Another trend in network technology and cabling is the increasing use of Ethernet protocols in new application areas. This includes many automation protocols and increasingly sensor/actuator applications.
Numerous traffic and transport platforms such as rail, tram, bus, ship and aircraft, are fitting their fleets with Ethernet.
Whilst Ethernet has been successfully employed, in particularly for passenger information systems and for WLAN services for many years now in the methods of transport mentioned above, it remained more or less unused in the private car/truck market for a long time. In this article we will discuss single pair Ethernet transmission and its benefits.
The automobile industry has now recognized the advantages of Ethernet and started an initiative to develop Ethernet protocols for short-distance transmission routes in vehicles. The solution is called: single pair Ethernet transmission for distances up to 15 m or 40 m.
This Ethernet technology has since been published in the standards (Gigabit Ethernet over single-pair balanced copper cabling) and 802.3bw 100Base-T1 (100 Mbit over single-pair balanced copper cabling).
To achieve simultaneous transmission of data and energy, PoDL was also defined under IEEE 802.3bu (Power over Data Lines = a principle suitable for single pair transmission for remote powering). On the basis of these standards chipsets, devices, cables and connecting hardware are now being designed, developed and produced for integration in private cars.
Cabling for private cars focuses on a transmission distance of up to 15 m and, in general, needs to be produced in unshielded form due to weight and spatial constraints. Larger vehicles such as trucks and buses require longer single pair Ethernet transmission distances of up to 40 m and due to the associated higher EMC requirements, need to be fully shielded.
In fact, the latter single pair shielded transmission distance also has other “non-automotive” application groups and has piqued the interest of manufacturers. This is because, in general, shielded single-pair Ethernet cabling offers all of the features required to fulfill the mega trend described above.
They are fast, space-saving, cheap and simple to implement. For this reason, industry, whose automation profile is now largely based on 1000 Mbit Ethernet (100BASE-TX), is showing increasing interest in solutions with single-pair Ethernet.
In fact, within building automation developers are actively considering the different possibilities provided by integrating single pair Ethernet within the hierarchy and structure of contemporary building cabling. Then there are also numerous other application areas, which present attractive opportunities for the development of single pair Ethernet.
The interest in single pair Ethernet transmission also reflects a general trend in standardized network cabling – diversification of structured cabling for specific application areas. ISO/IEC JTC1 SC25 WG3 currently includes activities or projects which deal with the realization and implementation of the technical results of IEEE 802.3 within structured building cabling.
