wireless network advice

[Psyduck]

OK, my parents live in France and have broadband over there. I'm wanting to give them my old wireless router so they can go wireless.
At the moment, they have a big box that sits next to the phone line, it seems like a plain wired router, but it's pretty big, so I'm guessing it does other stuff too. It has an ethernet cable coming out that they plug into the PC to surf the net.
Can I plug my wireless modem/router into that via ethernet, and then connect to the router through wi-fi? Or will my modem/router need to make its own internet connection directly? Can it do that? Or is france different?
No real problems if your answers are guesses, it's not going to cost to try it, just be nice to know beforehand really.

[Pavey]

Sounds like it should be fine mate,as that is what i do.

I bought a Netgear wireless router while in Canada,and when i got home realised it only had ethernet in for the internet,whereas im on ADSL,so i just use it as an extension of my wired router,which i kept hold of.

Works fine and dandy.