A serial interface is a communication path that sends data one bit at a time over a single channel or wire pair, rather than many bits in parallel. Common examples include UART, RS-232, and device console links. Because the data rate is usually low and the protocol is simple, serial links are widely used in embedded devices, legacy systems, and hardware debugging.
In cyber security, serial interfaces matter because they often expose direct device control, boot messages, configuration menus, or firmware update paths. Attackers may abuse an unprotected console to gain access, change settings, or extract secrets from hardware. Defenders use serial links for diagnostics, incident response, and recovery, but they also secure them with physical access controls, authentication, and careful parsing. In projects like an NES showing flight data, the serial channel is the narrow bridge that moves modern information into constrained hardware, so its format, timing, and trust assumptions become critical.