Key Features of POE Injectors

  • All of the above POE adapters/injectors are so inexpensive that you can keep spares at little cost.

Power Over Ethernet was first launched by Cisco in 2000. The standards are IEEE 802.3af and IEEE 802.3at. "Midspan" means the same as POE injector: The term "midspan" refers to the concept of putting a POE injector as close as possible to the device being powered, since some voltage is lost in the ethernet cable.

 

What is a Power over Ethernet Injector?

 

Power over Ethernet (PoE) injectors are electronic devices that are capable of transferring direct current power onto Ethernet cable wires for transmission to a wide range of powered devices via an RJ45 port. They are also known as Power over Ethernet adapters as they are used to convert non-PoE networking to having PoE functionality, by providing an appropriate power supply.

 

Power over Ethernet adapters can be connected via RJ45 ports and plugs to standard network switches to provide an inline PoE power supply. They carry a port for AC input power which is used to supply the injector with its source of power. In this arrangement, PoE injectors function as a midspan device. Midspan PoE devices introduce power onto an existing Ethernet connection using an external power source.

 

How do Power over Ethernet Injectors work?

 

A PoE midspan or injector has a power input, data input, and an out that merges the power and data inputs. The two inputs are converted into a powered output of appropriate voltage and current for the client device. An alternating current (AC) input is also converted to DC, suitable for Powered Devices.

 

About Power over Ethernet

 

Power over Ethernet is a technology that is able to deliver DC power to devices over Ethernet networking cable. This is achieved by using two or four of the twisted pairs that make up Ethernet cable to drive power. The power transfer can take place alongside standard Ethernet data transmission at up to Gigabit speeds with loss of power or performance.

 

Power over Ethernet networking has been standardized by the Institute of Electrical and Electronics Engineers as part of its 802.3 series of standards. Standards were first introduced in 2003 to address the ad-hoc and variable performance of power injector technologies. Currently, there are three key PoE standards released by the IEEE and in widespread use. Recent releases have increased the power available to devices through this technology to over 100 watts. Our selection of Power over Ethernet adapters and injector kits conform to one or more of these key networking protocols:

 

[A] IEEE 802.3af

 

This is the original standard for Power over Ethernet and defines all the basic principles of endspan and midspan powering of devices. This version of PoE, released in 2003, specifies power delivery at a level of 15.4 watts of DC power (44 volts, 350 milliamps per powered twisted pair) that is transferred over 2 of the four twisted pairs within an Ethernet cable. Due to heat dissipation, the minimum power delivered to devices is 12.95 watts. This IEEE standard sets out key strategies that are used by this technology to ensure that power transfer is safe. Power Supply Equipment (PSE) and Powered Devices perform a handshake before the power transfer commences and strict connect/disconnect protocols are initiated. Within this form of PoE, there are sub-levels of power, with PSEs able to negotiate the level of power supply across 3 power class levels (1-3). Devices powered by this form of PoE are known as Type 1 devices and include devices like VoIP phones. It can be run on Category 3 and category 5 cables.

 

[B] IEEE 802.3at

 

This is the second release Power over Ethernet standard known as PoE+. It specifies power delivery over two of the four twisted pairs. PoE+ delivers power at a higher wattage than standard PoE with a maximum power of 30 watts (voltage of up to 57 volts and current of 600 milliamps per twisted pair). Devices that are powered by PoE+ are known as Type 2 devices and include access points and IP cameras. PoE+ is delivered over Category 5 Ethernet cables. PoE+ can be delivered at one of four 0.1 watts stepped power class levels (1-4) negotiated between the PSE and PD.

 

[C] IEEE 802.3bt

 

This is the most recent Power over Ethernet standard, released in 2018. 802.3bt also known as PoE++ delivers a much higher level of power to devices, up to a maximum of 100 watts. PoE++ is distinct from previous versions of PoE as power is delivered over each of the 8 wires within an Ethernet cable. For this reason, it is also described as 4 pair Power over Ethernet (4PPoE).

 

PoE++ is delivered at two rated power levels according to the powered devices served.

 

  • Type 3 devices: deliver maximum power of 60 watts, (usually 51 watts received at the device) with a voltage range of 50 to 57 volts and current of 600 milliamps per twisted pair. Type 3 PoE can be run on Category 5 Ethernet cable. This form of PoE++ can be delivered by signature at one of 6 power class levels (1-6).

