Serial and paralele ports

The Story of Serial and Parallel Ports: The Ancestors of USB

Before the universal USB ports we all know today, computers spoke through more primitive—but fascinating—channels: serial and parallel ports. These ports were the lifelines of communication between early microcomputers and their peripherals.

Parallel ports came first in the spotlight. They were designed to send multiple bits of data simultaneously, usually 8 bits at a time, which made them fast for their era. Printers became their iconic partners, and for years, a thick cable connected desktops to noisy dot-matrix printers. Over time, parallel ports were also used to control accessories and communication devices, especially in industrial setups. Their operation often relied on simple protocols that defined sequences of commands—almost like a language of instructions between machine and device.

Serial ports, in contrast, sent data one bit at a time. At first, they were much slower than parallel connections, but they had one major advantage: simplicity and reliability over longer distances. As technology evolved, serial ports grew faster and more versatile. They became the backbone of communication with modems, laboratory instruments, industrial machines, and even early networking solutions.

These protocols were not as user-friendly as today’s plug-and-play USB. In the beginning, they required careful configuration: port addresses, IRQs, baud rates, parity bits—settings that many early computer users had to learn and record manually. Yet this complexity also made them powerful. Engineers and hobbyists alike could program microcontrollers and minicomputers to send commands through these ports, controlling stepper motors, synchronization devices, and custom hardware.

Looking back, serial and parallel ports were not just connectors; they were the building blocks of digital communication. They taught generations of developers how machines could "talk" to each other, long before USB unified the world of computer peripherals.