DCF77 is a long-wave time signal transmitter operated by Germany’s national metrology institute (PTB), broadcasting from Mainflingen near Frankfurt on 77.5 kHz. It transmits the official German time (UTC+1 or UTC+2 during summer).
In information security, DCF77 plays a role in time synchronization for physical systems such as access control panels, time-recording terminals, and alarm systems. Accurate timestamps are fundamental for logging, forensic analysis, and correlating security events. For IT systems, NTP is generally preferred, while DCF77 serves as a fallback or for devices without network connectivity.