{"id":4001,"date":"2025-10-13T11:12:00","date_gmt":"2025-10-13T11:12:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/glossary\/poe-pse-power-sourcing-equipment-guide\/"},"modified":"2026-06-18T08:36:32","modified_gmt":"2026-06-18T08:36:32","slug":"poe-pse-power-sourcing-equipment-guide","status":"publish","type":"post","link":"https:\/\/lp.szlogic.cn\/ru\/glossary\/poe-pse-power-sourcing-equipment-guide","title":{"rendered":"What Is Power Sourcing Equipment (PSE) in PoE Networks?"},"content":{"rendered":"
\"What<\/figure>\n\n\n\n

Power Sourcing Equipment (PSE)<\/strong> is the device that supplies DC power over Ethernet cabling to a Powered Device (PD)<\/strong> within the IEEE 802.3 Power over Ethernet (PoE)<\/strong><\/a> ecosystem. In other words, PSE<\/strong> is the PoE power-supplying side (the switch or injector that provides power), and PD<\/strong> is the powered endpoint (for example, an IP camera or access point). <\/p>\n\n\n\n

Power Sourcing Equipment (PSE)<\/strong> is the power-supplying side of a Power over Ethernet (PoE)<\/strong> system. It delivers DC power and data simultaneously over standard Ethernet cables\u2014typically through RJ45 connectors<\/strong><\/a>. This technology eliminates the need for separate power lines, simplifying installation and reducing costs in enterprise, industrial, and IoT applications.<\/p>\n\n\n\n

In a PoE (Power over Ethernet) setup, the PSE (Power Sourcing Equipment) transmits power to a Powered Device (PD)<\/strong>\u2014such as an IP camera, wireless access point (WAP), or VoIP phone\u2014through the same network cable used for data transfer.<\/p>\n\n\n\n

➡️ <\/strong>Definition of PSE<\/h2>\n\n\n\n

A PSE (Power Sourcing Equipment)<\/strong> is any network device capable of supplying electrical power through Ethernet cables to PDs that support PoE functionality. It injects power onto the twisted pairs of the Ethernet cable while maintaining data communication integrity.<\/p>\n\n\n\n

In other words, the PSE is the \u201cpower provider,\u201d while the PD is the \u201cpower receiver.\u201d<\/p>\n\n\n\n

➡️ <\/strong>Types of PSE<\/h2>\n\n\n\n

There are two main types of Power Sourcing Equipment, depending on their position in the network:<\/p>\n\n\n\n

\"Types<\/figure>\n\n\n\n
\n\n<\/colgroup>

Type<\/strong><\/p><\/th>

Typical Devices<\/strong><\/p><\/th>

Key Features<\/strong><\/p><\/th><\/tr>

Endspan PSE<\/strong><\/p><\/td>

PoE Switch<\/p><\/td>

Provides power and data directly from Ethernet ports\u2014no additional injector needed.<\/p><\/td><\/tr>

Midspan PSE<\/strong><\/p><\/td>

PoE Injector<\/p><\/td>

Installed between a non-PoE switch and the PD; supplies only power, not data.<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n

Both types are essential for extending PoE capabilities to a wide range of network infrastructures, from legacy systems to modern enterprise deployments.<\/p>\n\n\n\n

➡️ <\/strong>How PSE Works<\/h2>\n\n\n\n

A PSE operates through several precise stages to ensure safe and reliable power delivery:<\/p>\n\n\n\n

    \n

  1. Detection<\/strong> \u2013 Identifies whether the connected device is a valid PoE-compatible PD.<\/p><\/li>

  2. Classification<\/strong> \u2013 Determines the PD\u2019s power class (e.g., Class 0\u20138).<\/p><\/li>

  3. Power Delivery<\/strong> \u2013 Injects DC voltage via Mode A or Mode B wire pairs.<\/p><\/li>

  4. Maintenance<\/strong> \u2013 Monitors current flow and voltage stability during operation.<\/p><\/li>

  5. Disconnection<\/strong> \u2013 Automatically cuts power when the PD is removed or a fault is detected.<\/p><\/li>\n<\/ol>\n\n\n\n

    This intelligent process ensures both equipment safety and network reliability.<\/p>\n\n\n\n

    ➡️ <\/strong>PSE and IEEE PoE Standards<\/h2>\n\n\n\n

    IEEE standards define the output power levels of PSE devices. Each version expands the available power budget and device compatibility:<\/p>\n\n\n\n

    \n\n<\/colgroup>

    PoE Standard<\/strong><\/p><\/th>

    Maximum Power (at PSE)<\/strong><\/p><\/th>

    Common Applications<\/strong><\/p><\/th><\/tr>

    IEEE 802.3af (PoE)<\/strong><\/a><\/p><\/td>

    15.4 W<\/p><\/td>

    IP phones, entry-level access points, and cameras<\/p><\/td><\/tr>

    IEEE 802.3at (PoE+)<\/strong><\/a><\/p><\/td>

    30 W<\/p><\/td>

    Dual-band access points, video devices<\/p><\/td><\/tr>

    IEEE 802.3bt (PoE++)<\/strong><\/a><\/p><\/td>

    60 W (Type 3) \/ 90\u2013100 W (Type 4)<\/p><\/td>

    Industrial gateways, high-power APs, displays<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n

    As PoE standards evolve, PSE technology continues to enable higher-power and more energy-efficient network devices.<\/p>\n\n\n\n

    \"Common<\/figure>\n\n\n\n

    ➡️ <\/strong>Applications of PSE<\/h2>\n\n\n\n

    Power Sourcing Equipment plays a vital role across modern networking environments:<\/p>\n\n\n\n