In scenarios where the interface of one device does not match the interface of the other device, interface converters are used. They are often also called converters or device servers. They convert from one interface or fieldbus to another interface or fieldbus. Device servers are used when integrating serial devices into an Ethernet network.
The essential tasks of a interface converter are:
1. Converting the plug connection so that the device/bus connections with their plugs and sockets fit from both sides.
2. Providing the prescribed electrical levels of all cable lines on both interfaces.
3. Converting the data from one protocol to the other - and vice versa.
If it is a simple 1:1 bit or byte mapping, the converters are plugged in and function according to the plug-and-play principle. If the structure of the data frames on the two interfaces is very different, the user must still configure or even programme the interface converter.
Device servers can simultaneously support several serial devices on one IP address (e.g. 2, 4 or 8). The devices can then either all be mapped to one PC as COM3, COM4, ... COM10 or each can be addressed by different PCs, servers or PLCs. With the help of this hardware and software technology, device servers integrate existing serial devices and machines very closely into the modern concepts of digitalisation and Industry 4.0.