Advantages of usb over serial and parallel ports

Parallel communication is and always has been widely used within integrated circuits, in peripheral buses, and in memory devices such as RAM.

Computer system buses, on the other hand, have evolved over time: parallel communication was commonly used in earlier system buses, whereas serial communications are prevalent in modern computers.

Before the development of high-speed serial technologies, the choice of parallel links over serial links was driven by these factors:. The decreasing cost and better performance of integrated circuits has led to serial links being used in favor of parallel links; for example, IEEE printer ports vs.

On the other hand, there has been a resurgence of parallel data links in RF communication. Each such group of bits is called a 'symbol'. Such techniques can be extended to send an entire byte at once QAM. The USB port is not a passive port like the serial port or the parallel port. It is always subject to the use of a specific driver for the device used. A serial-in, parallel-out shift register is similar to the serial-in, serial-out shift register in that it shifts data into internal storage elements and shifts data out at the serial-out, data-out, pin.

It is different in that it makes all the internal stages available as outputs. Therefore, a. New posts Latest activity. Thread starter robinhung Start date Feb 23, Sidebar Sidebar. Forums Hardware and Technology Computer Building. JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding. Previous Next. Aug 7, 0 0.

I've got a new laser printer Samsung ML TimeKeeper Diamond Member. Nov 3, 4, 0 0. BTW, great choice for your printer! Feb 22, 0 0. Jun 30, 5, 8 So speed isn't an issue.

ALstonLoong Golden Member. Oct 24, 1, 0 0. The most significant issue is that the port is non-standard. And good luck trying to use the parallel port on your laptop computer.

Most manufacturers have different implementations of the parallel port. On most computers there is usually only one parallel port available which can cause many headaches if that port needs to be shared with a printer or scanner. Total Phase. Register Login. Serial connections are characterized by the use of a DB-9 male or a DB male connector. DB references the D shape and the shell size B , and the number represents the number of pins in the connector.

Figure 3 displays a DB-9 connector. Figure 3: DB-9 Serial Port. Serial ports are also known as communication or COM ports. They are bidirectional , meaning data can flow in both directions, either sending or receiving data. Serial ports use various pins to send and receive data. Using different pins allows for full-duplex communication, in which information can travel in both directions at once. Serial ports are also referred to as RS ports ; this is because RS is a particular standard for serial communication that used to be integrated into almost all computers.

The recommended maximum length of an RS cable is 15 meters. USB ports will be described in detail later in this lesson. DIN-5 Connector. Older AT style motherboards had only one connection port built-in. Figure 4 shows a DIN-5 connector. The purple connector is always for the keyboard and the green connector is always for the mouse.

The keyboard and mouse are not interchangeable. Parallel ports on motherboards are used for printers, scanners, and other devices that need high throughput. Many motherboards no longer include parallel ports, because modern peripherals normally use USB connections. Parallel ports use a DB female connector which transfers two bytes of information at a time over 16 wires, with the remaining 9 wires used for control signaling.

Since there are both serial and parallel port implementations of DB, it is important to be able to tell them apart. When looking at the computer, the serial port is always a male connector, and the parallel port is always a female connector. Parallel ports are also known as LPT ports. There can be up to three of these ports on a motherboard, but nowadays usually zero or one.

This port is bidirectional, and the transmission mode for this port can be set in the BIOS. The IEEE standard specifies parallel communication between a computer and a connected printer via a parallel cable. As described above, the port on the computer is a DB port, referred to in the standard as Type A.

Figure 6 displays a DB parallel port. The printer port which connects by a cable to the parallel port of a computer is a pin Centronics port , referred to in the standard as Type B. Figure 6: DB Parallel Port. Figure 7 displays a Centronics connector. The recommended maximum length of a parallel cable is 4. Figure 7: Centronics Connector.