An optical communication interface module includes a combined transmission module and a combined reception module. The combined transmission module processes a D+ electrical data signal and a D- electrical data signal, and combines and transmits the same through a first optical fiber line. The combined reception module processes the D+ and D- electrical data signals combined and received through a second optical fiber line, and applies the D+ and D- electrical data signals to a D+ port and D- port, respectively. The combined transmission module includes a transmission driving circuit that generates an optical data signal corresponding to one of the D+ and D- electrical data signals, and a transmission control switch that controls the optical data signal to have a level of brightness higher than a first set value while the D+ and D- electrical data signals are both maintained at a logic 'low' state, and controls the transmission driving circuit.