Just off the phone (21 November 2006) with Jeff Black, ceo of TalkPlus and star of the demo I posted 13 November 2006: calling from a mobile to echo123 without a Skype client anywhere in the loop.

He confirmed:

1. TalkPlus does not use SkypeIn.
2. TalkPlus does not use SkypeOut.
3. TalkPlus does not use the Skype-operated SIP gateways now.
4. TalkPlus conversations going from a mobile to a Skype user are only encrypted in the usual Skype way from TalkPlus's servers to the Skype client.

Black said he's been to Skype's London's headquarters several times, most recently about 30 days ago. He said they fully shared what TalkPlus does and how it does it to Skype's management and technical people, right down to engineering diagrams. They continue friendly discussions. He said TalkPlus filed multiple patents which predate Skype on mobiles.

Black declined comment when asked if TalkPlus was building something for Skype.

If you'd like to chat about this, join the Skype 3.0 discussion. You can view the video of the demonstration on Revver, Vox, and Google Video.