Is an element in a closed system for data processing, which has the function to enable data to leave the system or to read data into the system.

Here the term is used to indicate whether a machine control is able to read data from an external source without entering it via keyboard.

This can be done directly or indirectly:

Direct data transmission

In a direct data transmission the machine control and the data source are linked directly. This is usually done by means of a cable, in this case the socket in the control represents the data interface. In woodworking machinery, there are often interfaces for the following direct data transmission:

• RS232 (parallel port, once a widespread printer port, becoming obsolete)
• 8P8C Ethernet, better known as RJ45 which actually is the plug standard (the most commonly used interface for direct data transfer, wired network)
• USB (this interface is, however, more often used for indirect data transmission)
• Wireless LAN (due to the vulnerability of wireless networks this is still rare in machine controls)

Often in older machines with obsolete interfaces a solution can be found where the machine is connected to a seperate PC, which in turn is connected to the corporate network. Especially with controls, which do not contain a standard PC this is the only way to allow direct data transmission.

Modern control systems, especially in CNC-machining centres usually contain a standard PC, so the connection via an Ethernet interface today is no problem at all.

Indirect data transmission

One type of data interface can be data readers. There is no direct transfer of data from data source to control, but the data is temporarily saved on a medium, brought to the control and read by means of a suitable data reading device. In controls of wood processing machines the following devices are commonly used for indirect data transmission:

• Floppy disk (or floppy drive, becoming obsolete)
• CD-ROM drive / burner
• USB (because of the ease of use this at present probably is the most widespread variant. Very rarely, it is used for connecting by cable and directly transmitting data)
• Card reader (used rarely, mostly integrated in machinery with standard PC)