Globalstar had some really rough system issues about 10 years ago when their constellation was dying. They were so desperate for Duplex users they had plans as

Globalstar had some really rough system issues about 10 years ago when their constellation was dying. They were so desperate for Duplex users they had plans as cheap as $50/month unlimited everything - voice, SMS, and 9600 baud dialin data. At this point it's very much a "we want to stop selling satellite voice services and just let IoT have the whole lot".