  • Type 4 devices: delivers a maximum wattage of 100 watts (71 watts received at the powered device), the highest level of power currently available. The voltage range is 41 to 57 volts and the maximum current on each twisted pair is 960 milliamps. Type 4 PoE has 8 power class levels (1-8).

 

In addition to these standards, PoE injectors deliver power according to a specific mode. The mode refers to the pin assignment mode of the Power over Ethernet mechanism used.

 

  1. Mode A has power delivery over the data pairs of the 4 pairs of Ethernet cable. This corresponds to pins 1 and 2, and 3 and 6 in a 48VDC free polarity arrangement. This mode is used in 10 and 100BASE-TX Ethernet networking with power and data being transferred over two pairs.

  2. Mode B delivers power on the spare twisted pairs in a cable leaving the data pairs free. Pins 4 and 5 (+) and pins 7 and 8 (-). This mode can also be used with 10 BASE-T of 100 BASE-TX

  3. 4 pair transmission mode use all 8 pins for power delivery. The phantom technique is used to delivered power and data simultaneously on all four pairs by exploiting the difference in characteristic frequency of the data and DC power, so they can be separated by the receiving device. This form of transmission is used with Gigabit Ethernet networking 1000 BASE-T.

 

Other features of PoE adapters

 

  • Active vs. Passive PoE Injector

 

PoE is still a very mixed market and not all PoE injectors conform to standards or use certified ports.

 

Active PoE injectors are those that comply with any of the IEEE standards 802.3af, 802.3at, and 802.3bt. The critical feature with these PoE protocols is that a handshake must take place between power sending and receiving devices. Power will not be delivered if the injector is not acknowledged by the receiving device. This makes PoE safer for equipment.

 

Passive PoE injectors do not conform to any of the recognized standards meaning that certain aspects of their safety and performance are not assured. In particular, power may be driven to devices without confirming that it is required or suitable. The power supply cannot be marched or negotiated. Devices can also be over or underpowered causing equipment malfunction or damage.

 

Our range of active Power over Ethernet injectors comply fully with the IEEE standards and provide additional safety and performance benefits for powering devices.

 

  • 12V versus 24V versus 48V PoE Injector

 

PoE injectors are usually one of these voltages, and the injector should be matched to the voltage of the device it will be powering. If there is a significant discrepancy in voltage, a step-down adapter can be used to correct the output voltage.

 

  • Number of output ports

 

Depending on the input power and dimensions of the injector, it may carry more than one PoE output port (e.g 4-port or 8-port PoE injectors). If multiple ports are needed a PoE switch may be a more convenient solution.

 

Ubiquiti PoE injectors and adapters for Power over Ethernet

 

Ubiquiti® PoE injectors are high-specification PoE adapters that can power a range of Ubiquiti devices as well as non-Ubiquiti equipment in accordance with IEEE standards. The range of PoE adapters is broad and spans all power levels.

 

These injectors carry input/output RJ45 ports as well as a socket for 100/240-volt mains power to supply the injector. The input comes from the non-PoE networking equipment and the output drives power to a downstream PD.

 

The Ubiquiti range of PoE injectors delivers DC power at 15 to 54 volts. Current is supplied up to a maximum of 1.5 amps depending on the specific injectors’ specifications. Adapters will either use mode A or B with two pair powering, or power delivery across all four cables.

 

The adapters are earth grounded and have proprietary integrated difference and common mode surge protection, making them ideal for use in outdoor settings.

 

RoHS compliant PoE injectors

 

Ubiquity networking and Power over Ethernet equipment have a declaration of conformity that includes the Restriction of Hazardous Substances Directive (RoHS). This EU legislation is concerned with the use of hazardous materials like lead in electrical and electronic equipment.

 

Why are PoE injectors important?

 

Key advantages of using a PoE injector kit

 

These small, low-profile PoE devices are a convenient solution for adding PoE devices to an existing Ethernet network. They mean that a non-PoE switch does not have to be replaced, saving money.

 

PoE injectors and midspans allow devices to be installed in awkward, inaccessible areas which may lack a power outlet. Wiring a new outlet no only requires time and cable but also the services of a qualified electrician. PoE adapters are plug-and-play. Installation is quick and easy and the use of these devices is readily scalable.

