DWDM Long Haul Transmission Network Solution | FS 

Many thanks!

Hi Sanjay khatri, since DWDM multiplexer or demultiplexer is a passive device and needs no electrical power so there might be two situations depending on the OTDR type you are using. If you are using a handheld OTDR tool, you may need to shut down the link and connect the OTDR to the point you want to check (like unplugging the patch cord from the transceiver or adapter); if you are using a line card OTDR that was inserted in a management chassis, you may check the device info from the management software and there's no need to stop the link.