The head transmitter WT120 converts a temperature signal into a 4 to 20 mA or 20 to 4 mA standard signal. The power supply for the signal converter is provided from the current loop. The output signal is linearly proportional to the input. The signal converter can be fully configured via software before installation and is ready for operation immediately. No power supply is needed during programming via the software, as this is provided through the programming connector.