I wanne use my Arduino as a home made interface to Controll a computer, the only problem is that the interface and the computer are like 50 metres appart. I can buy an USB -> CAT5 -> USB extender to solve this.
The thing is, an USB1.1 one costs arround 100 euro, while a device for USB 2.0 is arround 800 euro.
So my question, what USB does the Arduinol needs, since the data transfer is based on RS232, I assume it can run on the old USB1.1.
Hope some one can tell me this.
THANKS ALREADY!! 
50 meters is a long distance. If you want to go with a USB-only solution, you can try using cheap Chinese usb 1.1 extension cables:
http://www.geeks.com/details.asp?InvtId=100E&cm_mmc=Froogle-_-Cables-_-USBCables-_-100E
they're 30 meters, only $19 each, and if you put a hub halfway between them you could probably keep them going.
I'm using one of these lengths to successfully control an Arduino solar heat sufficiency controller down in the house's boiler room.
You could get one of the arduino serial boards and use an rs232 port (or a usb/rs232 adapter) on your computer. rs232 will run longer distances than USB, and do it a lot less expensively. You'll also have your USB arduino left to play with.
-j
So the Arduino is USB1.???????????
(was the only thing I wanted to know)
Thnx for the replies, and mentioning the USB extendercable, very interseting.
Ehh... a decent RS232 Cable off that Lenght will cost the same as that USB1.1 - CAt5 converter.
Also, cabling cat5 (AKA standard network cable) is way more easy since the plugs are very small.
So the Arduino is USB1.???????????
The FTDI website http://www.ftdichip.com/Products/FT232R.htm says the FT232RL is "USB 2.0 Full Speed compatible". It'll also work at USB1 rates. hope that helps.
Ehh... a decent RS232 Cable off that Lenght will cost the same as that USB1.1 - CAt5 converter.
Also, cabling cat5 (AKA standard network cable) is way more easy since the plugs are very small.
Ah, not sure what kind of cabling you are buying, but for 100 euro you should be able to buy a lot of rs232 cable. For low rs232 data rates (9600 baud or less) take any old wire, for instance that cat 5 you were going to use, and run it. Yeah, there are lots of specs and lots of spiffy commercial rs232 cables with nice molded connectors and shielding and all that, but for low speeds it's unnecesary.
DB9-RJ45 shells are US$2 each, use 'em to make rs232 cables from cat5, or from flat 8 conductor phone cable. I use dozens of such cables for rs232 in my server room.
-j
There where also some touchscreens near the place I wanted to use my arduino, they usesd RS232 cable, remebered it was very expensive, but now we have the USB1.1 -> Cat5 extendere solution, and we can also use a mouse and keyboard for debugging.
Hope I can simply plug in my Arduino and make it work.
Thank you for the reply kg4wsv.
So, basicly you say, you made your own RS232 cable (sorry, my naming convention isn't soo good, but I asume you know what I mean) buy taking some piece off Cat5cable, and solder your own connetors, and it works? That trick is great to know 
But I serious wonder about the shielding problem you will have, than again, as you said with low data-rates it should not realy mather. Think I could try it with some trial-and-error, hehe.. low budget rules 
Once again, thank you for your time, I am just a beginner to this great world off electronics.
So, basicly you say, you made your own RS232 cable (sorry, my naming convention isn't soo good, but I asume you know what I mean) buy taking some piece off Cat5cable, and solder your own connetors, and it works?
It's even simpler than that. Instead of solder type connectors, use these:
and simply plug the cat5 patch cable's RJ45 into the adapter. The db9-rj45 adapter comes with 8 pins and an empty shell, so you can get the pinout you need by simply plugging pins into the appropriate holes in the connector.
If you were extremely worried about it you could use solder type connectors and make sure two different signals aren't using the same pair, or even use a pair as a single wire. I've never gone to that sort of trouble, though. I typically tie the pins one for one (pin 1 on the rj45 goes to pin 1 on the db9, etc) on one end. On the other end I do the same for a straight cable, cross 2 and 3 and wire 5 to 5 for a three wire null modem, etc. A full null modem with hardware handshaking can get a bit more complex and require a bit of soldering, but no worse that wiring the whole thing with solder cup connectors.
But I serious wonder about the shielding problem you will have, than again, as you said with low data-rates it should not realy mather. Think I could try it with some trial-and-error, hehe..
That has been my experience, but as they say, your mileage may vary. (: I have a production system (security cards/door locks) that uses a 50 ft cat5 patch cable and two db9-rj45 adapters for an rs232 cable. It's used many times a day for the past 5 or 6 years with no problems whatsoever. I think it runs 9600 baud.
I know that quality RS232 cable is usually shielded, but I'm not sure if the rs232 (EIA-232 to be more accurate) specifications call for shielding.
Good luck on your project!
-j
If you wanted to run wire over even longer distances, you can look into RS-422 converters, which is an industrial serial link, that makes use of differential signals. Just like ethernet does. What this basically means is that you get much less interference and you can run hundreds of meters of cable.
Like with the pre-molded cables: if you buy a commercial RS-232 to RS-422 converter it is bloody expensive, but if you solder your own chips it's the same price as RS-232.
The USB to Ethernet solution also works fine ofcourse, if you can spare the money.
Well, since RS422 was mentioned I have to add RS485 which allows up to 1.2 kilometers of cable lenght at 100kbit/s (same as RS422 I think) and is quite common, too.
Does anyone have a link for how to build your own RS232 to RS4xx converter?
this guy does....
DIY RS232-RS422
http://chaokhun.kmitl.ac.th/~kswichit/Rs422/Rs422.html
Also, the MAX3081 is a very easy-to use chip for TTL levels to RS422, and they will send you free sample chips too!
D