- *: Format excluded 2 letter aplha prefix
- 9: A digit
- X: A letter or a digit
- S: A letter; a digit; "+" or "*"
- L: A letter (NL)
- 1: The 1st position following the prefix is always "U".
- 2: The first digit following the prefix is always zero ('0').
- 3: The (new) 10-digit format is the result of adding a leading zero to the (old) 9-digit format.
- 4: The first and last characters may be alpha or numeric; but they may not both be numeric.
- 5: Identifies branch traders.
- 6: Identifies Government Departments.
- 7: Identifies Health Authorities.
- 8: The 10th position following the prefix is always "B". (NL)