OVERVIEW
This document describes information related to Power over Ethernet (PoE) and ClearOne’s PoE supported CONVERGE Pro 2 (CP2) P-Link Peripheral Pro Audio products.
To power a ClearOne P-Link device, you must use a Mode B PoE injector that supplies power on pins 4, 5, 7 and 8. To daisy-chain multiple P-Link devices, you should use a PoE+ injector that provides 56 volts.
Power over Ethernet (PoE)
PoE refers to passing electric power through a twisted pair Ethernet cable. Basically, this allows a single Ethernet cable to provide both a data connection and electric power to devices.
PoE has been standardized by IEEE 802.3 standards. Accordingly, there are two types available:
- PoE: This is covered by the 802.3af standard and provides up to 15.4 Watts of DC power.
- PoE+ or PoE Plus: This is covered by the 802.at standard and provides up to 25.5 Watts of DC Power (over two pairs).
Note: Since the original article there has been a new PoE standard introduced covered by 802.3bt (4PPoE) which provides up to 71.3 Watts of DC power. However, it is not required for the peripheral devices covered in this article.
TERMINOLOGY
Power Sourcing Equipment (PSE): This is a device that provides DC power on the Ethernet cable. Examples of PSE devices include PoE Ethernet Network Switches, and PoE Power Injectors.
End-Span: When the PSE is an Ethernet Switch, then it is called as End-Span device.
Mid-Span: When the PSE is NOT an Ethernet Switch, then it is called a Mid-Span device. For example, PoE Power Injectors.
Powered Device (PD): This is a device that consumes DC power through PoE. Power comes from PSE through an Ethernet cable to a PD.
Examples of Powered Devices include some IP Phones, IP Cameras, Wireless Access Points, ClearOne Beamforming Mic Array 2, ClearOne USB Expander.
PSE POWERING PD
As per PoE standards, there are two modes available for powering devices. They are referred to as:
Mode A
• Delivers power on the data pairs of 100-BASE-TX or 10-BASE-T cable.
• That is, pins 1 & 2 form one side of the DC supply and pins 3 & 6 form the other side.
• These are the same two pairs used for data transmission. That is, mixed data and power.
• This is similar to the phantom power technique used for powering microphones.
• In summary, mode A uses only 2 pairs for data and power.
Mode B
• Delivers power on the spare pairs of 100-BASE-TX or 10-BASE-T cable.
• That is, pins 4 & 5 form one side of the DC supply and pins 7 & 8 provide the return.
• These are spare pairs and these spare pairs are used for power. That is, no mix of data and power.
• In summary, mode B uses 4 pairs for data and power.
CLEARONE PRO AUDIO PRODUCTS THAT SUPPORT POE (PDs)
• Beamforming Mic Array 1 (White & Black)
• Beamforming Mic Array 2 (White & Black)
• USB Expander
• GPIO Expander
• DIALOG® 20 Wireless Receiver
• Touch Panel Controller
CLEARONE POE POWER INJECTORS (PSEs)
• PoE Power Injector
• PoE+ Power Injector
This below table shows ClearOne products that support PoE (i.e., PDs), PoE modes supported for powering from PSE, PoE Power injectors (i.e., PSEs) that we offer and the number of PD devices that can be supported.
* This has to be the last device in the P-Link chain when daisy-chained with other PDs.
NOTE: Beamforming Mic Array 1 won’t work with CONVERGE Pro 2 and its other peripheral products. It is included in this table just for comparison and reference.
CONVERGE Pro 2 P-Link peripheral devices (Beamforming Mic Array 2, GPIO Expander, USB Expander, DIALOG 20 Receiver) only support Mode B because...
• They send audio, control and power through proprietary P-Link connection.
• They support daisy-chaining multiple peripheral devices in the same P-Link chain that also daisy-chains power.
• It is an economical method for such a solution.
• It reduces the overall system price by reducing the number of PSEs needed to support a larger number of PDs.
3RD PARTY PSEs
ClearOne PDs listed above work with the following 3rd party Mid-Span PSEs, as long as they meet the following requirements:
• PoE powering Mode supported as per the above table
• PoE standard PSEs (48 volt) can be used to power 1 peripheral device
• PoE+ standard PSEs (56 volt/36 Watt) can be used to power up to 3 peripheral devices
ClearOne peripheral devices (except for the Touch Panel Controller) are not regular Ethernet Network protocol supported products. They use our proprietary P-Link protocol. Therefore, they cannot be connected with End-Span PoE Network Switches for power.
BMA CT
The BMA CT also supports PoE in a combination of ways:
• Via the dedicatd PoE In port, which will accept power from either a Mode A or Mode B PoE+ Injector (802.at). This mode is required when using the on-board amplifier outputs. (In this scenario a third party injector such as the TRENDnet TPE115GI (Mode A type) can be used).
NOTE: When the above method is used, a 2nd cable will need to be run to the BMA CT (one from the PoE injector, one from the P-Link out of the CP2 to the P-Link in of the BMA CT).
• Via the P-Link in port on the BMA CT (via the CP2's P-Link PoE port) - this mode will only allow the use of a Mode B (ClearOne Part Number 910-3200-202) PoE Injector, as the CP2 P-link PoE port will only pass power via a Mode B Injector.
The arrays must be powered by an external PoE source that supports Mode B type power delivery. (A PoE Network Switch generally will not work for this.) A PoE injector can either be connected to P-Link PoE port on the rack-mounted CP2 unit, or it can be connected directly to the array’s PoE In port.
When driving 2x10W speakers, each array requires its own PoE injector. When the PoE injector is connected to the CP2 unit’s P-Link PoE port, the CP2 unit’s P-Link Out port will provide both power and data communications to the array. If the PoE injector is connected directly to the array PoE In port, a second cable must be connected from the CP2 unit’s P-Link Out port to the array P-Link In port. (Note that the CP2 unit itself does not provide PoE power without an external PoE injector.)
ClearOne PoE power supply part number 910-3200-202 is recommended, and will power up to three P-Link devices. Some third-party PoE injectors will work, but not all. Mode B PoE injectors that meet the PoE IEEE 802.3at specification should power three devices.