What cable do i need?



Hi i was wondering what cable i could use to get digital output from my normal laptop Soundcard. Its got the normal analogue line out that all cards have but i have a decoder which accepts both Optical and Coaxial SPDIF inputs, so i was basically wondering is there a cable i can buy which could convert the data coming out of my soundcard into one which would be accepted by the digital inputs of my decoder, Analogue->Coaxial cable of some sort?

I have windows XP home
a Realtek AC97 Soundcard
Videologic digitheatre Decoder

am very thankful in advance for your help!