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.
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.
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.
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.
These PCI brackets have a plug to match the USB pin header on the motherboard.
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.
There soon followed much snipping of the wires.
There are times when we do use those melons on top of our shoulders and the great book of the motherboard was consulted.
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.
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.
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.
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.
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?
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.