Most systems with an MTS 493 or 494 series controller use a crossover cable to connect the controller PC to the controller. If a straight-through (normal) network cable is used, the PC will not be able to communicate with the controller. The only time this is not true is when the system is using a legacy TestStar IIs controller or has the “PC per Station” option installed. "PC per Station" is an optional add on to the system that will allows the use of up to (4) PCs to control multiple stations on a single controller. An easy way to tell if this is installed is that the controller PC will have a network hub installed between it and the controller.
If the controller PC is connected directly to the controller, and you are not using a TestStar IIs controller, then you will need to use a crossover cable to facilitate the controller to PC connection.
Crossover cables are normally marked as such, but at times they may not be.
Here is a short video to help you to correctly tell a crossover cable from a normal network cable:
Normal Cable Pinout:
Crossover Cable Pinout: