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Tech Tips: Rewire USB Ports

Tech Tips: Rewire USB Ports

Why you should consider it: Get something for free! Making two ports where there was one can work if you remember the rules.


It began with a thought about splitting a USB connection. It could be done. It seemed logical to have two where there once was one. This thought arose because the motherboard had one USB header where two were required. It seemed a whole lot easier to split a USB cable than to replace an entire motherboard. Could the USB ports on a PCI bracket at the rear of the case be spliced to the USB ports at the front of the PC Case? The rules of technology can be bent but sometimes they snap back.

The motherboard has two USB ports on the backplane and a single header on the PCB. When USB was first integrated into motherboard design two and four USB ports were thought to be enough. Well four wasn’t enough. The Gigabyte dual processor motherboard in question had the mouse residing in the first. The USB keyboard took up the second. The KVM used up the third and the printer occupied the fourth. Now the digital camera needed a fifth which didn’t exist and I thought not of continually crawling under the desk to switch USB cables. So the thought got thought of thinking to splice a USB cable. It made sense. It was a plug after all and where there was one wire…could there not be two? Why spend money for a solution when it can be free!

The phrase "it was a great idea but…" applies best in hindsight but it certainly didn’t come up during this process.

The goal was to enable the USB ports at the front of the PC case by splicing them to the USB cable that was for the USB ports on the PCI bracket at the rear of the case. Again…it made logical sense at the time.

pc_case_usb_area

pc_case_usb_area_cu

So the great plan came to life or so this is what I thought. Out of the case came the front USB wires to be made bare to the world.

wire_outofcase

The Lian Li PC70 case and many others now come with front USB ports and the wiring harness that plugs into an available USB header on a motherboard.

usb_wires

Many motherboard packages also come equipped with a PCI USB bracket in order to provide USB ports at the rear of the case by way of the header.

pci_bracket

These PCI brackets have a plug to match the USB pin header on the motherboard.

cu_usb_connection

The plug can be removed or rather the wires can be removed from the plug. Use a jeweler’s screwdriver to release the wire pins from the header. There’s a plastic tab that can be gently pried up to release the pins from the plastic plug.

stripped_wires

There soon followed much snipping of the wires.

snip_wires

There are times when we do use those melons on top of our shoulders and the great book of the motherboard was consulted.

manual_usb_wiring_cu

Before the snipping which was to be followed by the stripping and the stripping was to be followed by a lot of twisting came the reading. It’s important to RTFM before snipping wires to know what wires have to be spliced to each other prior to soldering. The manual provided the answers to what wire got twisted with what other wire in what particular order so everything would or could have the slightest chance of working correctly.

So after the great book of the motherboard was consulted came the welding.

ws_soldered

Actually it was only soldering but welding sounds far more exciting when modding. All of the wires were properly twisted and double checked before soldering.

cu_soldered

After the soldering came the wrapping. Be it shrink wrap or traditional tape…the wrapping is crucial otherwise when soldered wires touch each other or other metal parts the darkness could come. This could very noticeable when the place where you sit plunges into darkness as the lights go out due to fuses tripping within your home. It could also be the place inside your head as you realize you’ve just fried your system because you forgot to RTFM. A fact made more real by that acrid plume of smoke.

Warning: Electronics are a wonderful thing but when asked to do something they weren’t designed to do they can bite back. All modifications are at your own risk. The result could simply be a connection that doesn’t work, a damaged component or, at worse case, burning down your home.

 

Eventually all of the wires were soldered and the connections were wrapped. Always use proper insulation when dealing with low or high voltage connections.

wires_wrapped

wires_wrapped_cu

The first challenge was to take the octopus of PCI bracket and front USB ports and put it back from where it came; somewhere inside the PC case.

ws_case_guts

Did it work?

The moment of truth came. Was technology cheated? Yes and no. All of the USB ports worked. A device plugged into each of the USB ports was detected and functioned normally.

Then the wheels fell off of the master plan.

The USB mouse and keyboard were plugged into the two USB ports on the backplane so they can be ignored. The KVM was plugged into one of the USB ports on the PCI bracket at the rear of the case which shared with one of the USB ports spliced from the front of the PC case. The USB printer plugged into the other USB port on the PCI bracket at the rear of the case which shared with the other USB port at the front of the case. The USB camera, the fifth USB device could now plug into the front of the PC case due to the mod.

