Monday, November 20, 2000		On Hardware

USB — port attached to motherboard

THE USB or the Universal Serial Bus port is one such thing that is still a mystery for a majority of computer users. It is basically a port attached with the motherboard and has compatibility with almost all hardware gadgets.

Normally these days all computers come equipped with USB ports, though it is sometimes missing in the assembled PCs, despite the fact that their motherboards have support for the USB ports. However, these are useful and are, in fact, a prominent component of the computer. These ports are so useful that one can literally attach any peripheral— mouse, printers or a modem— effortlessly. One thing about the USB port is that these are the easiest to use and connect in comparison to the serial ports or parallel port. Moreover these ports also solve the problems of serial ports and parallel ports, as they are universal.

With so many hardware gadgets available today, like printers, scanners, modem, joystick, mouse, digital cameras and zip drives, the combination of 1 parallel and 2 serial ports, which is a part of the standard equipment in all hardware is grossly insufficient as the user has to take out some hardware gadgets to attach others to computer.

Thus, there was a need for some other ports that could provide high-speed connection with hardware gadget and does not differentiate the gadgets in parallel port and serial port. So, USB ports were added to the computer for finding a solution to this problem. A Universal Serial Bus gives a single, standardised, easy-to-use way to connect up to 127 devices to a computer. This may surprise as normally a computer comes with two USB ports. However, the user can utilise USB hubs, which can connect the above-mentioned number of items to computer and best of all they can run simultaneously too.

Normally the USB hubs come with 4 connectors but you can connect many USB hubs and so you can add peripherals. Each device can consume up to a maximum of 6 megabits per second of bandwidth, which is fast enough for a vast majority of peripheral devices that most persons want to connect to their machines. Since now all hardware peripherals come with the USB sockets, thus any peripheral can be connected to the computer. By using a USB port you can also have small network connections basically meant for small office and home purposes using hardware like Intel’s AnyPoint home network. Thus, like the direct cable networking, which is being done between serial-to-serial port or parallel to parallel port, the USB ports can also support networking features. Some other prominent features of USB port are as follows:

Using a USB port the computer acts as a host and has the maximum bus speed of 12 megabits per second. Also, from the USB port low-power devices e.g. mouse digital cameras can draw their power directly from the bus. However, some devices like printers have their own power supplies and draws minimal power from the bus. Hubs can also have their own power supplies to provide power to devices connected to the hub. Another feature of the USB port is that an individual USB cables can run up to 5 meters and with hubs, devices can stretch as much as 30 meters away from the host, which is more than enough for small offices.

As far as connecting the hardware device using the USB port is concerned, the procedure is similar to the serial or parallel port. For connecting a USB device to a computer, one must find the USB connector on the back of the machine and plug the USB connector to it. One can distinguish the USB socket easily as the rectangular socket is a typical USB socket on the back of the computer. Once you connect the hardware device to the USB port, it is ready for use, If it is a new device, then the operating system will auto-detect and ask for the driver disk as it is being done for connecting device to the normal serial and parallel port.

However, if the device has already been installed, the computer activates it and starts talking to it. So, here you can see the difference — as in case of USB ports you are not required to restart the computer for using the hardware. Similar to connecting, the device connected to the USB port can also be disconnected almost instantly. Like the serial port or the parallel port cable, the USB port also uses standard cable and is characterised by the standard A and B connectors to avoid confusion. "A" connectors head "upstream" toward the computer, while "B" connectors head "downstream" and connect to individual devices. By using different connectors on the upstream and downstream end, it is impossible to ever get confused — if you connect any USB cable’s B connector into a device, you know that it will work. Similarly, you can plug any "A" connector into any "A" socket and start using the hardware.

— VV