Integrated Fiber Optic Communication System for Tunnel Emergency Lighting/Security Surveillance/Emergency Command System

**1** **Requirements Analysis** **1.1** **Dimming Control** The lighting control transmission system in a certain tunnel consists of a control computer (monitoring management software), dimming controllers, dimmable luminaires, external brightness detection devices, and a fiber optic transmission system. The external brightness detector transmits the detected brightness signal outside the tunnel portal to the entrance-section dimming controller, which then uploads it to the control computer. After performing logical calculations on the collected external brightness data, the control computer determines the required brightness level and issues dimming commands to each dimming controller. The dimming controller converts the required brightness level into a DC 1-10V analog signal output to control the voltage-controlled current source on the LED luminaires (output-current-controllable LED driver), thereby achieving the function of adjusting luminaire brightness. The control computer can be placed in the tunnel monitoring room and exchanges data with the dimming controllers on site through the fiber optic transmission switching network. Different dimming controllers are distinguished by addresses. Dimming between the dimming controller and LED luminaires is achieved via DC 1-10V analog voltage. The control computer can also be placed in the road monitoring center, connected to the tunnel fiber optic transmission switching network via the IP transmission network, to exchange data with the dimming controllers on site. **1.2** **Security Surveillance** HD network cameras can be installed inside the tunnel and at the entrances/exits for real-time monitoring of vehicle operation status within the tunnel and timely recording of video evidence during emergencies. The network cameras transmit data through the fiber optic transmission system. **1.3** **Emergency [Command & Dispatch](/solution/)** Amplification equipment is installed inside the tunnel and at entrances/exits to enable emergency broadcasting and evacuation functions when handling unexpected incidents. **2** **Solution Design** Based on the requirements analysis, the system design is as follows: In this solution, the basic transmission adopts a 2.5G fiber optic chain network. An aggregation-type optical transmission device [IDMMSAP-G3CP](/product/) is installed in the tunnel monitoring room, and multiple access-type optical transmission devices IDMGTD442 are installed at the tunnel portal, tunnel end, and on both sides within the tunnel. Each access-type optical transmission device IDM GTD442 provides 2 Gigabit Ethernet interfaces, 2 audio interfaces, and 2 RS485 interfaces, which can respectively connect HD network cameras, emergency broadcast terminals, and multiple dimming controllers within the tunnel. The aggregation-type optical transmission device IDM MSAP-G3CP in the tunnel monitoring room implements aggregation and switching functions for network, audio, and RS485 data. A broadcast control host from our company can be installed in the monitoring room to provide real-time group management of emergency broadcast terminals installed in the tunnel, audio source selection and playback, and emergency call functions. Additionally, a multimedia [dispatch switch](/product/) can be deployed to provide one-key direct emergency dispatch functions for emergency telephones and intercoms installed within the tunnel. **3** **Solution Features** 1) The equipment selected in this system supports the capability of forming chain networks and ring networks in networking. This simplifies cable installation and, in the event of an optical cable interruption at a certain location, the self-healing ring network ensures uninterrupted service transmission. 2) The central-end equipment has the capability to aggregate multiple RS485 services into one IP port and to aggregate Ethernet services. 3) It also provides corresponding access means for security surveillance and emergency communication after future capacity expansion.