Solution to Connection Failure between PoE Switch and IP Camera

Tag： Blog | 10-05-2025

1、 Basic physical connection troubleshooting (priority operation)

Network cable and interface inspection

Confirm to use unshielded network cables of category 5 and above (cables supporting PoE power supply shall meet CAT5e+standard), and the length shall not exceed 100 meters (upper limit of effective distance for PoE power supply);

Check whether the network cable crystal head is firmly crimped, whether the copper core is exposed, and whether the wire sequence is wrong (standard 568B: white orange orange white green blue white blue green white brown);

Swap the network cable for test (replace it with a known normal network cable), or use the network cable tester to detect whether the cable is connected or disconnected;

Check whether the PoE switch port and the camera network port are oxidized or deformed. Clean the interface by plugging and unplugging the network cable for three times to avoid virtual connection.

Verification of equipment power supply status

Observe the PoE switch port indicator: if the "PoE" light is not on, it means that the port does not output power, and you need to confirm whether the switch supports PoE (external power adapter is required for non PoE switches), and the port is not "PoE disabled" (some switches can power on the port through the Web interface);

Check the power indicator of the camera: if the camera does not have any light, use a multimeter to measure the voltage between the 1/2 (data+) and 3/6 (data -) pins of the network cable crystal head (PoE standard voltage: 44.57V for 802.3af, 50-57V for 802.3at). If there is no voltage, it may be the switch port fault or the camera head does not support PoE;

Confirm PoE power matching: calculate camera power consumption (generally 1080P camera is about 5-8W, 4K camera is about 8-15W), check the upper limit of single port PoE power of the switch (such as af standard single port 30W, at standard single port 30W, bt standard single port 60W) and total PoE power (to avoid power failure of partial ports due to total power overload).

2、 Troubleshooting network configuration

Consistency check of IP address and network segment

Confirm that the camera and the PoE switch (or computer) are in the same network segment: search for devices through camera manufacturer tools (such as "SADP" of Hikvision and "ConfigTool" of Dahua). If not, check whether the computer IP is consistent with the camera's default network segment (most cameras have a default IP of 192.168.1.XX and a subnet mask of 255.255.255.0);

Check the IP address conflict: if the camera is found but cannot be accessed, check whether there is an "IP conflict" prompt in the tool, and modify the camera IP to an unoccupied address in the network segment (for example, 192.168.1.100, which should not be duplicate with the router and other device IP);

Check the gateway and DNS: If the camera needs to access the external network (such as remote viewing), it is necessary to fill in the correct gateway (router LAN port IP) and DNS (such as 8.8.8.8) in the device configuration. The gateway error will cause the device unable to communicate with the external LAN.

Switch and route configuration verification

Confirm that the PoE switch does not enable VLAN isolation: if the switch has VLAN partition, the port where the camera is located should be allocated to the same VLAN as the computer/router, or the VLAN function should be turned off (entry level switches do not have VLAN configuration by default, and enterprise level switches need to log in to the Web interface to check);

Check the router port speed limit/filtering: some routers will restrict the access of unknown devices, and it is necessary to confirm in the router "Device Management" that the camera has been allowed to access, and has not been set bandwidth limit or IP blacklist;

Test switch data forwarding: connect the computer directly to the PoE switch port and ping the camera IP (such as ping 192.168.1.100- t). If the packet loss rate is>0%, it may be the switch port fault or network cable interference. Replace the switch port for testing.

3、 Troubleshooting of equipment and environment

Device hardware fault detection

Cross test to locate the faulty equipment: connect the camera to other normal PoE switches. If it can be started normally, it indicates that the original switch port or the whole machine is faulty; Connect other normal PoE devices (such as wireless AP) to the original switch port. If the device does not work, the switch port is faulty and needs to be repaired or replaced;

Camera restoration to factory settings: If the camera can be powered on but cannot be searched, long press the device reset key (usually a small hole, which needs to be pressed with a toothpick for 10 seconds) to restore the default configuration, clear the wrong configuration and search again;

Check the camera network port failure: use the network cable to directly connect the camera and the computer (skip the switch). If the computer still cannot recognize it, it means the camera network port is damaged. Replace the camera or the external USB to network port adapter.

Environmental interference and compatibility problems

Avoid strong electromagnetic interference: PoE network cable shall be far away from strong current lines (such as 220V power line), frequency converters, motors and other equipment to avoid data transmission interruption caused by electromagnetic interference. If necessary, use shielded network cable (STP) and do a good job of grounding;

Confirm PoE standard compatibility: some old cameras only support 802.3af standard. If 802.3at/bt switches are connected, the ports need to be forced to switch to af mode on the switch interface (some switches are automatically compatible, and some need to be manually set);

Firmware version update: log in to the camera manufacturer's official website, download the latest firmware and upgrade it (through the manufacturer's tools or Web interface), and fix the compatibility bugs in the old firmware (such as communication failure with the PoE switch of a specific brand).