If a lot of red light is visible, the connector is bad and should be replaced. OTDRs can determine the bad connector if the cable is. Why can the red LED light be seen from the DIGITAL OUT (OPTICAL) terminal? The red LED light can be seen from DIGITAL OUT (OPTICAL) when the Digital Audio Connector Adapter is inserted to the TV without an optical cable connected. Mishandling, such as improper plugging, poor storage, and dirty connectors, can damage optical cables. Proper cable care includes gentle handling. That's the optical receiver for your probe/ tool setter, probably renishaw. Thats the camera your boss records your crashes on so they can be brought up as evidence when they deny your raise at your review Probe transmitter/receiver its the receiver for the tool setter and. Is the red light coming from the optical audio port on the back of my TV an eye damaging laser or an LED and is it safe to see and/or look at? Is the red light coming from the optical audio port on the back of my TV an eye damaging laser or an LED and is it safe to see and/or look at? According to. Red optical light on the ONT means there's no light signal from the fiber. You'll need a tech out to get it fixed, unfortunately. Thank you I think there is some wide outage going on in the bay area. Nope, only fix is to switch ISP's. Frontier. If you find that the Optical/Config/PON Light on your Fibre ONT (Optical Network Terminal) box is flashing, has gone off, or has gone red, this indicates there may be an issue with the fibre connection coming into your property.