transmission lines), which greatly reduces the cost and is especially suitable for long-distance communication, but the transmission speed is slow. The communication mode in which each bit of information is transmitted bit by bit in sequence is called serial communication. The characteristics of serial communication are: the transmission of data bits is carried out in bit order, and at least one transmission line is needed; Low cost but slow transmission speed. The distance of serial communication can be from several meters to several kilometers; According to the transmission direction of information, serial communication can be further divided into simplex, half-duplex and full-duplex.
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Parallel port indicates:
The parallel interface is generally called Centronics interface, also known as IEEE 1284, which was first formulated by Centronics Data Computer Company in the mid-1960s. Centronics was originally designed as a parallel interface for dot matrix line printers, and was adopted by IBM in 198 1, and later became the standard configuration of IBM PC computers. It adopted TTL level, which had become the mainstream at that time. At that time, it transmitted 1 byte (8 bits) data in parallel in one direction, which was faster than the serial interface at that time (only 1 bit could be transmitted at that time), and it was widely used and became the interface standard of printers. 199 1 year, Lexmark, IBM, Texas Instruments and other companies compete with other interfaces, expand the application scope, improve the Centronics interface, and realize higher-speed two-way communication to connect computer peripherals (referred to as peripherals) such as disk drives, tape drives, optical disk drives, and network devices. Finally, the IEEE 1284- 1994 standard was formed, which is called the standard signaling method of bidirectional parallel peripheral interface of personal computer, and the data rate was increased from 10KB/s to 2MB/s( 16Mbit/s). But in fact, this two-way parallel communication has not been widely used. Parallel interfaces are still mainly used for printers and plotters, and there are few other devices. This kind of interface is generally called print interface or LPT interface.
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Question 3: What is a serial port and a parallel port? serial interface
Serial interface, referred to as serial port, is an extended interface using serial communication protocol. The serial port appears around 1980, and the data transmission rate is115 bps to 230 kbps. Serial port is generally used to connect mouse and external modem, old camera and tablet. At present, some new motherboards have begun to cancel this interface.
parallel interface
Parallel interface, LPT interface for short, is an extended interface using parallel communication protocol. The data transmission rate of parallel port is 8 times faster than that of serial port, and the data transmission rate of standard parallel port is 1Mbps, which is generally used to connect printers and scanners. So the parallel port is also called the printing port.
In addition, both serial port and parallel port can be interconnected by direct cable connection, in which data can only be transmitted at low speed. The function and structure of serial port and parallel port of PC have not changed for many years. When using serial-parallel ports, in principle, each peripheral must insert an interface. If all interfaces are used, you can only add interfaces by adding cards. Serial port and parallel port are not only limited in speed, but also inconvenient to use, such as not supporting hot plug. With the popularization of USB interface, it is rarely used at present, and it will be eliminated with the promotion of BTX specification.
Question 4: What is a computer serial port? Serial port is the kind of hard disk with narrow data line (new technology)
Parallel port is the kind of line width (old technology)
Question 5: What is the main difference between serial port and parallel port? Serial interface refers to the sequential transmission of data bit by bit, which is characterized by simple communication lines, two-way communication as long as a pair of transmission lines can be realized, and telephone lines can be used, which greatly reduces the cost, and is especially suitable for long-distance communication, but the transmission speed is slow.
serial interface
The communication mode in which each bit of information is transmitted bit by bit in sequence is called serial communication. The characteristics of serial communication are: data bits are transmitted in bit order, and at least one transmission line is needed; Low cost but slow transmission speed. The distance of serial communication can be from several meters to several kilometers; According to the transmission direction of information, serial communication can be further divided into simplex, half-duplex and full-duplex.
Parallel interface refers to the interface standard that uses parallel transmission to transmit data. From the simplest parallel data registers or special interface integrated circuit chips such as 8255, 6820, etc. , to more complex SCSI or IDE parallel interfaces, there are dozens. The interface characteristics of parallel interface can be described from two aspects: 1, the width of data channel transmitted in parallel, also known as the number of bits transmitted by the interface; 2. Characteristics of additional interface control lines or interactive signals used to coordinate parallel data transmission.
The width of data can be from 1 to 128 bits or more, of which 8 bits are the most commonly used, and 8 data bits can be transmitted at a time through this interface. The most commonly used parallel interface in computer field is LPT interface.
Question 6: What are the differences and functions between parallel lines and serial lines? What is a serial communication interface? Data 1 bit 1 bit transmission such as RS232 RS485 RS422 USB.
Parallel port parallel communication interface, data 8-bit 8-bit transmission (or multiples of 8) LPT 1.
Question 7: What is a parallel interface and what is a serial interface? Which input and output devices belong to what? Parallel communication means that each digit of a character is transmitted by several lines at the same time, with high transmission speed and high information rate. But it uses more cables than serial communication, so it is often used in situations with short transmission distance (several meters to tens of meters) and high data transmission rate.
The interface to realize parallel communication is a parallel interface.
Parallel interfaces can be designed as input/output interfaces only, or as input and output interfaces. This can be achieved in two ways. One is to use two paths in the same interface, one for input and the other for output. The other uses the same bidirectional path, which is used as both input and output.
Interfaces connecting devices include PS/2, PATA, LPT, etc.
Serial communication refers to the sequential transmission of data bit by bit, and each bit of data occupies a fixed length of time. It only needs a few lines to exchange information between systems, especially for long-distance communication between computers and between computers and peripherals.
The interfaces for connecting devices are SATA, USB, etc.