And it worked!

In one port but it didn’t work in the other. Before all of you smart ones raise your hands and exclaim "I know…I know!" let’s give the rest of the class a chance. The KVM unit draws power from the USB port and communicates through it. It’s always on. The printer only communicates through the USB port and it was powered off. The USB camera worked in the port that was sharing with the printer…but didn’t work in the port that was sharing with the KVM. So why didn’t it?

The power of mine.

The power of mine is a simple way to remember the rule of USB. When a device is powered up on or draws power from a USB header it says "MINE!". The device, in a way, maps a connection from it through the USB header to the rest of the motherboard. Remember that this modification makes a Y-splitter where normally there would be a direct connection. One side of the "Y" is now occupied by the functioning USB device effectively blocking the other side.

So does this mean, for example, when a USB printer shares the same header with a USB camera that if one or the other is off then the other will immediately work?

No.

If both USB devices have a power ON/OFF button such as a printer then both devices can remain plugged in. The process of powering up one device will "clear the way" to the USB header. This only works if both devices are powered off. Power up one device…use it…power it down…then power up the other device for use.

But if one or both devices draw power FROM the USB header then the wheels fall off. A device connected to the USB header will hang onto the connection even if the software for it is shut down and the device is "powered off." The USB powered device will block the other USB device even if that device has a physical ON/OFF switch. The solution is simple. Unplug the USB powered device then power up/plug in the other device.

USB has a convenient plug and play feature. A USB device can be plugged into any USB port as long as it was properly set up to begin with. USB devices don’t always need to be plugged into the same port they were initially and properly set up on. USB devices cannot share the same header simultaneously with additional help. That’s why USB hubs were made. USB hubs have additional circuitry that allow for this but they cost money…not much but the point of this modification was to get something for nothing.

Making two ports where there was one can work if you remember the rules. If more USB ports are required to be active simultaneously than are available then go spend the $10-$20 for a PCI card that adds 2 or 4 more USB ports or buy a hub because two devices sharing the same header without additional circuitry…just won’t work.

Happy Modding!

Comments

  1. mmonnin
    mmonnin Another ones of MM's ingenious ideas.

    Sounds like it should work tho. That can be kinda handy if you dont have enough USB ports.
  2. Omega65
    Omega65 Nice Article MM! :thumbup
  3. Unregistered
    Unregistered That all very good but what happens when you open your case to try something like this and you find.....................usbcable1.jpgimg]
  4. Unregistered
    Unregistered Sorry above link should have been :-
    [url=]http://www.flyservers.com/members5/bernievink.com/images/USBcable1.jpg[/url]
    still was a lot of trouble soldering a large number of wires and then making sure of the right connections. eventually all worked but it was a struggle
  5. floppybootstomp
    floppybootstomp Nice article, MM :thumbsup: Nice way to give a choice of where to plug in. I have two black versions of that case, the PC-61, I think, so I could relate easier.

    Unregistered: No pain, no gain mate, basically, but it's good to see you got it sorted :)
  6. seatech1
    seatech1 I tried this without knowing about the multiple device problem (etc.). And I had problems with it. So this idea won't work for me, but at least now I know why! Excellent article including "pictures with circles and arrows on the back of each one."
  7. Unregistered
    Unregistered Similar mod but on the notebook motherboard:
    http://www.notebookforums.com/showthread.php?t=92207

    Thanks for the article, it helped me in the mod!
  8. Yes, your ports are mutually exclusive. And your description of "Mine" is a good theory, but it isn't about who is powered. Many devices (like your camera and printer are separately powered. A better metaphore would be listening to two people send you morse code on the same line. If one person sent dot dot dash while the second person was sending dash dash, you would only hear the dashes. From the point of view of the listener you are just going to hear a whole lot of dashes. The information from both senders is destroyed and unrecoverable.
  9. Pterocarpous
    Pterocarpous
    MediaMan wrote:
    Could the USB ports on a PCI bracket at the rear of the case be spliced to the USB ports at the front of the PC Case? The rules of technology can be bent but sometimes they snap back....

