The cables must meet the stringent flame-resistance and/or smoke generation requirements of the National Electrical Code® (NEC®) and local building codes, dependent upon their installed location and be marked for the intended application as OFN/OFC (general purpose) . The cables must meet the stringent flame-resistance and/or smoke generation requirements of the National Electrical Code® (NEC®) and local building codes, dependent upon their installed location and be marked for the intended application as OFN/OFC (general purpose) . This entry describes the various possible combinations and necessary properties of devices, cables, etc. that are used for an optical PROFINET connection in hazardous areas, in particular to an ET200iSP station or similarly suitable peripheral stations in explosion protection zones 1 or 21. ITU-T has been active in the standardization of optical communications technology and the techniques for its optimal application within networks from the infancy of this industry. However, it is not always easy to find out what has been covered, and where it can be found. This manual attempts to. The Fiber Optic Association, Inc. During installation, all curvatures should be smooth. The primary considerations in selecting an appropriate cable design are the installation method, the environment (including the. Adherence to safety protocols is crucial during the installation of fiber optic cables and network infrastructure in the European Union.