USB to RS232 Converter

Features include ...

Converts a USB port into an RS232 port
Powered entirely from USB port
Up to 250kbps RS232 data rate
For Windows 98, ME, Win2000, WinXP, Vista, Win7
Apple Mac O/S supported (check before purchase)
Female screwlocks on RS232 - like a standard PC RS232 port
All standard PC RS232 handshake lines supported
Compatible with KK Systems RS232-422/485 converters
Very low cost

The USB232 is a non-isolated USB-RS232 converter. Drivers are included (on a 80mm CD) to create a virtual COM port in the operating system. This product is ideal for laptops which do not have a serial port, or where an extra serial port is required. For RS422 or RS485 ports, use the USB485.

(the above PDF incorrectly states the maximum data rate as 1mbit/sec - 250k is the correct figure)