The OM-CONV-USB from Omega Engineering Inc., Stamford, CT, is an RS-232 to USB interface converter. The device includes driver software, has a >1 Mbps data transfer rate, and is powered from the USB cable. You can install the driver software on to the PC, connect the converter into the USB port, and the system will recognize the device. You can then connect the converter to a serial device.
Serial to USB Interface Converter from Omega
Omega Engineering Inc.