Odd POE Failure on 5520-48T-PWR

[eangulus]

Hi,

Just trying to get some insight.

We have a stack of 6 5520-48T-PWR switches running 6.3.6 firmware.

To that, we have a number of POE Cameras and POE Cisco SPA504G phones. THis is all connected to a 5130 UPS with an extended battery. With servers and NAS, this runs the whole rack for 40min no problem.

The issue I am having thou is that when UPS kicks in due to an outage or even just a power flicker, instantly the Cisco phones reboot. The Cameras stay running. The switch never reboots. Everything else is fine. The 5130 switch rate is 1.4ms. It is instant and reproducible.

I have set the POE ports to Critical to see if that fixed it but it didn't. Not sure what the real cause is and therefore have no idea how or even if it can be rectified.

Any ideas for me to test and try?

[pat2012]

What brand of UPS is the 5130?  Sounds like Eaton/Powerware.  A 1.4 ms switch-over shouldn't cause the phones to reboot.

Do the phones have PCs connected to them?

Besides the usual, "upgrade to the latest supported firmware", I would suggest you change the UPS to an "online" model.  The Eaton 9PX or Liebert GXT4 series.

Also.  Have the electrical system in the building thoroughly checked - ground loops, open ground etc.