Why legacy adapters matter

Technology moves fast. Interfaces that were standard a decade ago – VGA on monitors, serial ports on industrial equipment, PS/2 keyboards – are absent from modern computers. Legacy adapters bridge this gap, letting you connect older but still-functional equipment to new machines.

Legacy adapters are not just for personal use. Businesses with older industrial machinery, laboratory equipment, specialist hardware, and commercial POS systems often rely on them to keep working equipment operational without expensive replacements.

Common legacy adapter types

VGA to HDMI

VGA carries an analogue video signal. HDMI carries digital. A VGA to HDMI adapter must convert analogue to digital, which requires active electronics – not just a passive cable. Cheap passive VGA-to-HDMI cables do not work. Buy an active adapter with its own power supply or USB power input. Typical use: connecting an older monitor with only VGA to a modern laptop or PC with only HDMI.

Serial (RS-232) to USB

Serial ports (DB9, RS-232) are absent from modern PCs but remain in industrial equipment, test instruments, CNC machines, and legacy networking devices. A USB to serial adapter (typically based on the FTDI FT232 or Prolific PL2303 chipset) provides a COM port over USB. FTDI chipsets are preferred for reliability and driver support. Fake FTDI chips (common in very cheap adapters) can be blocked by official FTDI drivers on Windows.

PS/2 to USB

Older keyboards and mice used PS/2 connectors (round, 6-pin DIN). Modern PCs have only USB. A PS/2 to USB adapter is usually passive for keyboards but may need an active adapter for mice. Check the specific adapter supports your device – not all PS/2 to USB adapters handle all PS/2 protocols.

Parallel port to USB

Parallel ports were used for printers and some older peripherals. USB to parallel adapters allow older printers to work with modern computers. Compatibility is limited – many older printer drivers do not support USB-connected parallel adapters correctly. Test before deploying in a production environment.

DisplayPort and Mini DisplayPort to HDMI

Common when connecting a laptop or workstation with DisplayPort output to a monitor or projector with only HDMI. Generally passive adapters work for single-link connections. 4K at 60Hz may require an active adapter.