USB Information | Tech Info Home Page |
A new computer hardware technology which surfaced in 1996 geared towards replacing the serial ports, parallel ports and other I/O devices. Initially scheduled to debut late 1996 with products slowly coming out in 1997.
A USB port is a small rectangular connector on the back of a computer. A cable connects from this connector to the USB device. Hubs which can connect up to 4 devices can also be used to add more peripherals. The PC USB port and hubs use a Type A rectangular socket.
USB hardware include:
- Digital Cameras
Developed by Microsoft®, Intel®, Compaq® and others. Initial designs called for PnP plug-and-play support (allowing the detection of a new piece of equipment), ability to connect almost any peripheral ( limit of 127) and ability to hot swap ( disconnect and connect ) with the computer running.
Windows 95 does not support USB. The OEM OSR2 version (windows 95b) does have USB support if you use special software.
Windows 98, 98se, ME and Windows 2000 support USB (version 1.1) automatically.
USB detects when a device is connected or disconnected to the standardized USB connector, and automatically determines what drivers or resources are needed. The required resources are allocated automatically with no user intervention. The process can be performed with power on. Windows might not detect a device if it draws too much power.
The USB peripherals can provide an extra connector which can be used to connect other peripherals or the new peripherals can be connected to a centralized expansion hub if one is provided.
An example would be a USB keyboard that has a connector on the back so a peripheral can be added. The maximum distance for each peripheral is 5 meters. Additionally USB provides +5 volt power thus eliminating the need for the peripherals to have an outside power source.
Newer Motherboards have a USB Plug which you can use to add an external USB connector to your computer.
- High-speed (480Mbps) - only works with USB revision 2.0
- Full-speed (12 Mbps) - works with revision 1.1 (revision 2.0 cards can also use the 12Mbps and 1.5Mbps speeds since they are backward compatible)
- Low-speed (1.5 Mbps) - works with revision 1.1 (revision 2.0 cards can also use the 12Mbps and 1.5Mbps speeds since they are backward compatible)
USB Connectors -
- The back of the computer has a Type A Female connector
- The back of a peripheral device has a Type B Female connector
- To connect a standard USB peripheral to the connector on the back of a computer you use a cable that has a Type A Male connector on one end and a Type B Male connector at the other end.
- To connect a USB Hub to the back of a computer you use a cable that has a Type A Male connector on one end and a Type B Male connector at the other end (the same cable is used to connect a peripheral to a computer as to connect a hub to a computer.)
How to tell if a USB connection is male of female -
Type A Female connector
Type A Male connector
USB specifications outlined
The 82930A is the first USB-compliant peripheral controller chip.
How to ...
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