Single Pair Ethernet (SPE) is a new physical layer of Ethernet based on the IEEE 802.3cg (10BASE-T1L) standard. Unlike traditional Ethernet, it uses a single twisted pair of wires instead of four, which reduces cable volume by half and allows for more compact and cheaper connectors. The technology supports Power over Data Line (PoDL) according to the IEEE 802.3bu standard, enabling power and data transmission over the same line.
In industrial networks, SPE provides a speed of 10 Mbps, with future versions increasing to 100 Mbps, and a transmission distance of up to 1,000 meters without repeaters. It supports standard industrial protocols such as PROFINET, EtherNet/IP, Modbus TCP, HART-IP, and OPC UA. To resolve connector incompatibility, the PROFIBUS & PROFINET International organization adopted a unified M12-based connector standard (IEC 63171-7) in 2026, with official approval expected in 2027.
Ethernet-APL (Advanced Physical Layer) builds upon SPE (10BASE-T1L) and adds intrinsic safety for use in hazardous areas, including Zone 0/1 where explosive gas mixtures are present. It utilizes the 2-WISE (Two-Wire Intrinsically Safe Ethernet) concept, which simplifies the safety certification process by using predefined electrical parameters for marked devices, eliminating the need for complex circuit calculations.
Ethernet-APL supports two power classes for field devices in hazardous areas: Class A (0.54 W) and Class C (1.17 W). The technology allows for the direct access to diagnostic information and configuration parameters from controllers, SCADA systems, or the cloud. It is particularly applicable to the chemical, oil and gas, and pharmaceutical industries. Moxa's TWS-3010 series switches are an example of hardware that allows monitoring signal quality and remote rebooting of devices.
For existing 'brownfield' installations, Ethernet-APL can use existing Type A two-wire cables, though testing is required. The transition is further facilitated by HART-IP for millions of existing HART devices. Development is ongoing for 100BASE-T1L to increase speeds to 100 Mbps, and the semantic communication (SemCom) concept is being developed to move beyond raw data streams to meaningful information.