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I have a camera system at home with a DVR, which connects to a VGA monitor and mouse with which you can read and edit its settings (the cameras can be accessed over the Internet). I've been trying to move the monitor out of the closet it was in before (that's where the DVR is) to a more convenient spot, on a desk in my room. As it turns out there is a Cat5 cable that leads to the closet from my room, and I was able to splice together a VGA cable to both ends of the Cat5 wire, which allows me to see the video feed from the DVR. The VGA setup I have uses 6 of the 8 wires in the Cat5 cable, leaving 2 behind. I wanted to also connect a USB mouse to the DVR from my room using the Cat5 cable, however you'd normally need 4 wires in Cat5 cable in order to do that. Despite this, I tried to run the USB mouse's Data+ and Data- through the Cat5 cable's remaining pair of wires, and I connected the VCC and Ground wires to a power supply. The mouse was powered (ie it lit up) but it did not appear to be controlling the DVR from my room despite the data cables being connected. Is there any way to run only the USB data through Cat5 and not VCC and Ground? This would allow me to run VGA video and USB through the same Cat5 cable, which I am hoping to do.

Here's the current setup, where the mouse is powered but not "connected:"

                         To   <----VCC------+ (loose)
                        DVR's <----GND------+ (loose)
                         USB  <----------+         To DVR's VGA out
                         in   <--------+ |  D-      ^ ^ ^ ^ ^ ^
                                       | +--------+ | | | | | |
                                       +--------+ | | | | | | |                                        
             External USB Power Supply      D+  | | | | | | | |
               (an iPhone wall USB              | | | | | | | |
                 charger adapter)          (cable goes through walls)
                        ^   ^                   | | | | | | | |
                    VCC |   | GND               | | | | | | | |
                        |   |            +------+ | | | | | | |
                        |   |         D+ | +------+ | | | | | |
                        |   |            | | D-     | | | | | |
                        |   +----------+ | |        V V V V V V
                        +------------+ | | |       All VGA video,
                                     | | | |         to monitor
                                     V V V V
                                     To Mouse
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  • \$\begingroup\$ How long is your "extender"? Just curious about your VGA results... \$\endgroup\$ – Ale..chenski Jul 17 '18 at 17:03
  • \$\begingroup\$ The video isn’t perfect, but it gets the job done. It appears “smeared” to the right a little. \$\endgroup\$ – BoomBoomPowe Jul 18 '18 at 16:50
  • \$\begingroup\$ Again, how long is your cable? It is important as a reference point, and for future readers. \$\endgroup\$ – Ale..chenski Jul 18 '18 at 19:08
  • \$\begingroup\$ Oh, sorry. Since it goes through the wall, it is hard to tell, but my best guess is that the cat5 cable is around 25-35 feet long. \$\endgroup\$ – BoomBoomPowe Jul 19 '18 at 19:19
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Your circuit is missing a common GND between the mouse and the DVR. This alone prevents USB from working correctly.

There is another issue: The CAT.5 cable is not suitable for USB - wrong impedance. It is also highly likely too long.

But there might be a simple solution: Try one of those wireless mice.

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  • \$\begingroup\$ For low-speed mouse the cable impedance doesn't matter. For 667 ns bit pattern of LS mouse the cable length doesn't matter much as well. People had reported 30' successful run of gaming mode mouse, gamespot.com/forums/pc-mac-linux-society-1000004/… But +1 for missing ground. \$\endgroup\$ – Ale..chenski Jul 17 '18 at 17:00
  • \$\begingroup\$ Wireless mice could work, but I was just kinda experimenting with the system to see if I could run USB over Cat5. Thanks for your answer! \$\endgroup\$ – BoomBoomPowe Jul 18 '18 at 16:52
  • \$\begingroup\$ There is a ground cable on the VGA circuit, so I can wire it up to have a common ground and test it out. \$\endgroup\$ – BoomBoomPowe Jul 18 '18 at 16:53
  • \$\begingroup\$ I connected the GND of the VGA circuit up to the GND of the USB, and it worked! Sweet. \$\endgroup\$ – BoomBoomPowe Jul 19 '18 at 19:20
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For the common GND you could use the shielding of the Cat5 (if there is one).. and the USB power could come from a regular USB power supply..

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