RS232 and LEDs

[prenticm]

I am fairly new at electronics beyond simple cable wiring and I am looking for the following:

I work at a production facility where on our production lines we have scale that weight each case as it goes down the line. These scales send the weight via rs232 serial printing about 50ft or so to a network client bridge where we collect these weights through the network. We have had alot of wiring issues with these serial connections and they are a pain to work on since they go around corners where you cannot see the lines to determine whether or not something is going across the scale or not. What I would like to do it add a light of some sort that signals whenever a serial print has been sent from the scale. Would this be as simple as wiring a LED inline on the transmit or would I need to do something more involved?