DIN EN 61753-042-2:2015-06

This standard contains the minimum initial performance, test and measurement requirements and severities which plug-pigtail style and plug-receptacle style OTDR reflecting devices need to satisfy in order to be categorised as meeting the requirements of category C-Controlled environments, as defined in Annex A of IEC 61753-1. They are used when monitoring optical fibres transmitting communication lights, and are optical filters that allow the communication light to pass but cut off the test light in front of optical network terminals are installed.