An interface adapter for controlling a track-side object of a railway installation includes an analog input from an external source and an analog output to drive an electromechanical relay circuit. A bidirectional digital communication interface communicates digital data including first digital data transmitted and second digital data received. An analog-to-digital converter coupled to the analog input is configured to generate a first digital signal representing the electrical input. A digital-to-analog converter coupled to the analog output is configured to generate the electrical output in response to a second digital signal. A power supply supplies electrical power to the digital-to-analog converter. A programmable logic control circuit includes a control program configured to produce the first digital data from the first digital signal, transmit the first digital data using the digital communication interface, process the second digital data, and produce the second digital signal in response to the second digital data.