As I am wading into this sort of comms i came across the below info and thought I would pass it along. Product Documentation PDF: Direct Talk (MotoTalk) Fact Sheet PDF Direct Talk Instructions PDF I570 Users Guide PDF YouTube Videos Explaining iDEN Radios: SHTF Comms - i355 Pt1 SHTF Comms - i355 Pt II Secure Communication during the SHTF SHTF COMMS - i355 - Extra | 6dB gain Omni Test