Andy Kunz (Spektrum Dev Team): «[iPhone telemetry] It makes it possible to have telemetry with ANY JR or Spektrum DSM2/DSMX aircraft transmitter (also works in Marine mode) [...] It uses a dongle that plugs into the iPod/iPhone/iPad to receive the data [...] It's pretty slick. No laptop needed, and naturally has access to all those fancy Apple features. Instead of having it in the pits on your bench, you can have it in your chest pocket or your buddy can watch your vitals for you. No more need to try to read the DX8 display while you're flying, the answers are in his hand.»
Spektrum DX8 & DX10 - Page 252 - RC Groups 