mechanical security; card-key system
Refers to security systems that use mechanical or electronic means, such as card-key access, surveillance cameras, and alarm systems, rather than human guards.
This building is protected by a mechanical security system.
I work for a security systems company.
警備 is a general term for security or guarding, which can be done by people or systems. 機械警備 specifically refers to security achieved through mechanical or electronic devices.
セキュリティシステム is a broader loanword for any security system, while 機械警備 is a more specific Japanese compound often used in business contexts for automated security services.
Compound of 機械 (machine) and 警備 (security, guarding). The term likely emerged with the development of automated security technology.