KEYSPAN 4PT USB SER ADPT ROHS The USB 4-Port Serial Adapter makes it easy to connect four RS-232 serial devices to a USB port on a PC or Mac. Linux is not currently supported. This adapter is ideal for industrial and enterprise markets where there is a need to connect serial devices to a PC for process control, data collection, or point of sale applications. It is also ideal for connecting modems, fax modems, or terminals to a server.