Single Pair Ethernet


Ethernet is the leading network protocol in LAN applications and is increasingly gaining ground in new areas. At the start of the Ethernet “era” in the early 1980s, coaxial cabling dominated (thick Ethernet – yellow cable, thin or cheap Ethernet), from the 1990s the focus shifted to cabling solutions based on symmetric cabling (twisted pair) and fiber optics.

Single pair Ethernet changes the dynamics.

Initially, twisted pair cabling relied on two-pair cables. This utilized a wire pair as a transmission and reception line (100Base-TX). This principle, limited to a transfer rate of 100Mbit/s, still represents the main transfer principle in industry and automation systems technology today and is often achieved using star-quad cable designs.

In order to achieve higher transfer rates of 1 Gbit/s and 10 Gbit/s, a transfer technique was selected, which requires four symmetric pairs in connection with 8-pole plug connectors.

Now, let’s discuss the transfer of Ethernet with a single strand pair, in other words, a solution that quite obviously runs contrary to the technical development of Ethernet and its associated cabling. This article deals with the background of these developments, with the technical details and the normative activities as well as the applications for single pair Ethernet.

We consider the performance of new chipsets and discuss the classification of single-pair cabling with respect to existing two and four-pair versions as well as future n-pair cabling.

Mega trends in information and communications technology (ICT) and their effects

The development of new communication technologies and their associated cabling philosophies, are influenced and driven in no small way by the current ICT mega trends, such as IoT, Industry 4.0 (I4.0), cloud computing and smart technologies.

This leads to new demand profiles regarding communications technology and the network infrastructure behind it, based on cables and connectors. Demands on this technology include: high availability, short access times incl. to distributed data and fast transport of this data from A to B.

Secure transfer of large datasets in different application areas up to determinism (real-time transfer, i.e. guarantied data transfer within a defined time-frame).

At the same time, data transfer should remain cost-efficient. For devices, cables and connecting hardware this means: they must achieve higher performance, be smaller and stronger as well as possess a high degree of modularity and compatibility (exchangeability and plug-compatibility).

These demands can only be fulfilled through innovation, i.e. new development of products with consistent international standardization.