Fehlsignal

Fehlsignal is a German term that translates literally to “error signal” or “fault signal.” In technical contexts, it denotes a signal that does not correctly represent the intended state or information. The concept appears in several fields, most notably in railway signalling, telecommunications, and industrial control systems.

In railway signalling, a Fehlsignal arises when a signal device displays an incorrect aspect, such as a green light when a danger aspect is required, or when a switch fails to lock in the intended position and the associated signal fails to reflect this. The phenomenon can lead to dangerous situations if trains continue under the wrong visual cue. Railway authorities often classify Fehlsignale as “critical faults” and require immediate inspection, repair, or replacement to restore safety integrity. Modern signalling systems employ redundancy and diagnostic checks to detect and isolate such faults quickly.

Telecommunications and digital electronics use the term to refer to erroneous data packets, corrupted frames, or corrupted bitstreams that result from noise, hardware faults, or software bugs. Error detection codes—such as parity bits, CRCs, and checksums—are designed to flag Fehlsignale so that upper-layer protocols can request retransmission or error correction.

In industrial control, a Fehlsignal may refer to a false alarm triggered by faulty sensors or misconfigured actuators, potentially causing unnecessary stopping of processes or triggering of safety interlocks. Preventive maintenance, calibration, and system health monitoring are employed to mitigate these faults.

Across all domains, the identification and correction of Fehlsignale are essential for maintaining operational reliability, safety, and quality of service.