Anyone know if all the teach pendants are swappable? I have 2 with the same p/n. I is a irc4+ and the other is probably from 4+ but a bit older. The software versions are different on the screens 1.3 vs 1.4. It seems to work but if I unpush the estop I get a blank flashing screen. Possibly the estop is wired different in the robot console. I seen a older one version 4 compared to the 4+. The version 4 has a different pinout but same p/n.