You have two different voltages for RS-485 and RS-232C. You will need to utilize a converter. Check out Black Box Company for their products. It's always a good start for communications products. Good Luck
RS485 is based differential signals where as RS232 is not. Hence You cannot directly connect the two with just a cable. You need a converter. These converters are available in the market of the shelf. It is a simple device with one or two ICs. Can even make one your self HTH Thanks
>Depending on your application, Black Box tends to range in the upper price range. I suggest you look at B&B Electronics for a variety of Communications Interface devices.