To increase security at gas stations where city vehicles refuel, a city in Colorado wanted to install IP security cameras. These stations tend to be unmanned for most of the day and evening so installing cameras throughout the city would allow them to be safely monitored. The cameras chosen were Power over Ethernet (PoE) cameras and were to be mounted on a pole above the center island where the gas tanks were located. The central server for the station was located across the drive way, about 50 feet away. To save on installation cost, a wireless link from the cameras to the central server would be used.
System Requirements
Temperature hardened PoE switches with the following features:
- Minimum of 4 ports, 2 for the cameras, one for the access point and one for set up
- 802.3af PoE support
- -40°C to 75°C temperature
- 48VDC power input
Gigabit Ethernet media converters for link back to central office
- Support for AP, Bridge and Repeater modes of operation
- Support for WDS to allow for multiple IP streams while in Bridge mode
- 802.11n for higher throughput
- 802.3af PoE input
- IP67 enclosure to allow the unit to be mounted on the pole
Solution
Antaira's industrial grade PoE switch with its 4 10/100TX 802.3af PoE ports and one non-PoE port for uplink or configuration was used to power the cameras and access point. The switch and 48VDC power supply were mounted in a NEMA4 enclosure on the same pole as the IP cameras and access point.
Two 802.11n AP/bridge/repeaters that support the IEEE specification of wireless distribution system (WDS) for the wireless transmission were also used by the city. In a typical wireless AP – client network only one IP address can be transmitted from the client radio to the access point. In the proposed network, there would be two cameras, each with their own IP address being transmitted to the access point across the lot to the central server. In order to allow for both streams to be transmitted simultaneously, the 802.11n AP/bridge/repeaters needed to be set up in bridge mode with WDS enabled, a protocol that adds additional address fields in the WLAN frame to allow for multiple IP address to be sent from one “client”.
One 802.11n AP/bridge/repeaters was then mounted on the same pole as the IP cameras and connected to the industrial grade PoE switch and the other unit was mounted on the outside of the building that housed the server. This 802.11n AP/bridge/repeater was then simply plugged into a PoE switch already located within the building.
Product solution highlights
- Wide operating temperature allows the system to be installed anywhere in the city
- PoE input for the APX-3100 allows it to be powered from the same switch as the IP cameras
- 802.11n radio gives the bandwidth needed to support multiple IP cameras
- IP67 enclosure allows the APs to be mounted outside