Just for interest's sake, it would probably cost effective to have 1 RP6 and a computer if you really need 13 RS232 control setups. With a USB HUB and a couple of USB to RS232 adapters, you could send a RS232 command from the RP6 to the computer, and have the computer do everything else...basically with a device ID as part of the command. Perhaps not practical, but it was just a thought.