BS 6541:1985

National foreword
Committees responsible
Specification
0 Introduction
1 Scope and field of application
Section one: General
2 Definitions
3 Types of systems
4 Compliance and designation
Section two: Pure systems
5 Specification of pure systems
6 Computational methods for pure systems with one check
   character
7 Computational methods for pure systems with two check
   characters
Section three: Hybrid systems
8 Specification for hybrid systems
9 Computational method for hybrid systems
Annexes
A Criteria for the selection of check character systems
   for applications
B Check character systems for other alphabets
Tables
1 Pure systems
2 Hybrid systems
3 Values assigned to characters
4 Pure system weights
5 Summary of criteria for selection of systems

Describes 8 check character systems capable of protecting strings against errors that occur when people copy or key data; includes conformance requirements for products described as generating check characters or checking strings using those systems; includes guidance on selection of check character systems for application. Excludes systems designed specifically to permit both error detection and automatic correction, to detect fraud, to check strings interchanged only between machines.