Citation
Abstract
This article considers codes for use in personal computer file transfer as control characters, when only upper-case ASCII can be used to avoid dependence on unique machine features and promote portability. If ten control functions are needed, a number used in at least one protocol, we seek a subset of ten upper-case ASCII characters with good distance properties. The. control functions form themselves naturally into three groups, one of two functions (ACK and NAK) and two of four. We wish to make ACK and NAK as antipodal as possible (distance 6), make the distances within each of the other groups as large as possible (4), and otherwise have as few 2's in the distance table as possible, recognizing that only even distances can occur. We find the minimum and an assignment that attains the minimum. The code is essentially unique. We also solve the analogous problem for two groups of three control functions and one group of four.
Details
- Volume
- 42-77
- Published
- May 15, 1984
- Pages
- 136–143
- File Size
- 410.4 KB