ATEN US421A 4-Port USB Peripheral Sharing Switch
Overview
The ATEN US421A is a 4-port USB peripheral sharing switch that lets four computers take turns accessing a single USB device — a scanner, printer, hard drive, or other USB Type-A peripheral — without physically swapping cables. In workstation clusters, shared-peripheral lab benches, or multi-PC security workstations where a single enrollment reader or USB storage device needs to be accessible from several seats, the US421A eliminates the cable-swap workflow entirely. Port selection is handled three ways: front-panel pushbuttons for manual switching, ATEN's AP software for software-driven switching from the desktop, or Auto Switch mode that hands control to whichever computer is actively sending a signal. The unit is USB bus-powered — no wall adapter, no separate power run required.
Compatibility
The US421A connects up to four host computers via standard USB Type-A ports. AP software support is confirmed for macOS 10.10 and higher (v1.2.111, released 2023-12-07); legacy AP software builds extend compatibility back to macOS 10.6. Windows compatibility is standard for USB HID-class devices through the OS's native USB stack — no proprietary driver installation required for basic switching. The single shared device port accepts any USB Type-A peripheral. It is not a KVM switch and does not carry video, audio, or keyboard/mouse signals — it shares one USB device only.
Installation Notes
The US421A is USB bus-powered, drawing current from the connected host — ensure the host port can supply sufficient bus power before deploying with power-hungry peripherals such as external drives. Operating humidity is rated at 0–80% RH non-condensing; avoid environments with condensation risk. The unit supports rack mounting; per ATEN's published note, rack-mount product physical dimensions follow an LxWxH convention rather than the more common WxDxH format — confirm orientation against your rack plan before ordering a tray.
