PoE adaptor (also name PoE injector) is a product which can send power and data through single Cat 5e/Cat 6 to remote powered devices. The PoE adaptor provides power solution to a wide range of network equipments such as IP cameras, access point and VoIP phone. Due to transparency to TCP/IP protocols, no configuration is required. The PoE adapter is a plug and play product.
PoE adaptor has different types based on power voltage. There are 12V/24V/48V adaptor. 12V PoE adaptor is the most primitive adaptor. As we know, an Ethernet cable has four twisted pairs. Two of the pairs are used for data delivery, and the spare pairs sent power to remote devices. No protection protocol is used in this type of adaptor. When the 12V adaptor is powered, electricity will be sent directly to PoE devices. Usually there is passive splitter at the other end to separate the power for remote device. As the voltage will drop down sharply while the distance is increasing, the 12V PoE adaptor can only be used in the short distance transportation.
Another type of PoE adaptor, 24V adaptor, can supply more power to devices. The DC24V injects the power to the Ethernet cable and the DC12V regulator is required at the remote device in order to output correct voltage. 24V adaptor sends power to 50 meter far. Voltage drop is being taken care of by the voltage regulator.
The last type of PoE adaptor is 48V adaptor. Before introducing the 48V PoE adaptor, one point should be known. That is passive and active PoE adaptor. Non-standard adaptor has no built-in PD signature detection. The adaptor will release DC48V directly when the powered device is plugged in at the end of RJ45 connector. The standard PoE adaptor will verify the remote device before adding the power to the Ethernet cable. The PD signature guarantees the safe process for power over Ethernet solution. Signature detection can avoid the device burned out and protect from the power surge. If the powered device fails to be verified as standard PoE devices, the adaptor will stop the power.
12V PoE adaptor can be used in 12V IP access point and other low voltage devices in short distance. A passive splitter is needed to split the power from the data. As no protection is added, you must have basic knowledge about how to operate the passive PoE adaptor. If you mix up with the twisted pairs, the remote device will be damaged immediately. The 24V PoE adaptor usually works with specific products. The regulator has to be included inside to convert to DC12V. It is better to limit the distance to 50 meters because of the voltage drop. The standard 48V PoE adaptor complies with the IEEE 802.3 specification. As long as the powered device also meet IEEE802.3 standard, the solution is plug and play. The adaptor can deliver data and power up to 100 meters.
To learn more about PoE adaptor or injector, check how to choose the right PoE injector for your network.