Sarjaliitäntöjä

Sarjaliitäntöjä, known in English as serial ports, are interfaces that enable the transmission of data one bit at a time. This is in contrast to parallel ports, which transmit multiple bits simultaneously. Historically, sarjaliitäntöjä were a common feature on personal computers for connecting peripherals such as modems, mice, printers, and terminals.

The most prevalent type of sarjaliitäntöjä was the RS-232 standard. This standard defined electrical characteristics, signal timing, and connector types, typically using DB-9 or DB-25 connectors. Data is sent sequentially over a single wire or a pair of wires, with additional wires used for control signals like request-to-send (RTS) and clear-to-send (CTS).

While less common on modern consumer devices, sarjaliitäntöjä remain important in industrial automation, embedded systems, and for specialized equipment where their simplicity, reliability, and long-distance communication capabilities are advantageous. Many network devices like routers and switches still feature console ports that use serial communication for configuration and management.

The decline in their use on mainstream PCs is largely due to the rise of faster and more versatile interfaces like USB (Universal Serial Bus). USB offers higher data transfer rates, plug-and-play functionality, and the ability to power devices, making it a more convenient choice for most consumer peripherals. However, the fundamental concept of serial communication endures in many modern technologies, including Ethernet and USB itself, albeit implemented through different protocols and hardware.