Tag Archives: PoE switch

Can A Computer Connected to the PoE Switch?

PoE switches are commonly used in various networks. It can be low-cost unmanaged edge switches with a few ports or complex multi-port rack-mounted units with sophisticated management. When used in small or home networks, many people may wonder if it can be connected directly with a computer. This post will discuss this question in details.

What Are PoE and PoE Switch

Before the discussion, it is necessary to have a basic understand of what are PoE and PoE Switch:

PoE

As demands for connection from networking devices such as IP phones, IP cameras and access points increase, deployment complexity and cost rise as well. For less cable usage and investment, Power over Ethernet (PoE) technology is developed to provide both data connection and electrical power to devices through just one Cat5/Cat5e/Cat6 cable.

PoE Switch

PoE switch is a network switch that has Power over Ethernet injection built-in, which can transmit both power and data through an Cat5/Cat5e/Cat6 Ethernet cable at the same time. This kind of switch makes it easy for different sectors to deploy powered devices like VoIP phones, wireless access points and IP surveillance cameras in challenging places like ceilings, walls, outdoors, or wherever electrical outlets are not easily available.

poe switch connection

Can A Computer Connected Directly to the PoE Switch?

As shown below,PoE switch usually have the same RJ45 port as a computer. So many people will think they can be connected directly. But do not forget that PoE switch may also transmit electrical power through the RJ45 port and Cat5/Cat5e/Cat6 cable to the computer. Then can a computer be connected directly to the PoE switch? This is largely depend on the switch you have:

poe switch

If you have a PoE switch that conforms to 802.3af (the PoE standard) or 802.3at (the PoE Plus standard) and doesn’t claim to be “passive”, you can definitely connect your computer with it. This is because this kind of PoE switch has the function of PoE detection which is designed to avoid damage to non-PoE devices. In other words, when you connect other network devices to your PoE switch, it will communicate with the these devices whether they need power or not. Power is only injected if and when this negotiation is successful. Ethernet devices such as phones and access points are detected by the switch as accepting PoE and will receive the additional power feature from the PoE switch/port. Whereas a computer and other non-PoE devices will not be detected as having PoE capability and will just use the data communications features of the port.

computer connect to poe switch

However, there exists a class of PoE switches, usually referred to as “passive” or “always on”, which supply power without PoE detection. Why would anyone do this? Because this kind of PoE switch is significantly cheaper. Whether it damages your device depends on the voltage of the passive PoE switch and your devices. For a computer, it may be damaged for excessive voltage or current.

Conclusion

PoE switch is a dedicated device that contains multiple Ethernet ports to provide power and network communications. It is usually used in NVR/IP camera networks. For small or home networks, if you want to connect a computer to the PoE switch, make sure your switch follows the standard 802.3af or 802.3at PoE requirements. So can you connect a computer directly to your PoE switch?

PoE in Enterprise Network

In traditional data communication network, a network connection and a power connection are required. However, with PoE technology, only the ordinary Ethernet network cable is required. PoE (Power over Ethernet) is a technology designed to allow the existing Ethernet network cable to deliver direct electrical current flows. It has a lot of advantages like lower cost, easier maintenance, less down time and great flexibility during management and network installation. A variety of products have been designed to make full use of PoE technology. This post will introduce these PoE based products and how to use them in our network.

PoE switch

PoE switch is the most important device is you are going to use PoE technology. It is the PoE switch that transmission the necessary data and power flow together to other PoE devices. Not all the devices can be powered by PoE switches, as the electrical power provided by a PoE switches is limited. For instance, the IEEE 802.3af guarantees only 12.95 W of power on a given connection. Thus, if your devices required power higher than that, then the PoE cannot work out under this standard. The power that a PoE can provide for connections differs according to the technologies. And the port type and port numbers that PoE switches provided are various. Generally, PoE switches provided in the market can provide SFP ports for uplink and RJ45 ports for downlink. Here offers several different PoE

PoE Switch Port Detail Power Supply for PoE Port Max. Power Consumption
PS130W-8 8 PoE ports, 2 SFP ports 15.4W 130W
PS250W-8 8 PoE ports, 2 SFP ports 30W 250W
PS400W-24 24 PoE ports, 4 SFP ports 15.4W 400W
PS650W-24 24 PoE ports, 4 SFP ports 30W 650W
PS650W-48 48 PoE ports, 4 SFP+ ports 30W 350W

In many public places or even our own houses, camera is installed for surveillance These cameras are usually required to be connected to the Ethernet or monitor. As the power required by camera is not high and the places they deployed are usually lack of power outlet, IP camera which supports PoE is very popular. With a RJ45 port, the PoE IP Camera can be connected to the switch for data communication. The following picture shows a Camera that support both Ethernet network cable and additional power cords.

PoE IP Camera

WiFi is necessary in most places now. In the public places like hospital, hotel, or office, wireless access points are usually installed to transfer the data from Ethernet network cable into WiFi signals. Wireless access point is usually installed on the ceiling, where power outlet seldom installed. Thus, PoE wireless access pointer is a preferred choice in most public places. As wireless access point just needs low voltage power support, the network cable is able to provide enough power that it required.

PoE wireless access point

Network Making Full Use of PoE technology

Telecommunication network using PoE technology has a wide range of applications. It is usually installed at enterprise network like office building. The following picture shows a sample of small network using PoE technology.

PoE network

An 8-port PoE switch is being used to connect devices in a small office. The eight ports of PoE switch are set into support four Non-PoE ports and four PoE port. The devices like laptop and printer required high voltage power supply is connected to the non-PoE ports for data communication. Devices like 300 Mbps wireless access point with PoE function, and two PoE IP cameras that requires low voltage power supply, are connected to PoE port of this switch for both power supply and data communication.

The using of PoE switch, camera, and wireless access point is flexible and convenience. To provide higher speed data transmission and more applications is the trend of PoE devices developing. Meanwhile, the power that these PoE switch can supply is also increasing gradually.