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 and management software), dimming controllers, dimmable luminaires, outdoor luminance detection devices, and a fiber optic transmission system. The outdoor luminance detector transmits the detected luminance signal outside the tunnel to the entrance-section dimming controller, which then uploads it to the control computer. After performing logical calculations on the collected outdoor luminance, the control computer determines the currently required luminance level and issues dimming commands to each dimming controller. The dimming controller converts the required luminance 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 at the tunnel site through the fiber optic transmission switching network. Different dimming controllers are distinguished by addresses. The dimming controllers and LED luminaires use DC 1-10V analog voltage for dimming. 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 at the tunnel 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 inside 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 can be installed inside the tunnel and at entrances/exits to enable emergency broadcast and evacuation functions when handling emergencies. **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 is installed in the tunnel monitoring room, and multiple access-type optical transmission devices IDMGTD442 are installed at the tunnel entrance, exit, and on both sides inside the tunnel. Each access-type optical transmission device IDM GTD442 can provide 2 Gigabit Ethernet interfaces, 2 audio interfaces, and 2 RS485 interfaces, which can be used to connect HD network cameras, emergency broadcast terminals, and multiple dimming controllers in 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, emergency call, and other functions. Additionally, a multimedia [dispatch switch](/product/) can be deployed to provide one-key direct emergency dispatch functions for emergency telephones and intercoms installed in the tunnel. **3**           **Solution Features** 1) The equipment selected in this system has the capability to form chain networks and ring networks in terms of networking. This simplifies cable installation and, in the event of an optical cable interruption at a certain location, the self-healing ring network can ensure 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 can also provide corresponding access means for security surveillance and emergency communication after future expansion.