Yes! Thank you SeldomSeen31!! In chatting and emailing with multiple LG support reps, none of them were able to give me that answer!Google rs232 mini jack. It looks like a 3.5mm headphone plug on one end and a standard serial cable on the other and will plug in to the "service only" port on the back of the TV.
I have now managed to get the cables that I need. However, I can't figure out what the correct serial settings should be (flow control, parity, baud rate, data bits, stop bit, crossover). Any idea? Again, I've inquired directly with LG, but no reply.