sed - replace with octal/hex character

[WildingLS]

I have used tr to replace characters with an octal characters e.g. tr ',' '\043'
BUT
How do I use sed to do the same?

sed 's/,/\043/g' in > out

or

sed 's/,/\x23/g' in > out

This does not work for me.
Is it just a syntax error or is it the version of sed I use does not support conversion from to octal?

Any help apreciated.

 

[WildingLS]

I have found out how to do it....e.g.

'/s/0/'`echo "\043"`'/'