8.6.2 Field Prefix Character
Mandatory.
Specify the character to be used as the field prefix character in LANSA. This character is normally the # character.
For example, the Standard Name field in the repository is identified as #STD_NAME. The # symbol allows LANSA to identify this as a field name in RDML commands.
Note: Do not change this character unless you are absolutely sure that the field prefix character needs to be changed as the result of character translation issues. On the IBM i, this character must be set up to be translated to and from the HEX 7B character in the translation tables.
Also See
8.6.3 Substitution Character for the @ Character