That's the crux of the article -- the sip in question is inbound sip -> gv #...

		wiredfool on March 7, 2011 \| parent \| context \| favorite \| on: Google Voice Now Offers SIP Addresses For Calling ... That's the crux of the article -- the sip in question is inbound sip -> gv # -> PSTN not sip client <-> gv <-> world And at length, linked from the article: http://blog.duh.org/2011/03/so-google-voice-sip-is-actually-...