Information post really.
I had a customer that had to use 4 port PoE switches under their desks as they did not have enough outlets in the building. They had 6930 phones with the integrated DECT headset. They had lots of voice issues and phones would randomly stop responding etc. It turns out that with the integrated DECT headset the device needs PoE+ (802.3at), replaced the switches with PoE+ and all good!
Cheers,
Belsden