Networking DSL/Cabling Issues

[Garrett Goebel]

Adam Davis wrote:
>
> I'm trying to set up a home network so that several computers
> can share a DSL line.
>
> The setup is such: DSL modem is on the second floor and the
> router must also be there.  Computers are on the first floor
> and in the basement. Each computer currently has cable running
> to it from the 2nd floor.

DSL modem is a misnomer. DSL stands for Digital Subscriber Line. Modems
modulate digtal data into audio, and demodulate audio to digital. I.e. mod +
dem = modem. DSL devices are digital <=> digital... no modulation required.
So you might ask, if you haven't got a DSL modem, what have you got?
Probably a DSL bridge, or possible a DSL router.

A bridge operates at the data layer in the osi model, which in your case
means ethernet. A DSL bridge would require no ip address, and would
basically just forward ethernet packets. A router operates and forwards the
network layer, in this case IP.

Getting your terminology straight avoids unnecessary confusion. You might
consider reading:
https://secure.linuxports.com/howto/intro_to_networking/c4412.htm

Can you supply the make and model of your "dsl modem" and "router". This
would help disambiguate the situation. Until I know what the hardware is...
it's hard to tell you how to hook it together.

The patch cable issue is probably a matter of which are straight-through and
crossover cable. You can tell by looking at the color ordering of wiring in
the RJ45 jack. RJ stands for Registered Jack. You can read up on them at:
http://www.arcelect.com/RJ_Jack_Glossary.htm

An RJ45 jack is the 4 wire-pair plug. 10BaseT is the wiring scheme. CAT5
describes the cable. You can read up on it here:
http://www.netspec.com/helpdesk/wiredoc.html. It has nice images which
should help you visual check whether you're looking at a crossover cable or
not.

Where do you need a crossover cable? If you want to hook 2 computers
together without a bridge, hub, router, etc. you could use a crossover
cable. Or likewise if you are connecting 2 hubs together and the hubs don't
provide an uplink port or switch. But in the normal case of connecting a
computer to a hub you use a straight through cable.

So starting with your working scenario... figure out which cable is straight
through, which is crossover and get or make cables of the appropriate
lengths to move the hardware where you want it.

It is also possible that you could move your DSL modem elsewhere. I don't
know why you feel it has to stay on the 2nd floor. I don't know if you are
using microfilters or a pots splitter. Probably microfilters. Microfilters
can be moved. Telephone wiring is as easy to install as CAT5 10BaseT.

Or you might consider contacting your phone company or a telcom vendor and
ordering a POTS splitter. It isolates the frequencies used for voice and
data and allows you to split them out onto separate wire pairs. You could
install it out at the NID and feed the DSL in through your 2nd pair in you
telephone wiring. Assuming like most of us you have 2 pair phone wiring.
This would put voice through the red/green pair and data through
black/yellow. I'm not certain, but I believe most DSL bridge|routers use the
second pair. At least my Alcatel 1000 does ;) So you could potentially use
the same phone jack for either voice or data. Check your manual. Someone
correct me if I'm wrong.

NID stands for Network Interface Device. And is phone company nomenclature
for the phone box usually located and fixed onto the outside of your house.

hope this helps...

> Included with the router was a short bit of patch cable.  The
> instructions specifically say to use the patch cable to connect
> the router to the computer, and use the cable currently hooked
> into the DSL  modem to connect the modem and router.
>
> Using that setup requires me to put the router right next to
> one of the two computers and it works.  The problem is that
> the router needs to be with the cable modem on the second
> floor, so I can connect both computers to it.
>
> But when attempting to do this, I have to use the patch cable
> to connect the modem and the router (and leave the line that
> runs from 2nd floor to 1st floor connecting the router and
> the computer).  With this setup, nothing nothing happens.
> The computer doesn't even recognize the router.
>
> The DSL modem needs a 10BASE-T connection, but I'm not
> precisely sure what that means.  Do I need to get a different
> type of networking cable?  Is there somethinge else I'm
> completely missing?
>
> Any help would be greatly appreciated.

--
Garrett Goebel
IS Development Specialist

ScriptPro                  Direct: 913.403.5261
5828 Reeds Road            Main:   913.384.1008
Mission, KS 66202          Fax:    913.384.2180
www.scriptpro.com          garrett at scriptpro dot com