From the late 1980s to the early 2000s, portable computers used physical interfaces called serial ports. They were also known as RS-232 connectors or COM interfaces. Peripherals like keyboards, game consoles, and modems were connected via serial interfaces. Serial connections are still utilized in integrated computers in the industrial and science sectors, despite being usually viewed as outdated in home computing since the advent of the USB port.

In contrast to parallel ports, which transfer many bits concurrently in parallel, serial port links send data one bit at a time in an unique data stream. The link is bi-directional when using a serial interface because separate ports are used to transmit and receive data. Parallel port links are faster, but serial port wires and connectors are smaller and less costly to adopt due to the easier technology.

There were many different kinds of serial port connections; the most prevalent versions were 25-pin DB-25 and 9-pin DE-9 interfaces. Apple Macintosh computers used an 8-pin Mini-DIN connector for their serial interfaces. In order to solve the flaws of the earlier standards, the Universal Serial Bus (USB) standard was introduced in the late 1990s to supplant the different serial interfaces as well as the parallel port. It provided faster rates, plug-and-play functionality, and the capacity to give devices more power.

Serial Ports Today

Serial connections are no longer used in desktop computers, but they are still widely used in other environments. On tiny, low-power gadgets with particular purposes, serial connections are easy, dependable, and affordable to install. A straightforward physical link that transmits tiny quantities of data is all that is needed in many specialty devices, including industrial processors and medical equipment. They are frequently still in use merely because a device was created in an era when serial connections were widespread, is still reliable, and doesn't need to be redesigned and replaced.

Serial connections are still used by science and industrial robotic devices to communicate with computers and share data and setup settings. Large-scale networking devices also often employs serial interfaces for troubleshooting and setup links. Administrators can link to these devices using a USB-to-serial converter instead of changing out otherwise dependable equipment just to adopt a modern interface.