What is a PoE injector? The advantages and types of PoE injectors

PoE (Power over Ethernet) refers to an Ethernet power supply technology that transmits both power and data through twisted-pair cables. The application of this technology can effectively enhance network stability and flexibility, thus gaining widespread popularity. Currently, there are various applications based on PoE technology on the market, such as PoE modules, PoE injectors, and PoE splitters, etc.

I. What is a PoE injector?

A PoE injector, also known as a midspan, PoE charger, or PoE adapter, works by connecting non-PoE switches and PoE powered devices (PD) through network cables. This device is typically used in places where low-power terminal devices need to be installed but there are no power sockets available. This solution effectively enhances network flexibility at a low cost, allowing device installation to be less restricted by location and existing network architecture.

II. The advantages of PoE injectors are mainly reflected in the following aspects:

Easy installation: Simply connect the injector to the PoE terminal device and the switch to provide power and data transmission support.

Easy expansion: It can inject power signals into the data signals output by non-PoE switches through network cables, thereby providing both power and data transmission support to the powered devices, bringing more convenience to device connections.

Cost savings: The use of PoE injectors can effectively utilize existing equipment and retain the original network architecture, thereby significantly reducing costs.

Safe and reliable: Dynamic power allocation avoids overloading, supports remote power management, and reduces the complexity of operation and maintenance.

III. Types of PoE injectors

Standard PoE injectors and non-standard PoE injectors

Standard PoE injectors refer to those that comply with PoE industry standards (such as IEEE802.3af, IEEE802.3at, or IEEE802.3bt standards). Under the 802.3af, 802.3at, or 802.3bt PoE industry standards, PoE Power Sourcing Equipment‌ (PSE) and powered devices (PD) automatically negotiate when connected. Only when both ends of the devices comply with the same standard mode can the negotiation be successful. After the successful negotiation between the two ends of the devices, the Power Sourcing Equipment‌ will supply power to the powered device. Under this standard PoE technology working mode, the safety of PoE devices can be effectively guaranteed. Generally, the power supply voltage of 802.3af, 802.3at, or 802.3bt standards is 44-57V (DC).

Non-standard PoE injectors generally refer to those that do not comply with any PoE industry standards (such as IEEE802.3af, IEEE802.3at, or IEEE802.3bt standards). If the voltage values of the two connected devices do not match, it may cause permanent damage to the devices.

In addition to the two major types of PoE injectors mentioned above, PoE injectors can also be classified according to the number of ports, such as single-port PoE injectors and multi-port PoE injectors, etc.