The core difference between standard PoE and non-standard PoE lies in whether it is "delivering power through negotiation" or "forced power in".
We can think of standard PoE as a "polite butler" and non-standard PoE as a "rude feeder".
Key difference: Whether or not there is a "handshake protocol"
| characteristic | Standard PoE | Non-standard PoE (Passive/Passive PoE) |
| International Standards | Compliant with IEEE 802.3af / at / bt. | There is no unified international standard; it is determined by the manufacturers themselves. |
| Security | Extremely high. Before supplying power, it will first check whether the other party supports PoE. | It's risky. No matter who the other party is, it will discharge electricity immediately upon plugging in. |
| Power supply logic | Test first, then supply power (commonly known as "handshake"). | Forced power supply (Always On). |
| compatibility | It won't damage the network card when plugged into a regular computer's network port. | Plug it into a regular computer's network port, and it may burn out the network card. |
| Voltage | Typically 48V - 57V. | There are many types, with 12V, 24V and 48V being the most common. |
3 practical methods:
If you have a PoE switch or power supply, you can judge its quality from the following aspects:
1. Check the nameplate
Standard: Must be marked with IEEE 802.3af, 802.3at, or 802.3bt.
Non-standard: Usually only PoE is written, or Passive PoE is written.
2. Check the voltage.
Standard: The vast majority of standard PoE is 48V.
Non-standard: If you see a "PoE switch" with a voltage of 12V or 24V, it is 100% non-standard.
Note: There are also non-standard products with 48V, so the voltage should only be used as one of the references.
3. Use a multimeter to measure
Method: Without connecting terminal equipment, after powering on, use a multimeter to measure the power supply pairs of the switch (usually 1/2(+) 3/6(-) or 4/5(+) 7/8(-)).
Standard: No stable voltage can be detected.
Non-standard: Can directly measure stable voltage.
