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Please contact us. We just sent you an email to confirm your email address. Once you confirm your address, you will begin to receive the newsletter. Serial Port. Definitions by TechTerms. Tech Factor? A port is a connection point or an interface where you plug in an external device such as a printer, scanner, keyboard, and mouse, among others. This allows instructions and data to flow between the computer and the attached device. Many computer connectors are polarized to ensure they are plugged in the right way.
Note that some of the types of computer ports you are going to encounter here are obsolete. It is well understood that technology keeps changing now and then. It is always important to know what kind of technology was there before the current one.
It is for connecting older AT keyboard types. The 6-pin Mini-DIN was first used on laptops. It is used to connect a computer mouse or keyboard. The PS2 connectors are colour-coded. The purple connector is for the keyboard while the green one is for the mouse. To plug in a keyboard or mouse cable, first match the cable notches to the connector.
Rotate the cable until the connector keys match up. Then push the cable into the connector. These ports are rarely used nowadays as they have been replaced by USB ports.
A parallel port is used to connect external devices such as scanners and printers. The older type was Centronics 36 Pin Port before being replaced by the DB port with a parallel interface. The pin port is sometimes referred to as a printer port. These ports have been replaced by the USB port. It is an asynchronous port on the computer used to connect a serial device to the computer and capable of transmitting one bit at a time. 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. USB uses four wires. Two wires are used to provide power, and data is transferred over a twisted pair of wires. USB ports are shown in Figure 8. Figure 8: USB Ports. USB has several advantages over its serial predecessors, including:. USB power was designed only to be used with low-power devices, such as mice or keyboards.
For example, printers and external hard drives must provide their own power source and draw little power from the USB bus. USB devices are hot-swappable , meaning that one can connect them and disconnect them at any time without restarting the computer. When the host computer enters a power-saving mode, the host can put connected USB devices into sleep mode to save power. Windows 95 and Windows NT 4. To avoid confusion and prevent electrical overloads, the USB standard specifies an A connector and a B connector.
Only an A-type port provides power. The A connector , shown in Figure 9 , is a flat connector that sends the data upstream. The A connector is found on the back of the computer and the B connector is found on the external device. USB has iterated through several versions over the years.
The original USB 1. USB 1. USB 2. However, USB 1. USB 3. It is important to be familiar with the acceptable range of cable lengths for USB. High-speed devices support maximum cable lengths of 5 meters, while low-speed devices support a maximum cable length of 3 meters. These lengths can be extended with the use of powered hubs. USB connections are used for any number of devices, including cameras, scanners, and barcode readers.
It was intended as a high-speed, bidirectional Mbps serial transfer technology, for scanners, camcorders, and digital cameras. PC users, of course, wanted to take advantage of the higher speed of FireWire, so manufacturers created a special adapter card that would plug into the PCI slots common to PCs.
Another advantage of FireWire is that it forms a peer-to-peer connection, meaning that any two FireWire devices can be plugged together directly and communicate with each other without a computer in the middle. FireWire slots are now included on most motherboards. There are 4-conductor and 6-conductor FireWire implementations.
A 6-conductor FireWire device can draw power through the cable just as in the case of USB; two power conductors are included, supplying a maximum of 30 volts and 1. Low power consumption devices, such as digital cameras, can draw power from a 6-conductor FireWire port; high power consumption devices, such as external hard drives, may require a separate AC power source.
A FireWire cable has either two or three pairs of twisted wires that carry data. Figure 10 displays 4-conductor and 6-conductor FireWire connectors. Figure 11 displays 6-pin FireWire ports.
The recommended maximum length for a FireWire cable is 4. Figure 6-Pin FireWire Ports.
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