# Ethernet-APL

Protocols · `Ethernet-APL` · verification: source checked

Ethernet-APL is a two-wire Ethernet physical layer for process automation and hazardous locations, based on 10BASE-T1L. It provides 10 Mbit/s full-duplex communication and power over cable runs up to 1000 m using trunk-and-spur topology with point-to-point segments. It is intended to carry higher-level Ethernet protocols such as PROFINET and OPC UA.

## Specification

| Property | Value |
|---|---|
| Transports | ethernet_l2 |
| Architecture | client server |
| Encoding | binary |
| Standard body | IEEE and IEC |
| Standard ref | IEC TS 60079-47; 10BASE-T1L |

## Connected

- Related: [OPC UA](https://machineschema.com/protocol/opc-ua.md), [PROFINET](https://machineschema.com/protocol/profinet.md)

## Safety

- Designed for hazardous locations and supports all explosion protection techniques including intrinsic safety.
- IEC TS 60079-47 (2-WISE) defines intrinsic safety protection for all hazardous Zones and Divisions and provides simple verification steps without complex calculations.
- Ethernet-APL port profiles cover multiple power levels with and without hazardous area protection.
- Spur segments carry lower power and can have optional intrinsic safety for lengths up to 200 m.
- PROFINET over APL devices are certified under the same criteria as other PROFINET devices.

## Study notes

- Based on IEEE and IEC standards; uses 10BASE-T1L single-pair Ethernet.
- Specifies point-to-point connections only, with each connection between communications partners forming a segment.
- Uses a switched architecture and a trunk-and-spur topology.
- Trunk cable lengths can reach 1000 m; spur lengths can reach 200 m with optional intrinsic safety.
- Can power up to 50 field devices with up to 500 mW each.
- Defines two switch types: a power switch that feeds power and communication into trunk ports, and a field switch that provides at least one spur port and can be powered via the trunk or externally.
- Defines port profiles for multiple power levels with and without hazardous area protection.
- Reuses existing fieldbus cable type A and uses FISCO installation practices.
- Requires conformance testing for devices and components.
- The APL Project was established in 2018 and backed by FieldComm Group, ODVA, OPC Foundation, and PROFIBUS & PROFINET International.

## Sources

1. [Ethernet-APL](https://www.ethernet-apl.org/) (accessed 2026-10-25)
2. [Ethernet - APL](https://www.profibus.com/technologies/profinet/connectivity-technologies/profinet-over-apl) (accessed 2026-10-25)

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