10BASE-T1L Ethernet chips enable up to 1.7 kilometer long Ethernet cables

The maximum length of Ethernet cables used to be 100 meters. While that may be more than enough for most applications, it does not cut it for industrial communication applications.  So the 10BASE-T1L Ethernet physical layer standard (IEEE 802.3cg-2019) was approved by the IEEE on November 7, 2019 to allow for cables over one kilometer using a single twisted-pair cable.

Analog Devices has launched two 10BASE-T1L Ethernet chips with ADIN1100 Ethernet PHY and ADIN1110 Ethernet MAC-PHY that allow for up to 1.7 kilometer long Ethernet cables.

10BASE-T1L device

Let’s check out ADIN1100 specifications for reference:

  • 10BASE-T1L IEEE Std 802.3cg-2019 compliant
  • Cable Reach
    • 1700 meters+ with 1.0 V pk-pk
    • 1700 meters+ with 2.4 V pk-pk
  • Auto-Negotiation capability
  • Supports intrinsic safety applications
  • MII, RMII & RGMII MAC interfaces
  • MDIO Management Interface
  • Unmanaged configuration using pin strapping including:
    • Master/Slave selection
    • Transmit amplitude
    • PHY address
  • 25 MHz crystal oscillator/25 MHz external clock input (50 MHz external clock for RMII)
  • Single supply – 1.8 V/3.3 V operation (mode dependent)
  • Power consumption
    • Single supply 1 V pk-pk – 45 mW typ
    • Dual supply 1 V pk-pk – 39 mW typ
    • Single supply 2.4 V pk-pk – 109 mW typ
    • Dual supply 2.4 V pk-pk – 81 mW typ
    • Triple supply 2.4 V pk-pk – 75 mW typ
  • EMC test standards
    • IEC 61000-4-4 electrical fast transient (EFT) (±4 kV)
    • IEC 61000-4-2 ESD (±8 kV contact discharge)
    • IEC 61000-4-2 ESD (±15 kV air discharge)
    • IEC 61000-4-6 conducted immunity (10 V)
    • EN55032 radiated emissions (Class A)
  • 3.3 V/2.5 V/1.8 V MAC interface VDDIO supply
  • Integrated power supply monitoring and POR
  • Start of packet detection for IEEE 1588 timestamp support
  • Diagnostics
    • Frame Generator and Checker
    • Multiple Loopback Modes
    • IEEE Test Mode Support
    • Cable Diagnostics
  • Link/Activity LED
  • Small package 40-lead (6 mm x 6 mm) LFCSP
  • Industrial temperature range – -40°C to 105°C
ADIN1100 block diagram
ADIN1100 block diagram

It’s not mentioned in the specifications above, but 10BASE-T1L’s transmission speed is limited to 10 Mbps which is still much faster than the HART and Field Bus protocols typically used for industrial networking.

HART vs Field Bus vs 10BASE-T1L comparison

Another benefit listed in a white paper is that new graduates may never have heard about HART or Field Bus, but all are familiar with Ethernet, and apart from a passive media converter, or a switch with 10BASE-T1L ports is required, nothing needs to be changed. No additional software, no customized TCP/IP
stack, and no special drivers are required for 10BASE-T1L. Some cables used for HART communication can even be reused, and PROFINET, EtherNet/IP, HART/IP, OPC UA, or MODBUS/TCP and IoT protocols such as MQTT can also be used with the new Ethernet standard.

10BASE-T1L network topology
Typical industrial network topology from office to end node using 10BASE-T1L.

You’ll find more details about the chips on ADIN1100 and ADIN1110 product pages on Analog Devices’ website.

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Via ElecronicsWeekly


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5 Replies to “10BASE-T1L Ethernet chips enable up to 1.7 kilometer long Ethernet cables”

  1. The bit “since 10BASE-T1L relies on a single pair, the transmission speed is limited to 10 Mbps” is inaccurate. There is a series of new single-pair Ethernet standards, 1000Base-T1 is limited to one gig per sec, 100Base-T1 is limited to 100 meg per sec, and 10Base-T1S/10Base-T1L are limited to 10 megs per sec. T1S uses shorter cables (25m) and is multi-drop, i.e. it behaves like a bus as in the good old times of 10Base2, but with much simpler constraints.

  2. Is there some level of compatibility between 10BASE-T1L and 10BASE-T1S? For example, can T1L and T1S PHYs talk together using short cables?

  3. It’s great to see Ethernet evolve a bit more towards single-pair. Long ago I was saying that I’d like to get 250Mbps over a single pair or even 625Mbps nowadays on the same, rather than 4 times this over 4 pairs. But while the physical layer improves, these remain limited to industrial environments. What is currently killing Ethernet is its old and thick connector, that takes too much place on laptops and gets progressively removed. Thinking again about a durable two-wire connector for the next 20 years is really needed, and I imagine that if this happens we’ll find plenty of adapters using only the middle pair of regular RJ45 connectors to connect to it, and that switches will become able to split their pairs to one or multiple T1 connections. Let’s hope it doesn’t die before such a thing becomes a reality though :-/

    1. Single pair with power injected in the pair would be awesome especially if you can do long runs. You could put sensors all over the place without having to resort to wifi, batteries and working out how to charge them.

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