Single-Pair Ethernet for IoT

When most of us picture an Ethernet cable, images of a 4-pair CAT5e or CAT6 twisted pair with an RJ45 connector immediately comes to mind. After all, this is the dominant cable type that connects our PC's, servers, and other devices to a LAN using copper. Yet for some IoT projects, 4-pair cabling using traditional IEEE 802.3 Ethernet standards isn't ideal for a variety of reasons. That's why there’s growing interest in single-pair Ethernet (SPE) and the relatively new IEEE 802.3cg Ethernet standard that operates over SPE. Combined, they offer the optimal balance of speed, distance, and power delivery for many IoT projects -- all while using the same Ethernet and TCP/IP protocols we know and love.

The IEEE 802.3cg standard that leverages SPE is also referred to as 10BASE-T1L. It currently offers 10 Mbps full-duplex speeds at distances up to 1KM. Thus, 10BASE-T1L provides plenty of throughput for many IoT purposes at distances that far exceed the 100-meter maximum inherent in 10/100/1000BASE-T Ethernet standards. SPE also supports power over data line (PoDL) that provides enough wattage output for most IoT components and sensors.

For Industrial IoT (IIoT) or smart building projects, controllers and sensors for power and network connectivity purposes. This will require brand new cable runs to be deployed inside buildings, manufacturing plants, and other industrial/commercial facilities. But in many cases, the existing Ethernet cabling supporting the corporate LAN or manufacturing plant is cumbersome enough. The thought of installing hundreds -- or even thousands -- more CAT6 or better cabling would only exacerbate this issue due to the added size and weight. One immediate advantage of SPE over 4-pair cabling is that it shrinks the cabling size and weight to 1/4 of a typical CAT6 cable. It will also be cheaper to purchase and install. Additionally, IoT projects can repurpose existing 4-pair copper cabling for SPE uses. Thus, in some situations, new cabling won’t need to be run.

Another benefit with single-pair Ethernet is standardization to one network protocol. Legacy plant and facility automation systems typically operated using one of several serial bus technologies as opposed to Ethernet. This created fully isolated networks. One for the manufacturing or facility network – and another for the corporate data network. 802.3cg will allow these networks to be combined natively. This is especially important as Industrial IoT and building automation systems begin to be managed from the public cloud.

The use cases for SPE and 10BASE-T1L are plentiful. In manufacturing plants, SPE can be used to network automation and process control systems. In many situations, this would be a major upgrade on the plant floor away from serial bus technologies that have been in use for decades. In business and commercial settings, SPE can be deployed for physical security door controllers, surveillance cameras, motion detectors, smart lighting, building- or city-wide automation and elevator control systems.

As of right now, the options to deploy SPE and 10BASE-T1L in your facilities are limited. Most Ethernet-based IoT devices still use standard 4-pair Ethernet for connectivity. That said, look for SPE-capable devices to begin rolling out to the manufacturing and enterprise markets soon. Also, expect SPE to improve over time from a performance standpoint while maintaining the 1KM maximum distance numbers. While speeds are capable of up to 10 Mpbs today, you can expect 1 Gbps speeds in the future. Thus, you can be confident that your SPE cabling deployment will be future-proofed for years to come.