Ethernet dominates the control level of the automation pyramid. The lower and field levels, however, are dominated by other standards. Fieldbus systems dominate where actuators and sensors are networked. For Industry 4.0 to be a reality, seamless communication must span all levels, and not only at the field level. The field level needs new infrastructure. This infrastructure must satisfy particular prerequisites such as being compatible with the Ethernet networks above it and simultaneously be cost-effective and space-saving, as space is tight in many machines. The Single Pair Ethernet (SPE) is the new industry standard. Click here to navigate to the”Predictive Maintenance (Smart Maintenance and Repair) whitepaper for IoT enablement and connectivity. Here we will discuss single pair Ethernet, benefits and applications.

Single Pair Ethernet(SPE)

The SPE cables have only one twisted pair. In contrast, Ethernet cables usually have two pairs or even four pairs of wires. Such an arrangement enables SPE to square the circle. The SPE is nearly as powerful as Multi Pair Ethernet, but it is more compact, allows larger distances, and allows easier installation. SPE ensures reliable and consistent, reliable global networking by making the field level Smart.

SPE ecosystem
Figure1: SPE Ecosystem

Single pair Ethernet vs Industrial Ethernet

Industrial Ethernet needs high-speed communications with extremely high reliability. The cables and equipment in use for Industrial Ethernet should be able to operate in acute harsh environments.

The design of Ethernet cables, switches, and other equipment is such that they can operate over disparate environments and broader temperature ranges where IP ratings are needed.

The robust SPE offers lower data rate links to communicate with actuators, sensors and similar equipment where there is a need for low data rate, ease of installation, and low cost with reduced cable weight.

Although both SPE and Industrial Ethernet cater to industrial environments, they are suitable for different applications. No conflict exists between SPE and Industrial Ethernet.

Benefits of single pair Ethernet

Ethernet finds wide use in modern manufacturing and other related organisations. The SPE can effortlessly add actuators and remote sensors whenever there is a need for automation and general control. The following content discusses a few of them::


The switch from 4-pair cabling setups to a single-pair setup makes cabling infrastructure expansions more affordable. The existing facilities can also retrofit the SPE cables into existing facilities. It can substitute existing wired systems and is generally compatible with terminal block-style connections used by various industrial applications.

Easier to Install

Fewer cables translate to streamlined installation jobs and easier adjustments with changes in configurations. In the event of a glitch, tracking issues along the data or power grid are quicker.

Benefit Industrial IoT Setups

The SPE brings benefits to real-time sensor data applications. Unlike antiquated Ethernet approaches, edge devices connect shorter distances, and the SPE simultaneously links to computers that process tasks linked to faster networks. Speed matters in industrial IoT. This is specifically true for the millions of actuators, relays, and sensors in use throughout manufacturing facilities around the globe. While individual IoT sensors use minimal bandwidth, the sheer volume of connected devices dramatically impacts bandwidth. As production needs fluctuate or scale, organisations lacking sufficient Ethernet infrastructure will fall behind.

Benefit Building and Industrial Automation

SPE also benefits from automated building technology such as lighting and access control and critical processes that companies must run smoothly at all times, without the associated expense and time investment associated with human employees. Single-pair cabling improves performance while reducing costs, from calibration systems to robotic devices to audio-visual components.

Cables for SPE & IEEE standards protocol

Cables are now entirely standardised. The IEEE standard 802.3 describes the protocol standards from which the International Electrotechnical Commission (IEC) has described SPE cables' electrical and design properties in its series of IEC 61156 standards. The IEC 61156 standard classifies SPE cables per their installation type, data transmission rate, and maximum link length. The colour of the cores remains constant: blue for BI_DA+, IEC 61156-12 (flexible application), and white for BI_DA-. IEC 61156-11 (fixed installation) describes the properties of a 1 Gbit/s transmission rate over a 40 m transmission distance. The standard sets high electrical properties requirements to accomplish the high transmission rate via just one core pair. Such a high transmission rate needs a significantly higher bandwidth than conventional Industrial Ethernet Cat.5e data cables. The bandwidth specification is thus for a maximum frequency of 600 MHz. The IEC 61156-13 (fixed installation) and IEC 61156-14 (flexible application) are presently under development for greater distances extending to 1,000 m; the data rate here is 10 Mbit/s. The standards also describe the conductors' cross-sections. They range from a minimum of 16 AWG and 18 AWG (approx. 2 mm core diameter) to a maximum of 22 AWG (approx. 1.6 mm diameter) to 26 AWG (approx. 1 mm diameter). The little thicker 22 AWG, which also have specifically low attenuation, are suitable for PoDL. 26 AWG is suitable for specifically thin cables. The diameter reduces by a quarter of a four-pair cable, and the weight reduces by half – ideal for constricted construction spaces, such as in a control cabinet.

