So Telus sent me a new modem (Siemens Gigaset Se567) the other day as a part of a new promotion. Since I have my existing modem I'd like to set it up for my laptop in another room. I don't have enough ethernet cable to reach anywhere away from the desk and no wireless card, so it's gotta be a wired connection.
but for some reason when both modems are plugged in (to the same phonline) they don't work, but both work perfectly well on their own. I have registered both modem's mac addresses and checked/replaced all my wires, but am still stumped.
so my questions are these:
is this just a data conflict within the adsl line itself?
how do I fix it?

Actually as far as i know they cant work like this, ADSL line need to access the very start of the line before any phone or device to work, again i am not sure of that but thats the instructions which i got from the ISP here, plugging the splitter before any phone line then connect the phone lines line to the splitter.

well there are no phones on this line, it's a dryloop connection. and I have it set up like so:
Wall-splitter<two phone cables=two modems.

As far as I know it's not going to work. The only way to get it to work is to get another line coming into the house. Think of it as putting two satellite receivers on 1 cable connection from the LNB. Each receiver needs it's own connection from an LNB and in your case your modem needs it's own connection, they're not going the share the same line.

Think of it as two dial up modems on the same phone line. When one dials out and gets a connection, the other one isn't going to be able to dial out because the line is in use.

I'm fairly sure this is never going to work. I can see how it is possible. But you would need special modems, set up to use different frequencies on the line - Never going to happen - The phone/internet network may not even support that.
You would probably be better off using 1 modem over a wider range of frequencies than 2 split anyway.

What you need to do is buy a router to share the internet between the two machines you have and run ethernet cable or setup wireless. Its the only way really. If you really can't run new cables, or wireless doesn't work well in your building. You could try power-line networking. However I think wireless would be best as its cheap and easy.

I agree. Wireless would be the way to go in your situation. Even the cheapest wireless router would do the job for you.

well my new modem has full wirless/wired routing capabilities. as well I have an old wired router too. I just don't have long enough ethernet cable to run a wire to the other room and also, I've no wireless card.
oh well, I was just wondering if it was possible with what I've got already before I tore the place apart trying to make it work.
thanks for the replies all.

Well if your new modem supports wireless routing, why don't you set it up and buy yourself a USB wireless dongle? They cost like £20 for a good one. Would solve your problems with ease. A slightly harder installation and you could get a PCI one, probably a little cheaper. There are some really cheap brands out there that would do the job for £10.
Here is a whole load, from under £10 upto about £50.
http://www.ebuyer.com/cat/Wireless/subcat/Adapters---USB

This Belkin Wireless G looks good for the price:
http://www.ebuyer.com/product/75646

Try looking for that locally to cut out any shipping charges. Its really quite simple to set up and use.