Calling a Skype user from a standard SIP phone

[Hades]

A friend in Sweden has a Skype phone. My router (Draytek Vigor 2800VG)allows me to connect a normal phone and converts it into a standard SIP VOIP phone. Would this allow me to call Skype for free? Or are the two systems incompatible?

Thanks.

 

[Hades]

Thanks. I don't really want to buy a Skype phone because that defeats the point of saving money. It would be cheaper to carry on calling using a normal phone (for a while at least). But thanks for the answers.