 

The power delivered by these midspans is clean and voltage and frequency controlled. By using PoE as a power solution client devices are protected from being overpowered. Ubiquiti PoE adapters and midspans in particular have in-built surge and electrostatic discharge protection to prevent damage to sensitive electronic devices that are connected.

 

Frequently asked questions 

 

What is the best Ethernet cable to use with these PoE injectors?

 

Ubiquiti produces its own proprietary Ethernet cable called ToughCable. This is an industrial standard Ethernet cable that is suitable for outdoor use, including burial. ToughCable is Category 5e, but had superior shielding, making its performance in certain aspects comparable to Cat 6 cable. It is not only suitable for Power over Ethernet but has in-built design features to reduce the risk of Electrostatic Discharge, a common cause of device failure in electronic devices.

 

The category of Ethernet cable is critical for PoE, with Category 5e or Category 6 cable being recommended for most applications. Also, larger diameter solid copper conductors show the best performance for the transfer of power and data.

 

What is LLDP?

 

LLDP stands for Link Layer Discovery Protocol. This is an IEEE developed protocol that allows devices to communicate or display their identity and functionality within a Local Area Network. It has been adapted from standard 802 Ethernet networking protocols that enable devices to be identified on networks, known as Station and Media Access Control Connectivity Discovery.

 

This OSI Layer 2 discovery protocol essentially allows a powering device like an injector and a powered device to recognize one another and their powering requirements. PoE negotiation takes place using LLDP. When enabled, LLDP will enable automatic power configuration. Type 2, 3, and 4 devices tend to utilize this protocol for the initiation of Power over Ethernet. Not all mid-span injectors use LLDP, though it is a standard feature of PSEs.

 

It is vendor-neutral and proprietary versions of this protocol do exist, but LLDP is vital for Power over Ethernet as it allows devices from multiple vendors to operate safely together.

 

In conclusion

 

Power over Ethernet injectors and PoE adapters are an effective solution for providing targeted, high-performance PoE connectivity within an existing wired network. They are highly adaptable devices and when properly matched, allow a diverse range of devices to be included in a LAN and safely powered. Ubiquity PoE injectors deliver outstanding performance, in line with the leading standards and protocols, meaning that they can be integrated into a network with confidence. 

 

Learn more

 

 

standard DC Barrel Connector
POE Injectors / Adapters

Key Features of POE Injectors

  • All of the above POE adapters/injectors are so inexpensive that you can keep spares at little cost.

Power Over Ethernet was first launched by Cisco in 2000. The standards are IEEE 802.3af and IEEE 802.3at. "Midspan" means the same as POE injector: The term "midspan" refers to the concept of putting a POE injector as close as possible to the device being powered, since some voltage is lost in the ethernet cable.

 

What is a Power over Ethernet Injector?

 

Power over Ethernet (PoE) injectors are electronic devices that are capable of transferring direct current power onto Ethernet cable wires for transmission to a wide range of powered devices via an RJ45 port. They are also known as Power over Ethernet adapters as they are used to convert non-PoE networking to having PoE functionality, by providing an appropriate power supply.

 

Power over Ethernet adapters can be connected via RJ45 ports and plugs to standard network switches to provide an inline PoE power supply. They carry a port for AC input power which is used to supply the injector with its source of power. In this arrangement, PoE injectors function as a midspan device. Midspan PoE devices introduce power onto an existing Ethernet connection using an external power source.

 

How do Power over Ethernet Injectors work?

 

A PoE midspan or injector has a power input, data input, and an out that merges the power and data inputs. The two inputs are converted into a powered output of appropriate voltage and current for the client device. An alternating current (AC) input is also converted to DC, suitable for Powered Devices.

 

About Power over Ethernet

 

Power over Ethernet is a technology that is able to deliver DC power to devices over Ethernet networking cable. This is achieved by using two or four of the twisted pairs that make up Ethernet cable to drive power. The power transfer can take place alongside standard Ethernet data transmission at up to Gigabit speeds with loss of power or performance.

