Sigma EF-500 ST don't work with 20D

[ranch]

Hi,
I have Canon 20D and I'm trying to use the EF-500 ST I have from my old SLR (not digital) camera but it doesn't work.
I thought that maybe it is incompatible with digital camera but it's just a guess.

I hope you can help me fix it, and save me the money of buying a new flash.

Thanks
Rani

[Curtis N]

If you don't find a "DG" in the model number, then it's not compatible with digital cameras.

Sorry.