The four channel digital transmitter is part of a family of explosion protected DIN rail mounting modules that transmit to and receive from an Austdac SILBUS field bus network. The SILBUS-TX4D can transmit up to four digital on / off signals on four independent valid SILBUS channels. The four digital inputs are galvanically isolated from each other, from the power supply port and the SILBUS network port. This isolation allows the SILBUS-TX4D to provide many simple and highly effective solutions when used in installations involving intrinsically safe and non-intrinsically safe circuits.