Thiết bị cấp nguồn (PSE) đầu cuối so với thiết bị cấp nguồn (PSE) trung tâm: Tìm hiểu về Thiết bị cấp nguồn cho PoE

In Power over Ethernet (PoE) technology, Thiết bị cung cấp điện (PSE) plays a central role by delivering both data and electrical power over a single Ethernet cable.
Depending on where the power is injected into the network, PSE devices fall into two categories: Endspan PSE and Midspan PSE.
Understanding their differences is essential when designing or deploying efficient PoE networks.

1. What Is Endspan PSE?

Endspan PSE, often referred to as a PoE switch, integrates power injection directly into the network switch itself.
Each Ethernet port on the switch is capable of delivering both data and DC power to Powered Devices (PDs) such as IP cameras, điểm truy cập không dây (WAP), and VoIP phones.

Đặc điểm chính

• Integrated within the switch hardware

• Transmits both data and power through the same RJ45 port

• No additional PoE injector required

• Follows IEEE 802.3af / 802.3at / 3bt tiêu chuẩn

• Simplifies wiring and reduces points of failure

Ưu điểm

• Simplified setup—only one device needed

• Lower power loss due to direct integration

• Easier centralized management of network power

Ví dụ:
An enterprise-grade PoE+ switch that powers 24 IP cameras simultaneously is a typical Endspan PSE device.

2. What Is Midspan PSE?

A Midspan PSE—commonly known as a PoE Injector—is an external device positioned between a non-PoE switch and the PD.
It adds electrical power to the Ethernet cable without affecting the data signal.

Đặc điểm chính

• Hoạt động với các bộ chuyển mạch cũ hoặc không hỗ trợ PoE

• Inserts DC power into Ethernet cables mid-path

• Usually available as single-port or multi-port injectors

• Compliant with IEEE PoE standards for safety and compatibility

Ưu điểm

• Enables PoE support on existing network infrastructure

• Cost-effective for upgrading specific ports or small systems

• Flexible deployment—no need to replace existing switches

Ví dụ:
A single-port PoE injector powering an outdoor wireless AP from a standard Ethernet switch is a Midspan PSE setup.

3. Technical Comparison: Endspan vs. Midspan

Đặc tính	Endspan PSE (PoE Switch)	Midspan PSE (PoE Injector)
Vị trí	Integrated in the switch	Between switch and PD
Chức năng	Provides data + power	Adds power only
Cài đặt	One device	Requires extra hardware
Trường hợp sử dụng	New PoE infrastructure	Upgrading existing networks
Hiệu quả	Cao hơn	Slightly lower (additional conversion)
Các thiết bị điển hình	PoE switches	PoE injectors, hubs
IEEE Compliance	802.3af / 802.3at / 802.3bt	802.3af / 802.3at / 802.3bt

Both PSE types serve vital roles.
Endspan PSE is ideal for large-scale, centralized PoE networks, while Midspan PSE offers flexibility and retrofit compatibility in mixed environments.

4. Power Delivery and Safety Mechanisms

Regardless of type, both Endspan and Midspan PSE devices follow the same PoE power negotiation process defined by IEEE standards:

1. Detection: Identify whether a connected device supports PoE.

2. Classification: Determine the PD’s required power level (Class 0–8).

3. Power Application: Deliver DC power using Mode A (data pairs) or Mode B (spare pairs).

4. Monitoring: Maintain voltage and current stability during operation.

5. Shutdown: Automatically cut power when faults or disconnections occur.

This ensures that non-PoE devices are never damaged, and all PDs receive stable, compliant power.

5. Practical Applications

• Endspan PSE:

  • Data centers and enterprise networks

  • Security surveillance systems

  • Smart building automation

• Midspan PSE:

  • Upgrading legacy switches to support PoE devices

  • Remote or temporary installations

  • Công nghiệp IoT setups where power sources are limited

6. LINK-PP Solutions for PSE Equipment

LINK-PP provides a full range of PoE-ready magnetic RJ45 connectors and Bộ biến áp Ethernet designed for both Endspan and Midspan PSE implementations.

Ví dụ:

• LPJ0123GDNL — A compact PoE+ RJ45 connector supporting IEEE 802.3at (PoE+), ideal for PoE switches (Endspan PSE).

• LP41223NL — A 10/100Base-T PoE+ LAN transformer that ensures high isolation and efficient power delivery for injectors (Midspan PSE).

• LPJK6071AONL — A Gigabit magnetic module for 1000Base-T applications with PoE++ support, suitable for industrial-grade PSE designs.

These components are engineered for độ toàn vẹn tín hiệu, thermal stability, and long-term reliability, ensuring optimal performance in both PoE switches and injectors.

7. Choosing the Right PSE Type

Khi lựa chọn giữa Endspan and Midspan PSE, consider:

• Network scale: For large or new installations, choose Endspan.

• Legacy integration: For existing non-PoE switches, Midspan is cost-effective.

• Power requirements: High-power devices (e.g., 802.3bt Type 4) may require advanced PSE modules.

• Environmental conditions: Select PoE connectors and transformers with industrial temperature ratings for rugged environments.

Kết luận

Both Endspan PSE and Midspan PSE are essential components in modern PoE infrastructure.
Trong khi Endspan tích hợp việc cung cấp điện và dữ liệu trong một thiết bị duy nhất, thì Midspan mang lại tính linh hoạt để nâng cấp các mạng không hỗ trợ PoE mà không cần thay thế toàn bộ phần cứng.

For OEMs and network engineers, choosing reliable PoE-certified components is critical. Explore LINK-PP’s portfolio of Bộ kết nối PoE RJ45 and Bộ biến áp LAN to build efficient, high-performance PSE solutions at l-p.com.