Maybe a BT engineer will have come across this before?

How on earth can my phone receive incoming calls yet not manage to connect outgoing attempts?
More importantly, how do I fix this?

Phone was fine before I fitted wireless equipment, and if I disconnect the power lead to the router I can call out.

Belkin ADSL Modem with wireless G router located where line enters the house. Belkin wireless and USB network adapter, on the Computer.

Broadband connection appears to be unaffected by phone use. Though I have noticed I'm getting a lot of "connection refused" error messages which stop if I persist trying to connect. Never got them before I wirelessed.

Thanks for any input possible.