The Universal Serial Bus gives you a single, standardized, easy-to-use way to connect up to 127 devices to a computer....
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The 127 number is a theoretical number :) In practice it's a lot less! The devices you connect can even power through the USB port of your computer if they draw less than 500mA, which is half an Ampere (I). A good example is my little Canon scanner, it only has one cable which is used to power the scanner up and to transfer the data to the computer!
Currently there are two versions of the USB port, the initial version which is USB v1.1 and the newer version USB v2 which has hit the market since the end of 2001. Most people have computers and devices which use the first version, but all new computers will now come with USB v2. This new version of the USB port is backwards compatible with the older version and also a lot faster.
The table below compares the two USB ports so you can see the speed difference:
Keep in mind that when you're using a USB DCC cable, you won't get such great speeds, but somewhere around the 500 Kbps. This also depends on the type of CPU, O/S, the quality of the cable and electronic components and protocols running on your system. Another thing which you should keep in mind is the Windows Operating System that supports the USB port:
The USB cable
This is what the USB cable and connectors actually look like:
As mentioned earlier, the USB port can power certain devices and also transfer data at the same time. For this to happen, the USB port must have at least four cables of which two are for the power, and two for the data.
The diagram is to help you understand what the cable contains:
The USB DCC (finally)
The USB DCC cable can also be used to connect a computer to your network. The way it works is pretty simple. Assuming you have Computers A, B, C and D. Computer A, B and C are connected via an Ethernet LAN and Computer D hasn't got a network card to connect to the network. Using the NET-LinQ or other similar cables you can connect Computer D with any of the other 3 computers as long as they have a USB port, then by configuring the network protocols on Computer D, it will be able to see and connect to the rest of the network!
This completes the discussion about USB Direct Cable Connection.
Network cable, lesson 1, Introduction
Network cable, lesson 2: Straight-through UTP cables
Network cable, lesson 3: CAT5 UTP x-over cable
Network cable, lesson 4: 10Base-T/2/5/F/35 - Ethernet
Network cable, lesson 5: 100Base-(T) TX/T4/FX - Ethernet
Network cable, lesson 6: Fiber
Network cable, lesson 7: Direct Cable Connection
Network cable, lesson 8: Serial Direct Cable Connection
Network cable, lesson 9: Parallel Direct Cable Connection
Network cable, lesson 10: USB Direct Cable Connection
Testing network cable
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