Digital equipment co manufactures i/o modules 900 mb which come with salient features like modbus communication, universal input/output range and an intelligent micro controller to provide flexibility with monitoring and control capabilities. The company supplies these i/o modules in a variety of analogue and discrete models which are selectable for meeting any applications. The i/o analogue input modules can convert sensor signals to digital data for transmission to the host and provide standalone local limit alarms whereas analogue output modules are useful for driving variable speed motors and positioners or send data to display and recorders. The company also provides discrete i/o modules which are applicable to monitor or control on/off, high/low and open/close devices. The i/o modules are available with a long list of standard features which make them ideal for a broad range of application.