You have successfully added from to your part list.
USB to RS232 Serial Converter
USB to Serial Converter This cable converts USB Signals to RS-232 signals, allowing serial devices such as modems and POS systems to work in a USB environment. In situations where serial devices must be connected to the PC host, this cable allows the devices to connect to the PC's USB port, freeing the few COM ports available on your PC for use in other applications like data acquisition, PLC monitoring and instrument control.
USB (Universal Serial Bus) Rev. 1.1 compliant (or higher)
Supports RS-232 serial interface
Serial Transmission of up to 230400 bps
Supports Windows™ 2000/XP/Server 2003/Vista
IBM™ compatible 486DX4-100 MHz or higher
Available USB port
Windows™ 2000/XP/Server 2003/Vista
USB peripherals can connect either to a computer's port or to a hub.
If the computer doesn't have enough ports for all the peripherals, a hub is necessary.
Maximum length on individual cables is 5 Meters.
No terminators are needed on this bus.
The A (flat) type port would be considered the "out" port on a computer or hub.
The B (square) type port would be considered an "in" port on hubs or peripherals.
A typical USB "out" (Type-A) port can provide up to 500mA.
The speed is 12 Megabytes per second for USB 1.1 or 480 Megabytes per second for USB 2.0, the maximum number of peripherals to a controller is 63 (hubs needed when the computer runs out of ports).