TD System Card TD System Card makes it easy to provide input and output signals to a CNC machine. The provided card is manufactured using top quality components with the aid of advanced machines by diligent experts. We offer this card for Computer numerical control(CNC). This card is used in computer numerical control for controlling input or output signals and functions. Known for its high quality and easy installation, the offered TD System Card is can be categorized as storage, communications or user-interface card.