Digital fallback increases availability and cost-efficiency of audio communication systems
“Dear passengers, welcome aboard the intercity train to Ghent and Antwerp Central Station. The next stop is Waregem.” On-board communication means reliable audio broadcasts. In this respect, the architecture of the on-board audio communication system must be carefully considered. To ensure high functional reliability, a fallback method is no luxury. Kristof Boerjan, Product Manager at Televic GSP, discusses the Televic GSP’s Train Audio Communication System (TRACS) and the importance of its innovative digital fallback.
“Our audio platform for railway applications – TRACS – is a complete audio solution consisting of modular and configurable base components or devices”, Kristof says. “The TRACS product line stands for high quality audio and functional reliability. On top of that, its configurability, modularity and security make sure we can provide our customers with a state-of-the-art and flexible future proof platform.”
“The TRACS functionalities enable many different on-board communication expressions. These vary from crew messages to passengers, playback of pre-recorded messages, to warning tones and music broadcast via the Public Address system. The intercom functions ensure crystal-clear communication between crew members and between passengers and the train crew.”
Some of the advantages of TRACS:
- Superior audio quality with state-of-the-art audio algorithms, low latency, high intelligibility even at severe ambient circumstances
- High reliability: functional reliability increase by architecture choice using same base components, both analog and digital fallback support
- Low risk & upgradable: thanks to the modular approach and up-to-date software stack
- Secure maintenance interfaces
- Configurable: customization via parameterization of “proven design” software: zoning, audio settings, priorities, functional behavior of IO, etc.
- Designed to optimize the total cost of ownership (TCO): in order to be efficient during the full product lifecycle, it’s easy to integrate, commission, install and maintain, different architectures for different needs with plug and play operation and long term support.
Analog or digital fallback?
Kristof: “In the past, audio system providers implemented the communication between the different audio devices via analog (UIC568 based) train lines. This communication method is still used today, but mostly as an analog fallback method when the main communication via the Ethernet backbone is failing. Although UIC568 has been used for a long time, it has a number of shortcomings to support up-to-date audio fallback functionalities".
More is possible with digital
“Due to the functional restrictions of analog fallback – the lack of Passenger Emergency Communication for instance – , we have invested in a fallback method with extra possibilities”, Kristof says. The method is based on standard technology already used in railway applications: daisy chained Ethernet in combination with Power over Ethernet (PoE). By using a digital link, we eliminate the restrictions of the analog fallback with support for multiple audio streams and a digital communication channel among others. Another advantage of digital fallback is the identical functional behavior compared to “normal mode” operation. Passenger and crew should not be aware whether the function is executed in normal or fallback mode.”
More reliability and less maintenance
Kristof: “Our digital fallback network works completely independent from the main Ethernet Backbone. Besides of that, diagnostics of this back-up network are never intrusive, which means that they can be performed continuously behind the scenes when the public transport vehicle is in operational service. The digital fallback method with monitoring functionality won’t leave any dormant failures behind.”
“Furthermore, TRACS is designed to optimize TCO by leveraging plug and play operation, a configuration toolset for commissioning, advanced diagnostics and troubleshooting. This implies lower maintenance and a higher cost-efficiency in the long run.”
“This digital fallback mode enables an unprecedented level of availability of audio functionality.”
– Kristof Boerjan, Product Manager at Televic GSP
Leveraging digital fallback to implement cost-efficient audio system topologies
Kristof: “Instead of increasing the functional reliability of the system, we also offer our customers the possibility to leverage the digital fallback network as alternative to locally interconnect the TRACS devices. By largely reducing the number of required (PoE) Ethernet switch ports, the total system installation cost is optimized. Since the same base components or devices are used, our customers are assured of the same level of audio quality and “proven design” as for the standard topology.”