 

Power over Ethernet networking has been standardized by the Institute of Electrical and Electronics Engineers as part of its 802.3 series of standards. Standards were first introduced in 2003 to address the ad-hoc and variable performance of power injector technologies. Currently, there are three key PoE standards released by the IEEE and in widespread use. Recent releases have increased the power available to devices through this technology to over 100 watts. Our selection of Power over Ethernet adapters and injector kits conform to one or more of these key networking protocols:

 

[A] IEEE 802.3af

 

This is the original standard for Power over Ethernet and defines all the basic principles of endspan and midspan powering of devices. This version of PoE, released in 2003, specifies power delivery at a level of 15.4 watts of DC power (44 volts, 350 milliamps per powered twisted pair) that is transferred over 2 of the four twisted pairs within an Ethernet cable. Due to heat dissipation, the minimum power delivered to devices is 12.95 watts. This IEEE standard sets out key strategies that are used by this technology to ensure that power transfer is safe. Power Supply Equipment (PSE) and Powered Devices perform a handshake before the power transfer commences and strict connect/disconnect protocols are initiated. Within this form of PoE, there are sub-levels of power, with PSEs able to negotiate the level of power supply across 3 power class levels (1-3). Devices powered by this form of PoE are known as Type 1 devices and include devices like VoIP phones. It can be run on Category 3 and category 5 cables.

 

[B] IEEE 802.3at

 

This is the second release Power over Ethernet standard known as PoE+. It specifies power delivery over two of the four twisted pairs. PoE+ delivers power at a higher wattage than standard PoE with a maximum power of 30 watts (voltage of up to 57 volts and current of 600 milliamps per twisted pair). Devices that are powered by PoE+ are known as Type 2 devices and include access points and IP cameras. PoE+ is delivered over Category 5 Ethernet cables. PoE+ can be delivered at one of four 0.1 watts stepped power class levels (1-4) negotiated between the PSE and PD.

 

[C] IEEE 802.3bt

 

This is the most recent Power over Ethernet standard, released in 2018. 802.3bt also known as PoE++ delivers a much higher level of power to devices, up to a maximum of 100 watts. PoE++ is distinct from previous versions of PoE as power is delivered over each of the 8 wires within an Ethernet cable. For this reason, it is also described as 4 pair Power over Ethernet (4PPoE).

 

PoE++ is delivered at two rated power levels according to the powered devices served.

 

  • Type 3 devices: deliver maximum power of 60 watts, (usually 51 watts received at the device) with a voltage range of 50 to 57 volts and current of 600 milliamps per twisted pair. Type 3 PoE can be run on Category 5 Ethernet cable. This form of PoE++ can be delivered by signature at one of 6 power class levels (1-6).

  • Type 4 devices: delivers a maximum wattage of 100 watts (71 watts received at the powered device), the highest level of power currently available. The voltage range is 41 to 57 volts and the maximum current on each twisted pair is 960 milliamps. Type 4 PoE has 8 power class levels (1-8).

 

In addition to these standards, PoE injectors deliver power according to a specific mode. The mode refers to the pin assignment mode of the Power over Ethernet mechanism used.

 

  1. Mode A has power delivery over the data pairs of the 4 pairs of Ethernet cable. This corresponds to pins 1 and 2, and 3 and 6 in a 48VDC free polarity arrangement. This mode is used in 10 and 100BASE-TX Ethernet networking with power and data being transferred over two pairs.

  2. Mode B delivers power on the spare twisted pairs in a cable leaving the data pairs free. Pins 4 and 5 (+) and pins 7 and 8 (-). This mode can also be used with 10 BASE-T of 100 BASE-TX

  3. 4 pair transmission mode use all 8 pins for power delivery. The phantom technique is used to delivered power and data simultaneously on all four pairs by exploiting the difference in characteristic frequency of the data and DC power, so they can be separated by the receiving device. This form of transmission is used with Gigabit Ethernet networking 1000 BASE-T.

 

Other features of PoE adapters

 

  • Active vs. Passive PoE Injector

 

PoE is still a very mixed market and not all PoE injectors conform to standards or use certified ports.

 

Active PoE injectors are those that comply with any of the IEEE standards 802.3af, 802.3at, and 802.3bt. The critical feature with these PoE protocols is that a handshake must take place between power sending and receiving devices. Power will not be delivered if the injector is not acknowledged by the receiving device. This makes PoE safer for equipment.

 

Passive PoE injectors do not conform to any of the recognized standards meaning that certain aspects of their safety and performance are not assured. In particular, power may be driven to devices without confirming that it is required or suitable. The power supply cannot be marched or negotiated. Devices can also be over or underpowered causing equipment malfunction or damage.

 

Our range of active Power over Ethernet injectors comply fully with the IEEE standards and provide additional safety and performance benefits for powering devices.

