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We are planning to buy a new switch, we have few access points with the POE+ logo on their Ethernet ports, when surveying the market for the switches we also found multiple switch models some have POE ports and others have POE+ ports. This left us wondering, if we bought switch that only has POE ports, would it be able to power up our POE+ access points?

  • Depends on the vendor/model of the access points. Some won't work, some will work with reduced functionality or performance. You would really need to provide that vendor/model of the access points to get an actual answer. – YLearn Jul 14 '15 at 18:31
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No a POE switch does not deliver enough power to run a POE+ device.

Having plugged a Cisco 1500 AP into a normal poe switch and then struggling for a day to get a ptp link-up I can say first-hand that it is a bad idea.

The device booted up and I could log in but the Radio was stuck in reset, thinking it was a config or antenna problem, I wasted a lot of time, before finding the small message in the log, that there was not enough power to powerup the wifi module.

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The similar question was asked and answered in detail here:

POE, POE+, UPOE

You have to check what's the actual requirement of device, aside the name "PoE+". The specific information about power requirement and capability to gracefully degrade service (offer less throughput in case of APs, or less power to antennas) should be clearly documented in the device technical documentation.

  • The AP datasheet says Maximum Power 24w, that's 9w more than POE supply, but again it says "Maximum", what is the norm operation wattage? we don't know, this is what is causing the confusion. – Sisyphus Jul 14 '15 at 17:23
  • As Lukasz said, most of the APs accepts POE and POE+. In a very simplified scenario where you have an AP with POE+ powered with only POE, the AP only works with half the antenas. This means that you only could achieve half maximum speed of the wifi. My suggestion is to read your AP Datasheet and check behavior with POE and POE+. – KorXo Jul 14 '15 at 17:53
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PoE (802.3af) provides up to 15.4W power. PoE+ (802.3at) provides up to 25.5W power. How much power does your device need? https://en.wikipedia.org/wiki/Power_over_Ethernet

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