IEEE 802.3bt™ “Standard for Ethernet Amendment: Physical Layer and Management Parameters for DTE Power via MDI over 4-Pair” is currently under development by the IEEE P802.3bt DTE Power via MDI over 4-Pair Task Force and is anticipated to publish in February, 2018. Available Type 1 and Type 2 Power over Ethernet (PoE) technologies employ two balanced twisted-pairs to deliver remote power. Employing four balanced twisted-pairs to deliver remote power offers many benefits, including improved efficiency and increased power. This project will augment the capabilities of existing Power Sourcing Equipment (PSE) and Powered Device (PD) specifications with Type 3 (≥ 60W at the PSE output) and Type 4 (≥ 90W at the PSE output) requirements and associated power management information. Compatibility with existing PoE equipment will be maintained.
Physical Layer Power Classifications supported by Type 1, Type 2, Type 3, and Type 4 PoE:
The ability for power sourcing equipment (PSE) to query a powered device (PD) in order to determine the power requirements of that PD is called classification. The power classification function is intended to establish mutual identification and may also be utilized for advanced features such as power management. Classification negotiation occurs at safe and low voltage (between 15 V and 20 V) and current (between 50mA and 100mA) levels. Voltages and currents associated with PoE are not applied until the PSE-PD classification negotiation process is complete. Type 1, 2, 3, and 4 powered devices draw a maximum dc input voltage of 57 V.
The current focus of the IEEE P802.3bt DTE Power via MDI over 4-Pair Task Force is circulation of their draft document for Working Group review and comment resolution.
The DTE Power via MDI over 4-Pair Call-For-Interest Consensus Presentation can be found here: http://www.ieee802.org/3/4PPOE/public/mar13/CFI_02_0313.pdf
The Project Authorization Request (PAR), approved on December 11, 2013, with changes from March 18, 2016, can be found here: http://www.ieee802.org/3/bt/P802d3bt_PAR.pdf
The project objectives, adopted on May 15, 2013, with changes from July 17, 2013, (refer to: http://www.ieee802.org/3/4PPOE/objectives_0713.pdf) are as follows:
- The project will amend IEEE Std 802.3-2012 by amending Clause 33
- IEEE Std 802.3 will comply to the limited power source and SELV requirements as defined in ISO/IEC 60950
- Specify Mutual Identification to address four pair operation
- The standard shall not preclude the ability to meet FCC/CISPR/EN Class A, Class B, Performance Criteria A and Performance Criteria B with data for all supported PHYs
- Support for operation over the following channels that have DC loop resistance of no greater than 25 ohms:
- Class D or better 4-pair copper medium from ISO / IEC 11801:2002, including Amendments 1 & 2 ;
- Class D or better media from ISO / IEC 11801:1995;
- Category 5e or better cable and components as specified in ANSI/TIA-568-C.2;
- Category 5 cable and components as specified in ANSI/TIA/EIA-568-A
- Support operation with 10GBASE-T
- The project shall support a minimum of 49 Watts at the PD PI
- Define parameters to limit maximum pair-to-pair current imbalance
- 4PPoE PDs, which operate at power levels consistent with IEEE 802.3-2012 PDs, will interoperate with IEEE 802.3-2012 PSEs
- 4PPoE PSEs will be backwards compatible with IEEE 802.3-2012 PDs
- Update management parameters