| Bit position | Meaning | Values |
|---|---|---|
| 0–1 | Field attribute byte | Both set to 1 |
| 2 | Unprotected/protected |
0 = Unprotected data field
1 = Protected data field
|
| 3 | Alpha/numeric |
0 = Alphanumeric data
1 = Numeric data only
|
| 4–5 | I/SP |
00 = Normal intensity, pen not detectable
01 = Normal intensity, pen detectable
10 = High intensity, pen detectable
11 = Non-display, pen not detectable
|
| 6 | Reserved | |
| 7 | MDT (Modified Data Tag) |
0 = Field has not been modified
1 = Field has been modified
|
| Bit position | Meaning | Values |
|---|---|---|
| 0 | Field attribute flag |
0 = Not a field attribute
1 = Field attribute byte
|
| 1 | Visibility |
0 = Non-display
1 = Display
|
| 2 | Unprotected/Protected |
0 = Unprotected data field
1 = Protected data field
|
| 3 | Intensity |
0 = Normal
1 = High
|
| 4–6 | Field type |
000 = Alphanumeric: all characters allowed
001 = Alphabetic only
010 = Numeric shift: automatic shift for numerics
011 = Numeric only
100 = Reserved
101 = Digits:
110 = Magnetic stripe reader data only
111 = Signed Numeric
|
| 7 | MDT (Modified Data Tag) |
0 = Field has not been modified
1 = Field has been modified
|