Wednesday, April 29, 2015

USB, What is Means

Alright, I know it has been a long time since my last blog post but I think this one is pretty interesting, at least to me it is.  This one is also going to be a bit more technical than you may anticipate, but I will try my best to make it as understandable as possible.  Today's topic is about USB.

That's right, this post is about that Universal Serial Bus (USB) that you probably use every single day and probably never gave a second thought as to how it works.

There are several types of USB connectors that have various uses:



The most common types you have probably encountered are the Type A and mini USB connectors. The difference between the Type A and Type B is Type A is typically for a host, that is, the device that is sending out the information, and Type B is for the device that is receiving the information.  Nowadays, a lot of deices that use USB can both receive and transmit data so Type A is the most common.




If you ever look at a USB plug closely you will most likely see 4 or 5 connectors.  Typically the two outside pins are used to supply the Voltage as well as the Ground.  So when you connect your phone into the wall to charge it, it is only really using the two outside pins, and the two in the middle aren't being used at all.

This is the part that I found most shocking, there are only two pins used to transmit the data, the two middle pins and these two pins send the same exact data, just one is the negative of the other.  This is called a differential pair and I am not going to go into the specifics of why they do this, other than that is to ensure that the the signal received is clean and free of noise.  I think the fact that these two little pins can transfer over a billion 1's and 0's in a few seconds is amazing, and I know if someone asked me to design a device to do that I would have to use way more than two pins.

I guess that is just something to think about when you are uploading pictures from you phone to your computer.


Picture 1
http://www.l-com.com/lcom_emails/2008/092308/usb_connectors_sm.jpg
Picture 2
http://newnex.com/images/ura-1001-clear.jpg

2 comments:

  1. The second paragraph is absolutely right – I've never thought anything about my USB drive, I didn't even know it was called a Universal Serial Bus. I also had no idea that there were so many different types of USB drives. I was only familiar with the Type A version. That is odd that although there are several pins, only two are used. How interesting that those two pins alone transfer all of the data, billion of 1's and 0's as you said. I will definitely now have a heightened appreciation for my universal serial bus the next time I'm jamming it into my computer.

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  2. Due to my years in a vocational technical high school concentrated in studying information technology, I knew were you were going with this post. You were completely right about people not knowing about the USB even though they use it everyday. I am actually using a Type A USB as of now to charge my laptop and a micro USB to charge my cell phone. It is truly amazing how technology can advance so quickly to the point where a simple USB is used everywhere. I find this post interesting. Keep it up!

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