[Vertigo]

A complementary device enhancement known as simultaneous 1X Voice and EV-DO Data (SVDO) will also become available during the same timeframe and will enable CDMA2000 devices to access EV-DO packet data services while in an active 1X circuit-switch voice call. For example, users will be able to send emails or access the Web while on voice calls; phones with GPS can update maps or download real-time traffic information while on voice calls, etc. This device enhancement, which enables these concurrent voice and data services, is independent of the air link standard and infrastructure.

http://cdg.org/news/press/2009/Aug17_09.asp