If you bought a PTZ camera and you realized that you need to have a RS485 connection to your PC (if you are going with a PC based DVR) and you do not have a serial port on your computer to fit that nice RS485 to RS232 adapter that you just bought to, then you need a new computer, motherboard, or this new RS485 PCI card for you PC. Pending you have an extra PCI expansion slot on your computer's motherboard, you can connect this to the board and open up a way for your computer to send and receive data to your PTZ camera. See without the RS485 connection your security dvr cannot instruct the PTZ camera. Not too many online stores carry this part, however, we do! We will be adding a new menu to the site titled "PTZ Camera accessories". You can find it in our CCTV accessories menu or under the PTZ security camera's sub menu. We have them priced for only $80.