Wael Khalil wrote:
Hi guys
I'm only a student
I'm trying to connect two computers together using the usual USB cable
which ends with two male connectors on both sides
so I cut the power wire within the cable
and connected the two computers to their USB ports
I used the jusb API for Windows and javax-usb to do that
but java didn't recognize any device on any port even though I know that
the root hub
is a device (isn't it)
So I'm asking your help because I have to handle this project to my
supervisor in no time (Pleeeeeeeeeeeeeeease)
1- I want to ask you guys is it about the cable:
I mean that did I ruin the cable when I cut the power wire in it?!!!
Could it work if I didn't cut that wire (I thought that the ports might
be damaged or even the motherboard culd be damaged also) is my thought
right or not.
You should NOT connect the 2 computers with a home made cable, it will
not work, and if the computers are on different potential levels you
could get a power rush.
(Earlier I connected 2 ungrounded computers using a BNC cable, and you
could actually see sparks going from from one of the computers to the
shield of the cable before they connected and had a common ground via
the cable shield.)
Not e: There's a USB device in the market which can be used to connect
two windows systems together, I am not allowed to use it.
Too bad, that's probably the only way you could connect two computers
using USB.
2- Or is the whole idea is wrong and I can't connect two PCs through usb
ports
using Javax-usb?
Javax.usb is for communicating with the devices. With the special cables
used to connect two computers there is actually a device in the middle
which both computers (hosts) talks to.
3- Can I do this through USB hub?
If the answer is Yes I can connect the PCs by the help of Java over USB
ports
please send me a solution (How to connect the PCs) and a code to begin with.
and if I can't do it please tell me why.
There are several technical reasons why this can not work, USb does not
use a protocol with collision detection or some other kind of
collaboration to get multiple devices to share a common cable. Instead
there is a host (the computer) which tells each device when it can send
data. Now, if you take 2 computers and connect them together they will
both try to control the bus.
For more information of how this actually works I'd recommend reading
the specifications at www.usb.org.
//Roger
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