Chris Green  wrote:
> OP here - I'm in the UK but the system this is for will be in France.
> So digging out specialist providers and such is one level more
> difficult than doing it 'at home'.

Just a thought, but have you considered using SMS to ask the remote end to
initiate the connection?

You send a text saying 'wake up now', the boat receives it, 'dials' a 3G/LTE
connection and connects to your VPN (or SSH tunnel).  Now you can access it.
After a while of inactivity it drops the connection and goes back to sleep.

If the duty cycle is low (eg you connect for 5 minutes a week) it could work
out cheaper than having an always-on VPN connection that's consuming traffic
in keepalives.

That also means you can use any SIM you like, so pick whatever tariff suits
you.

Typically, dongles provide multiple USB-UART channels - one for the PPP data
connection, another for signal stats and SMS, maybe a third for something
else (GPS?).  I don't know the best framework for handling the SMS side, but
at the least something polling it with AT commands would do.

Theo

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