The MR-DIO-1 module has 6 universal contacts. Each of the contacts, depending on how it is connected, can be a digital input or output. The digital input, treated as a "potential-free contact", is implemented by closing the circuit of this input to the "minus" of the module supply voltage. The digital output, treated as an "open collector", is realized by closing the circuit of this output to the "plus" of the module supply voltage. The module has the function of saving the state of outputs in non-volatile local memory. Each time the module power is turned on, the outputs will be restored to the saved state. Reading the status of contacts or setting their status is carried out through the RS485 port using the MODBUS RTU communication protocol. All communication and data exchange parameters are factory set. The exception is the module's network address, which is set with a multi-position switch located under the front panel of the module. Turning on the supply voltage is indicated by the green U LED. Correct data exchange between the module and the other device is indicated by the yellow Tx LED.