[Gllug] USB-over-CAT5

[Chris Bell]

On Tue 20 Feb, Matthew King wrote:
> I have two computers at opposite ends of the house which need a
> serial-line connection between them. There is currently a length of CAT5
> cable between them and pulling up floorboards does not sound pleasant.
> 
> I have tried an external ADSL modem (so that the router can be moved
> closer to the network hub (and therefore within range of a regular
> serial cable) but external ADSL modems all appear to be pretty
> crap. D-Link's DSL-320T, for example, categorically does not (according
> to their technical support) allow me to use more than one IP of my IP
> range.

   You usually need to turn off NAT and Firewall on the ADSL router. I only
have a single IP address, so have not bothered to try it. I am now using a
HiPoint ADSL2+ router with switch, 4 ports plus wireless, it is based on the
TI-AR7WRD and appears to be totally configurable, including bridge controls
between inputs and outputs. It just sits at the absolute maximum bit rates
and works. Select "UK" to get the UK defaults. Import and trade distribution
by friends, please mention GLLUG.

http://www.3adl.com

> 
> The next best solution, therefore, is to use the existing cable to
> transmit serial data. Lots of very expensive devices are available to
> coerce USB or RS232 onto IP, however I am considering a more
> basic configuration on which I ask GLLUG's advice:
> 
> CAT5 cable has 8 wires. Ethernet uses 4. USB uses 4. 4 plus 4 equals
> 8. Perhaps you can see where I'm going?

   Gigabit ethernet uses all four pairs.


   As an alternative, I have seen a pair of USB to Cat5 converters to extend
USB


> The four wires which Ethernet doesn't use I'd like to remove from the
> RJ45 connector at each end. At one end plug them into the USB socket in
> the router. At the other connect a USB-to-RS232 converter into which I
> can plug a short null-modem serial cable.
> 
   Converters between Cat5 pairs unused by 10baseT and telephone are
available, and splitters used to be available to allow two ethernet or both
ethernet and telephone, (but take care not to connect between telephone and
ethernet).




-- 
Chris Bell

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