This USB (Universal Serial Bus) to Serial Converter means that you can connect up to 4 serial devices to a single USB (Universal Serial Bus) port. The compact size & USB (Universal Serial Bus) bus-powered design make it ideal to be used with notebooks or as an alternative to installing an internal serial card in your desktop PC. It supports most standard RS-232 serial devices such as modems, PDAs, barcode readers, label printers, EPOS devices etc.