UK What PoDL is
PoDL stands for Power over Data Lines. It is the IEEE 802.3bu amendment, published in 2016, which adds power delivery to single pair Ethernet (SPE) links such as 100BASE-T1 and 1000BASE-T1. A power source puts DC power onto the same twisted pair that carries the data, and the powered device takes it off at the other end.
The idea is the same as Power over Ethernet (PoE): one cable instead of two, fewer connectors and a device that can be installed wherever the network reaches. The method is different. PoE was designed for the four-pair cable of standard Ethernet and sends power on two or four of those pairs. A single pair link has no spare pairs, so PoDL puts the supply on the data pair itself, separated from the signal by coupling and filtering at each end.
PoDL was shaped by the automotive industry, where every metre of copper adds weight, and is now also used for industrial sensors. Its long-reach industrial extension for 10BASE-T1L, added by IEEE 802.3cg, is often called single pair Power over Ethernet, or SPoE.
How PoDL delivers power
A PoDL link goes through a short sequence before full power flows.
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Detection. The power sourcing equipment (PSE) applies a small, current-limited signal and looks for a valid powered device (PD) signature, so it never puts full power onto a cable connected to equipment that cannot take it.
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Classification. The PSE and PD agree a power class. IEEE 802.3bu defines classes for 12 V, 24 V and 48 V systems, and the Serial Communication Classification Protocol (SCCP) lets the two ends exchange class information over the pair.
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Power-up. The PSE switches on the agreed supply. Inductors keep the DC away from the PHYs, and capacitors keep the data signal away from the power circuits.
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Monitoring. The PSE watches the current and removes power if the PD is disconnected or draws more than its class allows.
PoE vs PoDL vs SPoE
| Feature | PoE | PoDL | SPoE |
|---|---|---|---|
| Standard | IEEE 802.3af, 802.3at and 802.3bt | IEEE 802.3bu (2016) | IEEE 802.3cg (2019), classes 10–15 |
| Data links | 10BASE-T to 10GBASE-T | 100BASE-T1, 1000BASE-T1 and other SPE links | 10BASE-T1L long reach |
| Pairs carrying power | Two or four | One, shared with data | One, shared with data |
| Supply | Around 44–57 V | 12 V, 24 V and 48 V classes | Higher-voltage classes, around 30 V and 50 V |
| Power at the device | Up to 71.3 W | Around 0.5–50 W, depending on class | Around 1.2–52 W, depending on class and cable length |
| Typical reach | 100 m | Short, typically tens of metres | Up to 1,000 m |
| Typical use | Cameras, access points, PoE computers | Automotive cameras and sensors | Industrial field devices |
The two families are not interchangeable. A PoE switch cannot power a PoDL device, and joining PoDL equipment to a four-pair port, or the reverse, needs purpose-built conversion.
Sharing one pair works because power and data occupy different parts of the spectrum. The supply is DC, while the data signal is a high-frequency waveform with no DC content, so simple filters can pull them apart again at the far end. The design challenge is keeping noise from the power circuits out of the data path, which is why PoDL specifies the coupling networks closely.
Where PoDL is used
PoDL is young compared with PoE, and most uses fall into three groups.
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Vehicle cameras and sensors. Cameras, radar and other sensors on automotive Ethernet links, where dropping a separate power cable saves weight and connectors.
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Industrial sensors. Single pair sensors on machines and in cabinets, and long-reach field devices using SPoE on 10BASE-T1L.
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Building systems. Small sensors and actuators on long single pair runs, where a local power supply would be awkward to fit.
Choosing between PoDL and PoE
The choice usually follows the network, not the power. If the devices already use standard Ethernet cabling with RJ45 or M12 connectors, PoE is mature, widely supported and delivers more power per port; our white paper on industrial Power over Ethernet covers its standards and power budgeting. If the design calls for single pair Ethernet, because of reach, weight or connector size, PoDL or SPoE is the way to power it, and the power class should be agreed with the device maker early.
Cable matters on both sides. A single pair carrying power has to handle the current without too much voltage drop, so conductor size and run length set the usable class, much as they do for PoE. Our explainer on PoE PD vs PSE covers the source and device roles that PoDL borrows.
Our white paper on single pair Ethernet in industrial and edge AI computing sets PoDL against the SPE data variants and connectors. In our range, single pair Ethernet appears today as data links: several of our in-vehicle computers list 1000BASE-T1 automotive Ethernet ports.
Quick answers on PoDL
PoDL: common questions
Is PoDL the same as PoE?
No. Both send power with data, but PoE uses two or four pairs of standard Ethernet cable and PoDL uses the single pair of SPE. They are not compatible.
What is the difference between PoDL and SPoE?
Reach and use. PoDL in IEEE 802.3bu targets shorter automotive and industrial links. The SPoE classes in IEEE 802.3cg extend it to long-reach 10BASE-T1L cable.
How much power can PoDL deliver?
Up to around 50 W at the device. The exact figure depends on the class, the supply voltage and the cable.
Can PoDL power a camera?
Yes, if the camera uses single pair Ethernet. Automotive cameras were one of the main reasons PoDL was developed.
Does PoDL work on a 10BASE-T1S multidrop bus?
Not under the original standards. PoDL is point to point. Powered multidrop is being developed separately in the IEEE 802.3da project.
When a design calls for single pair Ethernet, we fit the right T1 interface in the edge computer as standard and set up the drivers before the system ships.