SG200-26P Passive POE

[GQuack]

Greetings, I am a homeowner with 2 SG200-26P switches which are working very well for me. I just purchased a wireless monitoring kit for our home generator which contains two passive POE wireless access points, one connected to the network and one to the generator. Each access point requires a 12V-15V power supply either via an adapter plugged into an 120 outlet (network side) or connected to the generator battery.

I am trying to figure out if I can configure the switch to force the POE port to supply POE power even if the switch doesn't detect the access point. I understand there is a difference between enabling the port for POE which I've done but if the port doesn't even see the passive access point, there is no negotiation, etc. So far I was forced to use the 120 outlet adapter to supply power but is there a way to configure the switch to send power on a POE port even if it doesn't see a POE device on the end?

Thank you in advance for any comments.

[pieterh]

sorry just read up on passive PoE, my previous text does not apply.

[pieterh]

look at this info from Netgear

Passive PoE usually refers to any device using PoE that is not 802.3af or 802.3at.  This includes devices such as cameras and radio antennas that run on 24V PoE.  Passive PoE does not perform a handshake, so it is extremely important to know what PoE voltage your device requires before plugging in the Ethernet cable and powering it up. If you connect the wrong voltage you may cause permanent electrical damage to the device.

so I would not count on getting it to work because 802.3af or 802.3at is based on 48-53V.

maybe you can search for a 802.3at/at to Passive PoE Converter 

[Mohamed Alhenawy]

Hello ,

good day

I thinks there one command #   power inline auto max (...) and you can choose the one you want

try to check that under the interface

[pieterh]

yes you are able to set limits, power is regulated in Watts not in Volts

look at the document Power over Ethernet (PoE) Power Requirements FAQ

I read: it is not possible to disable negotiation of PoE power requirement

you can switch it off or on and on means negotiate

[Mohamed Alhenawy]

I have read the file and agree with pieterh

Disable # no power efficient-Ethernet

Enable # power efficient-Ethernet

[GQuack]

Thank you all for your helpful comments. I've read the document cited by pieterh and this paragraph below in particular seems to apply. I've also reviewed the documentation available regarding the wireless access points and I see no reference to 802.3af compliance anywhere. Looks like I am out of luck and need to stick with the provided power adapter.

Q. Can a Cisco switch be forced to provide pre-standard PoE to an 802.3af-compliant IP phone?

A. There is no way to force the switch to provide pre-standard PoE, because the power allocation is done automatically through negotiation.

Cisco switches with PoE capability automatically supply power to connected pre-standard powered devices, such as Cisco IP phones and Cisco Aironet access points, and to IEEE 802.3af-compliant powered devices if the switch senses that there is no power on the circuit. This means the switch supplies power to any non-Cisco device that does not have Cisco Discovery Protocol (CDP), as long as it is an IEEE 802.3af-compliant powered device.

In conclusion, Cisco pre-standard PoE devices and 802.3af-compliant devices work accordingly, and the switch cannot provide either pre-standard PoE to an 802.3af device or 802.3af power to a Cisco pre-standard device.

From access point documentation:

 

Wireless Access Point Specifications

• Environmental specifications:
  • Operating temperature: --20 to 70_C (--4 to158_F)
  • Storage temperature: --30 to 80_C (--22 to 176_F)
  • Humidity: 10% to 95% non-condensing
  • RoHS compliant Physical Specifications
  • L x W x H: 228 x 64 x 61 mm (9 x 2.5 x 2.4 in.)
  • Weight: less than 400 grams (14 ounces)
  • Enclosure: IP55 rateplastic RF Frequency:
  • USA (FCC): 2.412--2.462 GHz (Channels 1--11) Europe (ETSI): 2.412--2.472 GHz (Channels 1--13)
  • IEEE 802.11gn HT40 ISM Band:
  • USA: 2.422--2.452 GHz (Channels 3--9)
  • Europe: 2.422--2.462 GHZ (Channels 3--11)
• Regulatory Compliance: FCC Part 15, CE EN300 328, EN301 489--1/17, EC60950
• Standards Compliance: TEEE 802.11b/g/n, WiFi Certificate
• Electrical Specifications:
  • Power requirements: 12 VDC @ 1A (switching)
  • PoE: Passive 12V PoE Power consumption: ≤900 mA@ 12 VDC
• LEDs for power and network connection status