Question 8: What do serial port and parallel port mean? What is the difference? In the past two years, the word that people have heard the most is probably serialization. From the development of technology, serial transmission mode completely replaces parallel transmission mode, USB replaces IEEE 1284, SATA replaces PATA and PCI Express replaces PCI. ...
In principle, the parallel transmission mode is actually superior to the serial transmission mode. Generally speaking, parallel drive is like a wide road with multiple lanes, and series drive is a country road where only one car can pass. Take the ancient and typical standard parallel port and serial port (commonly known as port) as an example. The bit width of the parallel interface is 8, and the data transmission rate is high. The serial port only has 1 bit, so the data transmission speed is low. During the time when the serial port transmits 1 bit, the parallel port can transmit one byte. When the parallel port completes the transmission task of the word "advanced", only the first letter "a" of the word is transmitted in the serial port.
The speed of figure 1:H6A-2- 1 TIF parallel interface is 8 times that of serial interface.
So, why is the current serial transmission better?
First of all, parallel transmission technology has encountered difficulties in development.
The bus and interface in the computer are the "arteries" for transmitting data between the host and external devices. With the continuous improvement of processor speed, the data transmission speed of bus and interface needs to be gradually improved, otherwise it will become the bottleneck of computer development.
Fig. 2 development of PC bus
Let's look at the bus first. The first PC in 198 1 adopted an open architecture marked by ISA bus. The data bus is 8 bits, and its working frequency is 8.33MHz, which was considered as "advanced technology" at that time, so ISA bus has another name "AT bus". By 286, the bit width of ISA has increased to 16 bits. In order to maintain compatibility with 8-bit ISA, the working frequency is still 8.33MHz. Although ISA bus only has a data transmission rate of 16MBps, it has been the fastest data channel between the motherboard and external devices until 386.
In the era of 486, two faster bus standards, PCI and VESA, appeared at the same time. They have the same bit width (32 bits), but the PCI bus can run asynchronously with the processor. When the frequency of the processor increases, the PCI bus frequency can still remain unchanged, and three frequencies can be selected: 25MHz, 30MHz and 33MHz. VESA bus works synchronously with the processor, so with the increase of processor frequency, the working frequency of peripheral devices of VESA bus type also increases, and its adaptability is poor, and it soon loses its competitiveness. PCI bus standard has become the king of PC bus in Pentium era, and all hard disk controllers, sound cards and network cards use PCI slots. On the other hand, graphics cards require higher data transmission speed, and special AGP appears.
Parallel data transmission technology has always been an important means to improve data transmission rate, but its further development has encountered obstacles. First of all, because the premise of parallel transmission mode is to spread the signal at the same time sequence and receive the signal at the same time sequence, if the clock frequency is excessively increased, it will be difficult to synchronize the data transmission time sequence with the clock. If the line length is slightly different, the data will be transmitted in a timing different from the clock. In addition, increasing the clock frequency is likely to cause mutual interference between signal lines, leading to transmission errors. Therefore, it is difficult to achieve high speed in parallel mode. From the point of view of manufacturing cost, increasing the bit width will undoubtedly lead to an increase in the number of wires on the motherboard and expansion board, and the cost will rise accordingly.
As for the external interface, we know that the speed of IEEE 1284 parallel port can reach 30.
0kBps, when transmitting graphics data, the compression technology can be improved to 2MBps, while the data transmission rate of RS-232C standard serial port is usually only 20kbps, and the data transmission rate of parallel port is undoubtedly better. Therefore, for more than ten years, parallel port has been the preferred connection method for printers. For a stylus printer that only transmits text, > >
Question 9: What is the meaning of serial parallel port in computer? Serial interface serial interface, referred to as serial port, is an extended interface using serial communication protocol. The serial port appears around 1980, and the data transmission rate is115 kbps to 230 kbps. Serial port is generally used to connect mouse and external modem, old camera and tablet. At present, some new motherboards have begun to cancel this interface. Parallel interface, referred to as parallel port for short, is an LPT interface and an extended interface using parallel communication protocol. The data transmission rate of parallel port is 8 times faster than that of serial port, and the data transmission rate of standard parallel port is 1Mbps, which is generally used to connect printers and scanners. So the parallel port is also called the printing port. In addition, both serial port and parallel port can be interconnected by direct cable connection, in which data can only be transmitted at low speed. The function and structure of serial port and parallel port of PC have not changed for many years. When using serial-parallel ports, in principle, each peripheral must insert an interface. If all interfaces are used, you can only add interfaces by adding cards. Serial port and parallel port are not only limited in speed, but also inconvenient to use, such as not supporting hot plug. With the popularization of USB interface, it is rarely used at present, and it will be eliminated with the promotion of BTX specification. Where there are serial ports and parallel ports on the computer, there should be: hard disk, motherboard, printer. Serial ports are generally used to connect some special external devices. Such as communication equipment. Parallel ports are usually used to connect printing devices. The serial port is relatively small, and there are prominent needles exposed. Parallel ports are generally larger than serial ports and are usually red. The serial port has two rows of holes, which are described as one channel, while the parallel port refers to eight channels, which can transmit 8 bits (one byte) of data at the same time. But the speed of parallel port is not fast, because 8-bit channels interfere with each other. Transmission is limited by speed. Moreover, when transmission errors occur, 8-bit data should be retransmitted at the same time. The serial port has no interference. Just resend one bit after transmission error. So fast is faster than parallel port. This is the importance people attach to the serial hard disk.