The switches will be used to connect terminals in the individual train sections, which will themselves be interconnected via the access points. This facilitates fast data communications over the entire length of the train. At the same time, the solution offers an economical alternative to an entirely cable-based network. There will be no need for broadband connections in the railcar couplings, because they only need to transmit the data needed to verify the access points at rates of just a few Baud. The systems also possess a serial interface and appropriate drivers, which they use to exchange their MAC IDs. In this way, external radio signals will have no effect on communications within the train network.
The WLAN access points of type BAT 300 F, which fulfils the requirements for protection rating IP65/67, also support the IEEE802.11n transmission standard. This makes data rates of up to 300 Mbit/s possible. The integrated MIMO technology (multiple input multiple output) ensures a stable radio connection even in the event of reflections or other forms of interference. Since they also offer the performance range of a layer 3 router, it is possible to set up a subnetwork for each train section and assign these to the access points via the serial interface.
The IP67 switches from the OCTOPUS series, which support fast redundancy protocols and a variety of security mechanisms, have up to 24 Fast Ethernet ports with vibration-proof M12 connections. Eight of these ports provide for Power over Ethernet and can therefore be used to supply the train’s monitoring cameras with up to 13W via the existing data cable, without the need for any additional cabling.
With this onboard WLAN solution, Belden has once again demonstrated its market leadership in data communications for rail vehicles. As Product Manager Olaf Schilperoort says: “WLAN systems with a serial connection for low data rates—a solution we are now patenting—enable trains to be provided with high-speed Ethernet networks without any costly conversion work, just by using the existing connectors contained in the couplings. This makes it possible to implement numerous applications that offer passengers additional safety and convenience.”
Hirschmann, a Belden Brand, manufactures Ethernet switches, wireless access points, firewall/VPN routers and network management software for harsh industrial environments. The Hirschmann brand stands for experience and expertise in the automation, power transmission and distribution, transportation and energy industries, having pioneered the development of Ethernet as a common standard for industrial control systems. Hirschmann products ensure hassle-free and secure data communication under the harshest conditions due to their ruggedized design and construction.