Gearing Up for Single-Pair Ethernet in the Enterprise

So Why Do We Have It?

Low-speed fieldbus for machine-to-machine (M2M) communications is found over a range of protocols, media, conductor sizes, distances and connector types depending on the application. Terminal block connections are currently the most prevalent for controllers and devices such as sensors that detect heat, moisture, pressure or other environment factors, or actuators that control valves or other switches such as relays.

Due to all these variations, 10BASE-T1S and 10BASE-T1L were developed to bring interoperability to these systems, allowing them to operate over standards-based generic cabling systems and protocols and ultimately eliminating proprietary interfaces and cables. And 10BASE-T1L also paves the way for integrating devices with systems that operate over the traditional LAN.

So why not just use existing 10BASE-T that operates over four-pair cabling? The answer is simple – they don’t need it. Since these low-speed devices only need a single pair, it makes sense to have an application and associated components that minimize cost and keeps the overall size of cables and connectors at a minimum by eliminating unused pairs.

What’s Different?

Unlike traditional 10BASE-T applications, 10BASE-T1L will allow up to 10 in-line connectors. The application will also accommodate cabling configurations referred to as a mixing segment. In contrast to traditional link segments, a mixing segment (sometimes referred to as a multi-drop) can support more than two devices in a channel. While it remains to be seen how this configuration will be utilized, it is anticipated that some building automation systems in the commercial enterprise space may take advantage of this configuration. 

10BASE-T1L will also aim to support remote powering for the low-speed devices it connects, like what we see today with PoE technology but not compatible with two- and four-pair Type 1, Type 2, Type 3 and Type 4 since it’s a single-pair application. The 802.3bu standard, referred to as Power over Data Lines (PoDL), aims to support up to 13.6W of power over a single pair.

What’s the Same?

Like other IEEE enterprise applications, 10BASE-T1L will be supported by commercial TIA and ISO/IEC cabling standards currently in development. For the commercial enterprise environment, ANSI/TIA-568.0-D-2 Single Balanced Twisted-Pair Use Cases and Topology and ANSI/TIA-568.5 Single Balanced Twisted-Pair Cabling and Components standards are already under development, and naturally ISO/IEC is also working on documentation to define performance parameters.

ANSI/TIA-568.5 will specify multiple channel configurations with various distance limitations and bandwidth, including the 1000-meter, 10 connector configuration and a more desirable 100-meter configuration with four connectors (sound familiar?), which is expected to gain momentum as the choice for generic support of single-pair Ethernet in the enterprise. Both TIA and ISO/IEC have also already identified a single-pair connector design from CommScope for commercial enterprise environments.

The 568.5 standard will also include field tester specifications to verify the performance of installed single pair cabling using familiar performance parameters such as return loss, insertion loss, PSANEXT, PSAFEXT, PSAACRF, TCL, ELTCL and propagation delay. So, it’s no surprise that Fluke Networks is already gearing up for these emerging applications by participating in the standards committees and working with manufacturers as they work to develop the components.

As we did with past standards (think Category 8), you can rest assured that we will continue to stay on top of the standards development and strive to support testing of single-pair Ethernet applications in the enterprise when systems start to deploy. However, because we are only dealing with a single pair, there will likely be no need for familiar pair-to-pair parameters such as NEXT and ACRF.

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