Silly old Britain relying on a largely subterranean circuit switched network whilst the cool kids might use the latest cool gear to get an important message through. Even today, whilst Facebook danced the grim fandango for an eye watering six hours, boring old standard issue comms carried on functioning.

It sounds a bit daft but there was a massive network of red boxes all over the country with decent connectivity back to a network of exchanges etc etc POTS n that. The AA (Automobile Association) had their own boxes too. To use this network you needed a few pence. To get the message through you use keywords and passwords ie a protocol. The failure modes for a satellite phone in those days doesn't bear thinking of.

When the message is important, keep it as simple as possible but no more.