Page 35 - 2019 How-to-Specify E-Book
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Step 4: Consider Cabling Options
The two main cabling standards in use today include twisted pair copper cable and fiber optic cable. Twisted pair copper cabling, used in many Ethernet networks, utilizes a pair of wires to form a circuit that can transmit data. Fiber optic cable is a more advanced option that transmits data as pulses of light through thin, flexible tubes of glass. It’s faster and more secure, but also less versatile and much more expensive. Copper is more physically robust and cost-effective, but it provides slower speeds and is at risk of interference when unshielded.
Step 5: Establish Connector Requirements
Finally, one of the most critical considerations is the interconnection of jumper cables between vehicles. The ideal solution is one that works in harsh railway environments and fulfills all requirements for both standard TCN and high-speed Ethernet communication, as this helps to ensure that the transition to full-Ethernet trains is smooth and cost-effective. Selecting a connector with ruggedized RoHS-compliant plating can help ensure durability and performance. There are also connector solutions available with pretested cable assemblies.
Putting it Into Practice
A major high-speed Italian rail network operator implemented this approach when designing their Ethernet network. Borrowing directly from state-of-the-art data center design, they created a sophisticated network architecture that was able to overcome the challenges of train topology and achieve a high level of fault tolerance.
Italy has an extensive network of high-speed trains.
After defining network performance requirements, they used a highly specialized cabling scheme with fully shielded twisted pair cables and connectors to achieve performance well above Ethernet requirements. Then, when they realized they needed contacts with a higher network threshold than the 4-pole M12 contacts that have been adopted by a few leading European train manufacturers, they contracted with ITT to develop a custom solution.
ITT Veam has a rich history in rail connectors, and its CIR M12 Connectors deliver industry-leading Gigabit per second Ethernet (GbE) transmission, optimal sealing, and extreme shock and vibration resistance ideal for today’s harsh-environment rail communication applications. CIR M12 Connectors are bayonet-coupling circular connectors that combine reliable and robust FRCIR connectors with M12 and coax contacts within a single shell to support up to 10GbE (i.e., up to Class FA ISO/IEC 11801 channel performance), MVB, WTB, and video lines. Available as 1-, 4-, and 7-way variants with 2-, 4- and 8-pole contact options, the series has a minimized circular footprint and is fully compliant with the latest state-of-the-art rail standards for fire and smoke.

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