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相关文章：计算机英语之影响数据传送的主要因素（译文）
Main Factors Affecting Data Transmission
There are several factors that affect data transmission. They include speed or bandwidth, serial or parallel transmission, direction of data flow, modes of transmission data, and protocols.
Bandwidth The different communications channels have different data transmission speeds. This bit-per-second transmission capability of a channel is called its bandwidth. Bandwidth may be of three types: voiceband, medium band, and broadband. Voiceband is the bandwidth of a standard telephone line and used often for microcomputer transmission, the bps is 300-9600. Medium band is the bandwidth of special liased lines used mainly with minicomputers and mainframe computers, the bps is 56,000/264 million. Broadband is the bandwidth that includes microwave, satellite, coaxial cable, and fiber-optic channels. It is used for very high-speed computers whose processors communicate directly with each other. It is in the range of 56,000/30 billion bps.
Serial or Parallel Transmission Data travels in two ways: serially and in parallel. In serial data transmission, bits flow in a serial or continuous stream, like cars crossing a one-lane bridge. Each bit travels on its own communications line. Serial transmission is the way most data is sent over telephones lines. Thus, the plug-in board making up the serial connector in a microcomputer's modem is usually called a serial port. More technical names for the serial port are RS-232C connector and asynchronous communications port. With parallel data transmission, bits flow through separate lines simultaneously. In other words, they resemble cars moving together at the same speed on a multilane freeway. Parallel transmission is typically limited to communications over short distances and is not used over telephone lines. It is, however, a standard methods of sending data from a computer's CPU to a printer.
相关文章：计算机英语之影响数据传送的主要因素（译文）
Main Factors Affecting Data Transmission
There are several factors that affect data transmission. They include speed or bandwidth, serial or parallel transmission, direction of data flow, modes of transmission data, and protocols.
Bandwidth The different communications channels have different data transmission speeds. This bit-per-second transmission capability of a channel is called its bandwidth. Bandwidth may be of three types: voiceband, medium band, and broadband. Voiceband is the bandwidth of a standard telephone line and used often for microcomputer transmission, the bps is 300-9600. Medium band is the bandwidth of special liased lines used mainly with minicomputers and mainframe computers, the bps is 56,000/264 million. Broadband is the bandwidth that includes microwave, satellite, coaxial cable, and fiber-optic channels. It is used for very high-speed computers whose processors communicate directly with each other. It is in the range of 56,000/30 billion bps.
Serial or Parallel Transmission Data travels in two ways: serially and in parallel. In serial data transmission, bits flow in a serial or continuous stream, like cars crossing a one-lane bridge. Each bit travels on its own communications line. Serial transmission is the way most data is sent over telephones lines. Thus, the plug-in board making up the serial connector in a microcomputer's modem is usually called a serial port. More technical names for the serial port are RS-232C connector and asynchronous communications port. With parallel data transmission, bits flow through separate lines simultaneously. In other words, they resemble cars moving together at the same speed on a multilane freeway. Parallel transmission is typically limited to communications over short distances and is not used over telephone lines. It is, however, a standard methods of sending data from a computer's CPU to a printer.