I am using an old PLC to generate a signal to a display. I must use rs232 from my PLC and then convert it to rs422. I am using a converter to change the signal but I cannot get the display to work. The PLC is sending the right signal (I have captured it on a laptop) but it isn't getting to the display. I have used a laptop to send the signal and it works but not when the PLC is pluged into the circuit. I was wondering if anyone has seen such an issue? I was thinking of putting a 232 booster inline but I am only using 2 feet of cable fromt he PLC to the converter. Is a booster still needed?