ethernet sharing

[Larry]

I have an ethernet cable from my ibook to my speedtouch 510 modem, and I also have an ethernet connection from my imac to the 510 modem. So can I then send data from my ibook to my imac through this connetion? Or do I need just to place another ethernet  cable between them? And then how do I allow sharing between them, without leading myself open to an intruder?

[kelly]

Hi Larry. Not familiar with that device.  

Is it this one?

http://www.adslguide.org.uk/hardware/revie.../q4/st510v4.asp

There's a link there to a pdf file if it is.