foutbits

Foutbits are bits used to indicate the presence of errors or faults within a data unit, channel, or subsystem. The term appears in some Dutch-language and English technical documentation as a shorthand for fault or error status indicators. Unlike data bits, which carry payload information, foutbits serve as flags that help diagnose, report, and potentially correct problems in hardware or software systems.

Implementation varies: a foutbit may be a dedicated bit within a status word, part of a separate error byte, or embedded in a frame's flag field. In practice, foutbits are set when a validation check fails (such as a parity check, CRC, or ECC), or when a component reports a fault condition. They may be used alone to signal a fault, or combined into multi-bit codes that classify error types.

In operation, foutbits guide recovery actions such as retransmission, retries, or failover, and they enable error logging and diagnostic tracing. The precise semantics depend on the system design; a "fault" could reflect a minor, recoverable condition or a critical failure that requires hardware replacement or system shutdown.

Because foutbits are not a universal standard term, many contexts refer to equivalent concepts as error bits, fault flags, or status bits. Understanding their meaning requires consulting the relevant specification or documentation for the particular device or protocol.