As explained earlier in this article, a Prolific USB-to-Serial adapter cable is used to connect the devices with a serial port, like a PLC (Programmable Logic Controller) with a computer. You need to connect a PLC with your computer via a USB-to-Serial adapter cable for writing the program into the PLC. You can use the Prolific USB-to-Serial adapter cable or a USB-to-Serial adapter cable of any make for this purpose.