Single Pair Ethernet
Single Pair Ethernet (SPE) extends standard Ethernet communication to field-level devices over a single twisted pair, enabling data and power to reach sensors and actuators through simpler cabling, longer reach, and direct IP-based connectivity across industrial systems.
From Legacy Protocols to End-to-End Ethernet
Traditional industrial networks often keep field devices hidden behind gateways and a mix of disparate legacy protocols. SPE extends Ethernet directly to the field layer, creating a unified path from sensors and actuators to supervisory systems and cloud applications—bringing field devices into the security posture of the industrial control system and supporting alignment with IEC 62443 requirements.
How 10BASE-T1L works
10BASE-T1L uses PAM-3 encoding over a single balanced twisted pair to transmit Ethernet frames at 10 Mb/s. The standard defines two signalling levels: 2.4 Vpp for general-purpose long reach and 1.0 Vpp for intrinsically safe applications in hazardous areas (APL). Both operate over the same physical layer, and devices can negotiate the appropriate level at link establishment.
Power over Data Line (PoDL)
PoDL delivers DC power on the same pair of wires used for data, eliminating separate power cabling. IEEE 802.3cg defines power classes from Class 10 through Class 15, supporting up to 52 W at the powered device. The Serial Communication Classification Protocol (SCCP) handles negotiation between power sourcing equipment and powered devices before voltage is applied.
Key Topologies
Point-to-Point SPE Connectivity
For direct field-device connectivity, Zemfyre supports a point-to-point SPE topology in which a secure SPE switch and PoDL/SPoE controller connect over long-distance SPE links to sensors, SPE cameras, media converters, and PoE end devices. This architecture supports up to 1 km links while carrying both power and data, making it ideal for remote IIoT endpoints and distributed sensing applications.
ZEM406LP Daisy-Chain Architecture
For larger distributed systems, Zemfyre's ZEM406LP enables daisy-chain SPE deployments with both data and power forwarding between nodes. Working with the ZEM601L, the ZEM406LP allows multiple devices to be connected in sequence across extended distances, reducing homerun cabling and simplifying installation in building automation and industrial environments. The platform supports off-the-shelf 18–58 VDC or 24 VAC power sources, can power up to 40 devices in the chain without local power injection, and includes a bypass relay to maintain chain continuity during local power loss.
Secure commissioning in the field
ZemLock™ is an iOS and Android app for secure installation, commissioning, and firmware updates of industrial Ethernet field-level devices. Built for OT environments and aligned with IEC 62443 principles, it enables authenticated local access, protected configuration, device locking, diagnostics, and secure updates through simple NFC-based workflows.
Patents
Zemfyre’s patent portfolio covers two core innovations in industrial Single Pair Ethernet: a media converter architecture bridging SPE and legacy Ethernet with integrated PoDL-to-PoE power conversion, and a Secure Unmanaged Switch architecture for the ZEM6xx family with NFC-authenticated field provisioning.
US 12,524,056 B2 · Granted Jan 13, 2026
Ethernet media converter apparatuses and systems
Media converter that interfaces between Single Pair Ethernet (SPE) devices and conventional 2-pair or 4-pair Ethernet devices, including the PoDL-to-PoE conversion architecture used in the ZEM111LP.
Inventors: Alexandre Gourari, Yuri Luskind
GrantedDE 11 2023 000 147 T5 · Filed Jan 10, 2023
Secure Unmanaged Network Switch and Methods
Unmanaged Ethernet switch with locked unused ports and per-port MAC address blocking. A field technician establishes an NFC-authenticated mobile session to change port status or authorize firmware updates over USB or NFC; outside an active session, configuration cannot be modified. Covers the ZEM600L and ZEM601L architectures.
Inventors: Yuri Luskind, Alexandre Gourari, Vassili Nesterov
Patent pending