Excess-3
| Stibitz code | |
|---|---|
| Digits | 4 |
| Tracks | 4 |
| Digit values | 8 4 −2 −1 |
| Weight(s) | 1..3 |
| Continuity | No |
| Cyclic | No |
| Minimum distance | 1 |
| Maximum distance | 4 |
| Redundancy | 0.7 |
| Lexicography | 1 |
| Complement | 9 |
Excess-3, 3-excess or 10-excess-3 binary code (often abbreviated as XS-3, 3XS or X3), shifted binary or Stibitz code (after George Stibitz, who built a relay-based adding machine in 1937) is a self-complementary binary-coded decimal (BCD) code and numeral system. It is a biased representation. Excess-3 code was used on some older computers as well as in cash registers and hand-held portable electronic calculators of the 1970s, among other uses.