USB Alternative
Parallel Ports
Parallel ports are a legacy computer interface used mainly for printers and older peripherals, with specialized modes for bidirectional device communication.
Overview · Comparison to USB · Use cases · Articles
Related: Serial Ports · SCSI · PS/2
Parallel port overview
Review the PC parallel port and IEEE 1284 interface, including its printer-focused origins, bidirectional modes, common connector, typical peripherals, and legacy status.
| Primary purpose | Legacy printer and peripheral communication |
|---|---|
| Standard family | IEEE 1284 parallel peripheral interface |
| Common PC connector | 25-pin D-sub connector on many PCs |
| Communication | Parallel, with bidirectional operation defined by IEEE 1284 |
| Typical devices | Printers, scanners, storage devices, dongles, and specialized equipment |
| General-purpose modern bus | No |
| Current status | Legacy; IEEE 1284-2000 is inactive-reserved |
Sources: IEEE 1284-2000 and Intel workstation parallel-port documentation.
Parallel port comparison to USB
Compare parallel ports with USB for printer and peripheral connections, bidirectional communication, connectors, hot plugging, device range, and modern adapter use.
| Factor | Parallel port | USB |
|---|---|---|
| Primary role | Legacy printer and peripheral interface | General-purpose peripheral bus |
| Data model | Parallel signaling with IEEE 1284 bidirectional modes | Serial USB protocol across modern USB links |
| Typical devices | Older printers, scanners, dongles, and specialized hardware | Printers, storage, input devices, audio, cameras, networking, and many other peripherals |
| Hot plugging | Not built around the modern USB plug-and-play model | Designed for plug-and-play peripheral attachment |
| USB relationship | Some legacy printers can be connected through compatible USB-to-parallel adapters | Provides the modern host connection for many adapter cables |
| Best fit | Existing equipment that specifically requires a parallel interface | Modern printers and general peripherals |
Sources: IEEE 1284-2000 and USB-IF USB4.
Parallel port use cases
See where parallel ports still matter for legacy printers, specialized hardware, dongles, and installed systems, and when USB or network connectivity is the better option.
| Use case | Why parallel fits | Better modern option |
|---|---|---|
| Legacy printer | The printer may rely on an IEEE 1284-compatible parallel interface | USB-to-parallel adapter when compatible, or a newer USB/network printer |
| Industrial or specialized equipment | Long-lived hardware may require direct parallel-port signaling | Keep the native interface where adapter behavior is insufficient |
| Hardware dongle | Some older licensed software or equipment used parallel-port security devices | Use the vendor-supported migration path where available |
| Older desktop PC | Native parallel hardware may still support existing peripherals directly | USB or network peripherals during normal hardware replacement |
| New printer setup | Parallel offers little benefit for new equipment | USB, Ethernet, or Wi-Fi depending on the printer and sharing needs |
Sources: IEEE 1284-2000.
Parallel port articles
Explore guides about USB and parallel-port compatibility, legacy peripherals, adapter limitations, troubleshooting, and older hardware connections.
