Analysis of Alarm Transmission Function in Digital Optical Terminal Units

Today, a customer mentioned that they want the optical terminal equipment to have an alarm function. At that moment, I was thinking about what kind of addition would be needed to achieve this. After asking a colleague, I learned that it involves adding switch quantities to the optical terminal equipment. In the past, when working on telephone terminals, there were occasional customer requests for trigger alarm functions, but I never understood how to implement them. Today, I finally know that the alarm function comes from switch quantity optical terminal equipment.

Switch quantity optical terminal equipment can transmit alarm functions, which are mostly divided into bus-type alarms and infrared beam alarms. The function of switch quantity optical terminal equipment is to transmit infrared beam alarms. There are 2 wires for switch quantities: one ground wire and one signal wire. The wiring for positive switch quantities and negative switch quantities is the same; positive switch quantities transmit switch quantities from the front end to the back-end machine room, while negative switch quantities transmit from the back end to the front end.