    Hi All
    I'm fairly new to SM and am still learning my way 'round the site. I've been trying to get at some of the Articles but, in a few cases so far, can only find their corresponding threads - not the articles themselves. Some I've found a link to the article in the 1st post of the thread but others I have not (e.g. Dual Core Explained & Demystified).

    Could you, please, tell me how I might find these articles?

    Thank you!!
  10. Trogan
    Trogan Hey Pterocarpous! :)

    Links to Articles should be on the first page. The "here" part "Read it here" is the link to the Article.

    Link to the Article you could not find:
    http://www.short-media.com/review.php?r=261

    Hope that helps! :)
  11. Linc
    Linc You can actually browse by category on the front page. Click the "Reviews & Articles" tab. Now, it looks like a blank page, but it's not. There's a table element out of whack and the list appears after the END of the left column instead of next to it. I've tried to fix it but I can't figure out which table element it is :-/ Sorry for the inconvenience, and let me know if you need help finding anything in particular. There will be an easier system in place by the end of the month :)
  12. Pterocarpous
    Pterocarpous
    ...You can actually browse by category on the front page...
    Trogan wrote:
    ...Links to Articles should be on the first page. The "here" part...
    Thank you General. I did finally stumble onto the front page and found the articles listed there. I spend so much time in the forums, I forgot all about the home or front page of SM's site.

    Thank you, too Trogan. It was via the embedded hyperlinks in the threads that I had been able to find some of the articles. Thank you for the link to the review.

    The other day, I tried to find a Sticky that referenced some technical "how to" info. I'd run across the Sticky b4 and wanted to provide a link to it for someone in one of the forums. (sorry, I just plain can't remember what it was about now - old age - it's already fallen outta the back 'o mah haid!) I tried "Search"ing but no worky.

    Is there an index of all the Sticky's per chance?
  13. Linc
    Linc Sorry, no sticky index :-/ Just gotta check the individual forums.
    I forgot all about the home or front page of SM's site.
    I get this a lot :( I have a plan to change that as well, though.
  14. Pterocarpous
    Pterocarpous
    Sorry, no sticky index :-/ Just gotta check the individual forums...I get this a lot :( I have a plan to change that as well, though.

    Rats! Well, I know it takes a helluva lot o' upkeep to maintain this forum and ya'll are all volunteers for the most part. You're doin' one hec of a job BTW! So, if you get to the index, f-a-b-u-l-o-u-s. If not, I certainly understand. I'll just have to pay attention to where I find stuff! :tongue:
  15. josh
    josh thanks for this:i'm going to take the board out of a usb hub i have and strip it, add the header plug and plug it into the header port (should stand up like a damn board extension) then plug other header into it voila home brew internal, switching usb header extender
  16. clifford_cooley
  17. Lydia Hill
    Lydia Hill Hi, I have an embroidery sewing machine which has a usb port. I got it refurbished from overstock.com the machine I bought was a brothers se350 which are not suppose to have usb ports. the Se400 has the port. Any how mind has a usb port and it is not connected to the computer board that is in the sewing machine. Can you tell me how to hook it up.
  18. BuddyJ
    BuddyJ whatlaptop.jpg

    Just plug it in.
  19. CB
    CB
    Lydia Hill wrote:
    Hi, I have an embroidery sewing machine which has a usb port. I got it refurbished from overstock.com the machine I bought was a brothers se350 which are not suppose to have usb ports. the Se400 has the port. Any how mind has a usb port and it is not connected to the computer board that is in the sewing machine. Can you tell me how to hook it up.

    If I'm reading this right, you have a SE350, and the refurb guys put a USB port into the case somehow? Are you sure that they didn't send you a SE400? It would be a really strange thing for a USB port to magically appear on a SE350.

    If you do have an SE350 with a USB port, there wont be anything you can do. The SE350 only supports programming from the on-device screen, so the computer board inside will not have connections for a USB port.

    If you have a SE400, it should already be hooked up, and if somehow it's not, then you need to return it for more service. However, the SE400 only has a USB port for updating the software, you can't program the device from the PC or hook up a mouse.

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