Each field type has a set of allowed picture control characters. Only the allowed picture control characters are recognized by the system. All other characters, including those that are system picture control characters, act as protected characters in a field.
For instance, the allowed picture control characters for Boolean fields are A, X, Z, *, and !. If you use the pound character (#) in a Boolean picture string, this character will be considered a protected character even though it is a system picture control character.
When a form is displayed, the protected characters are printed in the data field and protected, that is, the cursor will skip over the positions they occupy in a field. In the following picture for a phone number
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the cursor would skip over the parentheses and the hyphen when entering the phone number. Because protected characters cannot be changed by the user, the protected characters will always appear in the data field.
Protected characters are not allowed in numeric fields except for (1) an E when defining a picture for entering a number in scientific notation for a floating point field and (2) a hard decimal separator character in decimal or floating point fields.
Table 7.2: Picture Control Characters
| Picture Control Character |
Allowed Characters for Data Entry |
| A | Alphabetic characters (letters) and spaces only |
| X | Any printable text characters and symbols |
| Z | All character codes (including graphics and non-printable characters) from 0 to 255 |
| ! | Any printable character; converts lowercase letters to uppercase before printing them in the field |
| * | Any printable character; converts uppercase letters to lowercase before printing them in the field |
| U | Digits 0 through 9 (unsigned integers) and spaces |
| 9 | Digits 0 through 9, + , -, and spaces |
| # | Digits 0 through 9, +, - , system decimal separator, spaces, and an E (exponent indicator for scientific notation) |
| @ | Places decimal separator |
