PoE (Power over Ethernet) technology revolutionizes the way power and data are transmitted over Ethernet cables. It enables Power Sourcing Equipment (PSE), such as a PoE switch, to deliver power and data simultaneously to Powered Devices (PD), including IP cameras and VoIP phones. This integration simplifies cabling installation, eliminates the need for separate power cables, and reduces overall costs.

To regulate the power delivery to PDs, the Institute of Electrical and Electronic Engineers (IEEE) has established various PoE standards, including IEEE 802.3af, 802.3at, and 802.3bt. These standards define the maximum power that PSEs can provide and the power requirements for PDs.

Let's delve into the details of these PoE standards and their associated wattage.

PoE Standards Introduction

PoE standards encompass three main types: IEEE 802.3af, IEEE 802.3at, and IEEE 802.3bt. These standards establish the minimum power that Power Sourcing Equipment (PSE) can provide and the maximum power that Powered Devices (PD) can receive.

Understanding PoE Wattage

As previously explained, IEEE 802.3af provides a maximum power output of 15.4W per port, while PoE+ (IEEE 802.3at) supports up to 30W. However, when connecting multiple devices to a single PoE/PoE+ switch, it becomes crucial to ensure that the combined power requirements of these devices do not exceed the maximum power wattage supported by the switch. This ensures that the switch can reliably provide sufficient power to all connected devices without overloading its capacity. Careful consideration and planning are necessary to avoid exceeding the switch's power limitations and maintain stable operation.

For example, let's take the LINOVISION POE-SW708GM-DC12V, a managed PoE++ switch with 8 RJ45 ports and 2 SFP ports. Compliant with IEEE 802.3af/at/bt standards, this switch has a total power budget of 240W. This means it can concurrently power 8 devices compliant with PoE+ standards (30W x 8 = 240). It can also support 8 devices compliant with PoE standards (15W x 8 = 120W).

However, there is no need for concern as modern network switches are designed to be intelligent. When a device is connected, the switch automatically detects whether it is compatible with PoE or PoE+. If the device requires a low power of 5W, the switch supplies exactly that amount. If the device demands a higher power of 20W, the switch adjusts accordingly. And if you connect a device without PoE capability, rest assured that the switch will provide data transmission only.

How Much PoE Wattages are Need?

The power needs of your devices depend on what you're connecting. Most devices, such as security cameras, IP phones and standard wireless APs, require no more than 30 watts.

However, certain devices, such as 802.11ac wireless access points with multiple USB ports and radios, may require over 30 watts for optimal performance. In such cases, PoE++ or PoH switches are the ideal solution. It's worth noting that some devices can adapt to lower power availability by using fewer radios or disabling certain features.

Linovision Managed Switches: Your PoE Solution

At Linovision, we offer a range of PoE/PoE+/PoE++ switches that comply with the PoE standards, providing enhanced security and improved capabilities. These switches are available in 4,5,8 and 48 port options. They support layer 2+ switching features like VLAN and offer advanced management options such as WEB, CLI, TELNET, and SNMP. FS PoE/PoE+ switches can power any 802.3af or 802.3at compliant device on the market, providing flexibility and security. The table below provides specifications for four of our PoE/PoE+/PoE++ switches:

Summary

It is essential to have a clear understanding of PoE standards and wattage to ensure effective device connections. By aligning your devices' power requirements with the appropriate PoE standard, you can ensure smooth and reliable operation. PoE technology simplifies complex cabling setups and offers flexibility in power delivery.