BONAEVER 4-port RS232 USB serial adapter bag

Four RS232 ports from one USB port

This adapter adds four serial ports to a laptop or desktop through a single USB connection, letting technicians control multiple legacy devices at once. The COM reserve function keeps port assignments fixed after every reboot, so scripts and instrument drivers never lose their target. It draws power from the USB bus, removing the need for an external supply. Supported operating systems include Windows XP, Vista, 7, 8, 10 in both 32 and 64 bit versions and OS X.

Stable operation during long sessions

Because the adapter is bus powered, it maintains consistent signalling as long as the host USB port delivers standard current, making it reliable for extended data logging or industrial monitoring. The reserved COM numbers prevent the operating system from re-enumerating ports when other USB devices are plugged or unplugged during a run. No active cooling is present, so the ABS enclosure simply radiates the modest heat generated by the UARTs. Continuous throughput stays within the limits of the RS232 specification without throttling.

ABS enclosure and fixed cable

The moulded ABS case resists knocks and chemical splashes typical of workshop benches and rack cabinets. Four DB9 male connectors sit side by side on one face, spaced for standard straight or right angle serial cables without interference. A captive USB cable terminates in a Type A plug, so there is no separate lead to misplace and the adapter stays anchored when equipment vibrates. The compact footprint lets it sit beside a laptop or mount with double sided tape inside a control panel.