In telecommunication, the term system integrity has the following meanings:

1. That condition of a system wherein its mandated operational and technical parameters are within the prescribed limits.

2. [The] quality of an AIS when it performs its intended function in an unimpaired manner, free from deliberate or inadvertent unauthorized manipulation of the system.

Source: From Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary