What type of circuit is Iridium?

• A. Government-owned, terrestrial-based, providing secure voice only
• B. Public switched telephone network
• C. Terrestrial microwave link
• D. Commercially operated, satellite-based, providing secure/non-secure voice and data

Answer: (D)

Iridium is a commercially operated, satellite-based communication system that provides both secure and non-secure voice and data globally. It uses a constellation of satellites in low Earth orbit to maintain coverage anywhere on the planet, including oceans and remote regions where terrestrial networks don’t reach. This sets it apart from government-owned, land-based secure voice networks, the public switched telephone network (landlines), or terrestrial microwave links (which rely on fixed ground towers and line-of-sight). The key idea is that Iridium’s strength comes from being a satellite-based system run commercially, capable of handling diverse voice and data needs on a global scale.