[testis321]

Tetra is the "mobile phone" that our emergency services (well, police and firefighters atleast, not sure about ambulances) use. It offers "normal" calls and messages, ut it also offers push-to-talk, and group talks (needed for teamwork).

5G is set to replace tetra, with dedicated frequencies for emergency services, and those features implemented - so this will become the "mobile phone", using dedicated frequencies on current basestations, while the data in the backend will be transfered via 5G standards (with additional moficiations for PTT and group talk).

So yes, the technology behind is different, but the usecase will be the same.