Imagine for a moment with a 4 port USB hub. Normally how this would work is the hub has one plug that goes to the computer, then 4 ports that you can plug in other things to (thumb drive, keyboard, mouse etc). I am wondering if I can use it in reverse. So I would have 1 keyboard going in to the hub, and then plug in male to male usb cables from the 4 ports to 4 different PCs, my aim is that when a key is pressed on the keyboard all 4 PCs will receive it as if the keyboard were plugged in to them.
Does anyone know if this would work? And if not does anyone have any ideas how I could get the same effect?
EDIT: So I am looking for more of a KVM switch type device rather than a USB hub. However all of the KVM switches I've found use some sort of mechanism to select which computer you'll be using. (some are physical switches / buttons, others do it via software "automatically" some how)
However I need to have 1 keyboard hooked up to 2 computers and when I press a key on the keyboard I want the keypress to be sent to both computers simultaneously, not to one or the other. Does anyone know if KVMs with this feature exist?
75 Answers
No. Definitely not.
What you want is a USB KVM switch - Keyboard/Video/Mouse switch. It shares one screen, keyboard and/or mouse between multiple computers.
Alternatively it can be done through a network using Synergy.
1You indeed need a KVM switch.
You should understand the concept of USB. Your computer is a host, a USB hub is a device + host. It's device on the computer side, but once again a 'host' for the subdevices. The way you have drawn up picture 2 is suggesting that the PC would be an USB device and the keyboard a host, which neither can do.
This is a reason USB B, mini-B and even micro-B are invented. They are mostly used for connecting a host (normal USB plug) to a device (normal/mini/micro B connector).
2What you are looking for is a USB "splitter". Such a thing does not exist. Although this is conceivable to do in the keyboard example, where information is being passed only in one direction, it would fall apart with other types of USB devices that want to have a conversation with the computer, because it would be ambiguous which of the two computers would respond to the device. You can do splitting with something like a VGA signal because you don't get this sort of conversation going on (even though there is bi-directional signaling going on, it can be handled by a splitter).
4A standard USB hub will not work in reverse.
I suspect it may be possible to adapt the Synergy software to do what you want to do, entirely in software.
It may be possible to splice together pieces of several USB hardware projects to do what you want to do -- connect USB keyboard to Arduino; have Teensy Arduino send keypress information to a host PC ( a and b and c ); and somehow combine them ( d ).
It is possible to run a sync with 2 keyboards, it would just be a matter of wiring in the keyboard before the serial port, I would not know how to do that today.
Hardware Broadcast with PS2 (costly box) USB also (really costly box)
And "multiBoxers" are using some macro type software to play with themselves (umm in the MMORPG of course :-) . I would ask there, especially if it was for that purpose. Multiplicity probably similar to other small tool items, and VNC style KVMs.
With enough time in a search like this Google search term You could probably find a way to broadcast a keystroke with the least ammount of load on the pc.
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