Siemens 6GK1503-2CA01 is the SIMATIC NET PROFIBUS OLM/P11 V4.1 optical link module. It combines an RS-485 electrical interface with a plastic-fiber optical interface. The optical channel uses separate transmit and receive BFOC sockets. Suitable POF or PCF fiber connects the module to the matching optical network endpoint. A signaling contact and measuring output support link supervision.