Conventional Numerical Controllers (NC) use a process defined by instructions typed on cards that are read sequentially by an external card reader. But the process is not very flexible—when the manufacturing process changes, it is necessary to make an entirely new set of cards. Alternatively, the control process can be input from tapes, but because of the limited speed of the tape reader and the manual operations that are required, this is still not fast enough, and is not suitable when multiple NCs operate concurrently. What is needed is a fully automatic operation.

The modern NC is equipped with a computer communication interface (normally a serial port) that makes Computerized Numerical Controllers (CNCs) easy and flexible to use. The company mentioned here uses a PC running Windows 95 that is installed with MOXA C320Turbo. Not only can the C320Turbo control up to 32 FANUC CNC machines at the same time via a high-speed communication interface (460.8 Kbps max.), it can also swiftly transmit massive amounts of CAD/CAM data to 32 CNC machines simultaneously. The company greatly appreciates C320Turbo's expandability, allowing external serial modules to be located as far as 100 m from the C320Turbo control board, which connects to the PC. This feature not only simplifies layout, but also reduces cost.