Always on party line PTT is a very different thing from PSTN voice calling, although some satellite networks do offer the former. PTT is indispensable in a real

Always on party line PTT is a very different thing from PSTN voice calling, although some satellite networks do offer the former. PTT is indispensable in a real-time group coordination scenario, but can’t support in depth conversations or (usually) long distances. You want both. It’s also basically impossible to receive a call on a handheld sat phone unless you schedule a time to be pointing the antenna at the sky.