The cost of installing new equipment for any new on-board project can be expensive and replacing existing cables is extremely costly. It also may not even be an option, considering how complex a new installation can be. In most cases existing cables can be reused and utilised, especially for data communication.  
 
Traditionally, modern fleets are designed with Ethernet Backbone Networks (EBN) enabling easy and modern communication across trains. However, not all trains are new, with many thousands of fleets existing with years of life left in them. Older fleets that must be retrofitted have options to modernise, commonly using old and existing cabling.  
 
Nevertheless, on-board networks are inherently complex. Trains are required to be coupled, re-coupled and will swap directions many times throughout the day. During the coupling phase, they will connect both non-critical (i.e. Passenger Information Systems) and more importantly critical systems (i.e. Door control) together. 
 
Couplers have a series of pins that are securely fastened for transit. If this connection fails, the train cannot be in service, meaning they are a vital part of the integrity of the overall system. During modernisation phases of fleets and on-board train systems, communication between trains can utilise couplers using a pair of existing cables.  
 
One of the main challenges of couplers is the limited supply of available pairs. Pairs can be used for a variety of features such as power or critical systems. These pairs are likely to be prone to noise and may not be shielded either, making them not suitable to use for data communication.  
 
When it comes to data communication, generally connections are required to be good, preferably with shielding. Poor lines can cause communication loss or sporadic interference. Additionally, if there is voltage on the line, regardless of the quality, data communication is not possible.  
 
To achieve communication between trains via couplers, Westermo’s Viper-002-PL has been designed to handle the harshest of environments. In an IP67 housing and M12 connectors, the Viper-002-PL is perfect for any on-board solution complying to EN 50155.  
 
The device has two ports. One is a 100Mbit/s copper Ethernet port and the other a 2-wire cable port for communication. Since they work in pairs, the 2-wire cable ports will connect between two Viper-002-PL’s via an on-board coupler. Automatically negotiating with each other, the Viper-002-PL is surge resistant and immune to electrical interference.  
 
After negotiating, Ethernet traffic will seamlessly communicate over the coupler, enabling data communication on a train. If the train is required to be uncoupled and connected to another train, they will disconnect and reconnect to the new Viper-002-PL.  
 
There is one extra feature of the Viper-002-PL that should not be ignored. The connection between couplers is often powered, up to 110VDC. This means that conventional Ethernet traffic cannot tolerate electrical interference on the same wires, meaning it would not be possible for communication. The Viper-002-PL complies to a standard that enables Ethernet over Powerlines to ensure communication in the most harsh and complex environments is possible, ensuring trains can operate networks via couplers.  
 
The Viper-002-PL is a perfect product for any retrofitted on-board system to ensure high quality, secure and robust data communication over train couplers.