I have the Hexa Decimal input and need to convert it into its corresponding Decimal value & ASCII Value. I am interpreting the input hex value as "Character" i.e. Item Subclass is 'Text' & Interpret as 'Character'.
If your type tree is defined correctly you should be able to simply point the new field at the old field and run your map. Your output will be in the format you require.
I think you should read the input field as binary and it could either be float or packed decimal depending on how the source created it (mainframe I assume) then to convert it into ascii you will need HEXTEXTTOSTREAM function. I hope this will help.