ADSL modem router als "einfache" router?

I have a cable modem connection (UPC) and would like to connect more than 1 computer. I have a Netgear DG814 ADSL modem router, which I used to use when I had an ADSL connection in the past. This has a 4-port router and a number of options (e.g. I can set the MAC address via the web interface).

Is it theoretically possible to use this device as a router behind the cable modem? I tried but couldn't set it up yet (I've set the MAC addres but it only worked with the first - original - computer, the 2nd one I couldn't connect to the internet).

UPC socket -----> cable modem -----> ADSL modem router -----> multiple PC's (max. 3 as the router has 4 ports)

Here's a description of the DG814:

http://www.adslguide.org.uk/hardwar...tgear-dg814.asp

I know that I could get a router as cheap as EUR 20 but thought I try to recycle this device before throwing it out.

Any advice would be apprecaited! (Antworte in Deutsch kein Problem)
Many thanks,
puffin789

(I've read about the possible implications of connecting multiple pc's to UPC - here I don't need advice on that but rather on this specific technical issue.)

Thanks very much, I've got a router and all is set up and working!