connect PS2 to Dell TrueMobile 2300 router

I'm having problems connection my Playstation 2 to my Dell TrueMobile 2300 router?  It keeps saying the network cable is not connected.  My router has a flashing yellow light where I connected it.  I have two computers hooked up to the router wirelessly and those work just fine on the internet.  However the PS2 will not connect.  Has anyone had this similar problem?  Please help me get this fixed.  Thank you!