Converting DSL modem USB port to RJ45

[mfyahya]

This isn't related to linux but i hope it's ok to ask here:
I have a DSL modem forced on me by my ISP and it only has a USB connection to my PC. So I have to leave my PC on as a gateway all the time in order to use my VoIP phone and wireless router.
Is there any way to adapt the USB port on the dsl modem to ethernet RJ45 so I can hook it up directly with my wireless router?
Will one of those USB ethernet adapters work if I connect it to the DSL modem instead of a PC?

Thanks for any help!

[heckle]

Why not just ask your ISP to swap it with a non-usb one. Or head out and grab a newer dsl modem. If you get the newer speedstreams, you can put them in bridge mode.

[mfyahya]

my ISP doesn't have a non usb one. it's the only state controlled isp in the country. customer service isn't their forte.
if i buy a new modem, i'm afraid it might be possible for them to detect it somehow and cut off my broadband connection. yes they're that evil.

Is it possible for them to find out if I swapped modems? or do all modems look the same thru the phone line?