Before M$ bought it out, Skype worked fine on my Philips VOIP8551B DECT/Skype phone.
But there was a background buzz on the old ADSL-connected landline, so I stopped using it. However, I recently tried again now that my Internet and phone are independent and the DECT phone is connected to the WLAN router using an Ethernet bridge - and the background buzz on landline has now gone.
Skype works OK, except that some change which M$ made to Skype software means that Skype contacts cannot now be saved to the phone's contact list, whereas previously there was no problem. So, for example, instead of going to the contact list and selecting 'TEST', I now have to dial 'echo123', which is a bit of a pain. Alternatively, contacts can be recalled from 'history'.
Philips are aware of this, as are M$. But Philips blame M$ as they claim that M$ will not allow Philips to make the necessary software changes and M$/Skype now state that the VOIP8551B is 'not supported'.....
Typical M$ behaviour, but it also means that I'll never buy another Philips product, if that's the extent of their customer support.