Cross sectionData rateApplicationsIEC standard
26 AWG1Gbit/s 1000BASE-T1 up to 40mFixed installationIEC 61156-11
Flexible installationIEC 61156-11
Continuous flexing installation (e.g. cable chainIEC 61156-12
22 AWG1Gbit/s 1000BASE-T1 up to 40m(optimized for PoDL)Fixed installationIEC61156-11
Flexible installationIEC61156-11
Continuous flexing installation (e.g. cable chainIEC61156-12
18 AWG10 Mbit/s 10BASE-T1 up to 1,000mFixed installationIEC 61156-13
Flexible installationIEC 61156-14
Table1: Cables for SPE & IEEE standards protocol

Applications of SPE

SPE has created a new world of possibilities in Industry 4.0 (Figure 6). Some popular application areas of Single Pair Ethernet are as follows:


In battery-electric vehicles, weight directly translates into better battery efficiency and range. SPE offers a weight reduction of up to 55% and a reduction of the outer diameter. It can also reduce the bending radius by up to 30%.

Public Transports:

SPE is applicable in the following areas in public transport (Table 2)

  • Visual and acoustical Passenger Information Systems (PIS)

SPE is suitable for power and connectivity in public transport. For example, it displays the stops for internal and external speakers and audio systems.

  • CCTV

SPE is present in security measures, including cameras, recorders, and CCTV Monitors.

  • Infotainment

SPE can deliver onboard Wi-Fi as well as in In-Seat Audio/Video.

  • Seat Reservation

SPE can provide seat reservation systems for longer trips. The seat displays or over luggage storage areas are easily connected and monitored.

  • Passenger Counting visual (APC)

Modern transport includes capacity monitoring and route optimization systems. Smart sensors combined with SPE can deliver excellent live monitoring and evaluation data.

ApplicationCable TypeData rateProtocol
Passenger CounterSPE10 Mbit/s10BASE-T1S(MD) OR 100BASE-T1
Door Monitoring and ControlSPE10 Mbit/s10BASE-T1S(MD)
IP SpeakerSPE10 Mbit/s10BASE-T1S(MD)
SOS TerminalSPE10 Mbit/s10BASE-T1S(MD)
DisplaySPE10 Mbit/s100BASE-T1
Driver assistance terminalSPE1 Gbit/s1000BASE-T1
IP-Cameras (indoor/outdoor)SPE100 Mbit/s100BASE-T1
GSM-/WiFi Router and access4-pair1 Gbit/s100BASE-T1
Door openerSPE10 Mbit/s10BASE-T1S(MD)
Ticket vending machineSPE10 Mbit/s10BASE-T1S(MD)
Table2: Application of different SPE protocols in transportation

Practical guidelines for effectively deploying SPE

Users should bear the following in mind when they want to deploy SPE:

  1. Users should assess the new technology, identify application areas and discuss these requirements with manufacturers. Users make important decisions at this stage, and manufacturers must know the customers' system design preferences.
  2. Taking advantage of all opportunities to develop technical knowledge is crucial. The SPE Industrial Partner Network and manufacturers provide exhaustive information material such as webinars or e-learning. There is a rapid development of SPE technology – and it is essential to stay ahead of the industry trend.
  3. "Think outside the box" – SPE technology offers incredible opportunities. Things that previously seemed unthinkable are now possible. It is not just about reducing it to two conductors but also about potential new network structures: trunk capability, power over data line or longer cable lengths are just a few examples. Anyone who keeps themselves abreast of these new possibilities and deploys them in their application can benefit from them to the max.
  4. There's no need to implement every installation in a single pair just because this is possible. This is why we must keep the entire Ethernet network in mind during production. While there are considerable cost savings involved with SPE, in many cases, it is still beneficial to rely on 4 pair Ethernet cables for installation to avoid any potential system operational issues. Users should remember that standard Ethernet devices must be able to connect in the event of future plant expansion.

element14 provides a one-stop platform for the key components for different types of Ethernet and single-pair Ethernet cables and solutions. Some of the product categories are Cat5e,Cat6 and Cat6a and more.


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