I am wondering what the standard tool is for sending and receiving SMS and MMS on a device that does not have a SIM card in it.
Is there some tool that can do it natively? Is there a specific carrier that is commonly used for this? Is there some sort of selfhosted service that bridges it to email, and if so do I need to put a SIM card in my server?
Bonus points if I can do it within Emacs.
Well you’d start here
https://www.geeky-gadgets.com/how-use-meshtastic/
You self host a comms server, i use matrix, and that forwards the message to you.
If you’re directly tied to the SMS protocol you can setup a repeater here https://hackaday.com/2022/02/21/an-off-grid-makeshift-cell-network/
https://wiki.matrixcomsec.com/index.php?title=How_to_send_and_receive_SMS_using_SMS_Gateway_in_SARVAM_UCS%3F
Then it’s meshtastic -> Matrix -> SMS gateway