[fuckstick]

No I am fully aware. We used to process credit cards over the AMPS (analog) mobile phone network - and this is also how EKGs were sent by EMTs in that timeframe - prior to that in the 1970s they used a dedicated chunk of 70cm spectrum. The items listed are a seriously small amount of data. Sure it’s a bit cheaper now - but we were integrating GPRS modules into embedded hardware in the 90s, it wasn’t that expensive.

[Teever]

What was the coverage map of something like AMPS? Was it ubiquitously available like GSM more or less is now?

[fuckstick]

It was ubiquitous enough in urban and suburban areas in the US and Canada. The coverage of AMPS was solid, what was limited was the bandwidth and capacity - but there were far fewer users. Coverage in remote rural areas was poorer but still - in the late 80s it was being used for EMT transmittal of telemetry. And as stated using dedicated spectrum this is a 1970s tech. On rereading the OP I am more puzzled what they are talking about because it seems like they are talking about EMT monitoring as opposed to continuous home monitoring - the former we have been doing for 50 years.