Draft:Single Pair Ethernet

Single Pair Ethernet (SPE) is the transmission of Ethernet over a pair of copper wires and allows for both data transmission via Ethernet and simultaneous power supply to devices.

History
SPE, as a two-wire Ethernet interface 100BASE-T1 with 100 Mbit/s, was developed for automotive applications under the name BroadR-Reach. By reducing it to only one twisted pair of wires with a maximum length of 15 m (unshielded) or 40 m (shielded), it achieved a lighter weight and reduced cable space requirement.

Description
Single Pair Ethernet (SPE) is designed as a seamless IP-based communication from the sensor or actuator to the cloud, with a unified protocol standard for the Industrial Internet of Things (IIoT).

In smart devices, there is increasingly less space available for connectors, which need to provide both power and data transmission. SPE reduces system costs for components and installation, as well as the weight and complexity of cabling, compared to traditional multi-pair CAT5 Ethernet wiring. It is used in industrial, automation, and building technology applications. Additionally, it can replace fieldbuses such as CAN bus and Profibus. The major advantage is that it eliminates the need for gateways to convert to other communication protocols, as required in a fieldbus system. Existing two-wire cable infrastructures can still be utilized.

Ethernet with TCP/IP and TSN Time-Sensitive Networking enables real-time data transmission with significantly higher data rates, encryption, and features for systems with functional safety. Ethernet APL Advanced Physical Layer, for applications in factory and process automation, allows for use in explosion/ hazardous areas (Ex-Zone 0, 1, and 2).

OSI-Modell
Single Pair Ethernet is a part of physical layer in OSI model.

Connector for SPE
For the application areas of automotive, aviation, and industry, connectors are used that are specifically tailored to each respective application. In this section, two-wire Ethernet-APL (Advanced Physical Layer) for process automation and industry connectors of the IEC 63171 specification are described.

Ethernet-APL connector
Der Ethernet-APL connector consists of a rectangular screw-spring terminal block housing with three marked connection ports.

Degrees of protection
Depending on their mechanical design, the connectors meet the degrees of protection IP20 to IP67 (or better).

MICE Classifications ISO/IEC 11801 2-3
The MICE classification describes the typical usage location based on the connector's resistance to mechanical stress (M mechanical), ingress of foreign objects (I ingress), resistance to climatic and chemical influences (C chemical), and immunity to electromagnetic interference (E EMI).

In publications, a long notation can also be found, for example M1/I1/C1/E1 for MICE1.
 * MICE1: Office environment EN 50173-1
 * MICE2: Industrial factory halls EN 50173-3
 * MICE3: Industrial production machines EN 50173-3

European standard EN 50173: Information technology — Generic cabling systems. 1995.

IEC 63171 specifications
Three alliances were formed for SPE connector systems, which made proposals for standardization to the International Electrotechnical Commission (IEC): the SPE System Alliance, the SPE Industrial Partner Network, and the TIA Single Pair Ethernet Consortium (SPEC). The general electrical requirements for the interfaces can be found in the basic standard IEC 63171. The design of the mating faces, dimensions, and mechanical properties of the connectors are described in the subordinated standards series -1 to -7.

Since October 2021, the Telecommunications Industry Association (TIA) Single Pair Ethernet Consortium has been collaborating with the SPE System Alliance.

Cable for Industrial-SPE
Cables for Industrial-SPE consist of two conductors for signal transmission with a shared shield. The typical range for conductor cross-sections is from American wire gauge (AWG) 26 (0.13 mm²) to AWG 18 (0.8 mm²). Larger cross-sections are required for power transmission over data lines (PODL power over data line), especially for long cable lengths (10BaseT1L).

Colors of conductor insulation and designation: