ACS
[1] Access Control Store/Set (unter "ISO"/OSI VT)[2] Access Control System (->"Computer Security Basics", Russell/Gangemi, ORA 1991)
[3] Access Control Server (Cisco)
[4] Advanced Communication Service (Bell, AT&T)
[5] Advanced Communication Set
[6] Advanced Communications System
[7] Application Control Services/Set
[8] Automatic Crossconnect System
[9] Alaska Communications Systems (siehe ALASCOM)
[10] Arcus Cosinus (vergl. arccos)
[11] Australian Computer Science
[12] Assembly Contingency Subsystem (Space Shuttle) \{Weltraumfahrt\}