Handheld Iridium Satellite PTT Radio with Global Coverage. SATELLITE PTT (Push-To-Talk) is a two-way radio system that uses the Iridium® satellite network. It can be used as a communication tool in remote, isolated areas where there are no mobile phones or landline network infrastructure. Even if terrestrial network infrastructure is rendered unusable by human or natural disasters, SATELLITE PTT can provide a stable back-up, independent from other networks. One-to-Many Communications: Unlike satellite phones, IC-SAT100 users can immediately start talking to all the radios in the same talk-group, with just a push of the transmit (PTT) button.