 

  • 12V versus 24V versus 48V PoE Injector

 

PoE injectors are usually one of these voltages, and the injector should be matched to the voltage of the device it will be powering. If there is a significant discrepancy in voltage, a step-down adapter can be used to correct the output voltage.

 

  • Number of output ports

 

Depending on the input power and dimensions of the injector, it may carry more than one PoE output port (e.g 4-port or 8-port PoE injectors). If multiple ports are needed a PoE switch may be a more convenient solution.

 

Ubiquiti PoE injectors and adapters for Power over Ethernet

 

Ubiquiti® PoE injectors are high-specification PoE adapters that can power a range of Ubiquiti devices as well as non-Ubiquiti equipment in accordance with IEEE standards. The range of PoE adapters is broad and spans all power levels.

 

These injectors carry input/output RJ45 ports as well as a socket for 100/240-volt mains power to supply the injector. The input comes from the non-PoE networking equipment and the output drives power to a downstream PD.

 

The Ubiquiti range of PoE injectors delivers DC power at 15 to 54 volts. Current is supplied up to a maximum of 1.5 amps depending on the specific injectors’ specifications. Adapters will either use mode A or B with two pair powering, or power delivery across all four cables.

 

The adapters are earth grounded and have proprietary integrated difference and common mode surge protection, making them ideal for use in outdoor settings.

 

RoHS compliant PoE injectors

 

Ubiquity networking and Power over Ethernet equipment have a declaration of conformity that includes the Restriction of Hazardous Substances Directive (RoHS). This EU legislation is concerned with the use of hazardous materials like lead in electrical and electronic equipment.

 

Why are PoE injectors important?

 

Key advantages of using a PoE injector kit

 

These small, low-profile PoE devices are a convenient solution for adding PoE devices to an existing Ethernet network. They mean that a non-PoE switch does not have to be replaced, saving money.

 

PoE injectors and midspans allow devices to be installed in awkward, inaccessible areas which may lack a power outlet. Wiring a new outlet no only requires time and cable but also the services of a qualified electrician. PoE adapters are plug-and-play. Installation is quick and easy and the use of these devices is readily scalable.

 

The power delivered by these midspans is clean and voltage and frequency controlled. By using PoE as a power solution client devices are protected from being overpowered. Ubiquiti PoE adapters and midspans in particular have in-built surge and electrostatic discharge protection to prevent damage to sensitive electronic devices that are connected.

 

Frequently asked questions 

 

What is the best Ethernet cable to use with these PoE injectors?

 

Ubiquiti produces its own proprietary Ethernet cable called ToughCable. This is an industrial standard Ethernet cable that is suitable for outdoor use, including burial. ToughCable is Category 5e, but had superior shielding, making its performance in certain aspects comparable to Cat 6 cable. It is not only suitable for Power over Ethernet but has in-built design features to reduce the risk of Electrostatic Discharge, a common cause of device failure in electronic devices.

 

The category of Ethernet cable is critical for PoE, with Category 5e or Category 6 cable being recommended for most applications. Also, larger diameter solid copper conductors show the best performance for the transfer of power and data.

 

What is LLDP?

 

LLDP stands for Link Layer Discovery Protocol. This is an IEEE developed protocol that allows devices to communicate or display their identity and functionality within a Local Area Network. It has been adapted from standard 802 Ethernet networking protocols that enable devices to be identified on networks, known as Station and Media Access Control Connectivity Discovery.

 

This OSI Layer 2 discovery protocol essentially allows a powering device like an injector and a powered device to recognize one another and their powering requirements. PoE negotiation takes place using LLDP. When enabled, LLDP will enable automatic power configuration. Type 2, 3, and 4 devices tend to utilize this protocol for the initiation of Power over Ethernet. Not all mid-span injectors use LLDP, though it is a standard feature of PSEs.

 

It is vendor-neutral and proprietary versions of this protocol do exist, but LLDP is vital for Power over Ethernet as it allows devices from multiple vendors to operate safely together.

 

In conclusion

 

Power over Ethernet injectors and PoE adapters are an effective solution for providing targeted, high-performance PoE connectivity within an existing wired network. They are highly adaptable devices and when properly matched, allow a diverse range of devices to be included in a LAN and safely powered. Ubiquity PoE injectors deliver outstanding performance, in line with the leading standards and protocols, meaning that they can be integrated into a network with confidence. 

 

Learn more

 

 

standard DC Barrel Connector