[woodruffw]

Tangentially related: it's fascinating how much of the cellular messaging network runs on (or at least speaks) SMTP and IMAP. These SMS/MMS gateways are just one example; Visual Voicemail[1] also runs on IMAP and it also shows up in mobile terminal (i.e., phone) testing standards[2].

[1]: https://www.gsma.com/newsroom/wp-content/uploads/2012/03/omt...

[2]: http://www.omtp.org/OMTP_Terminal_Testing_1.0.pdf

[pilsetnieks]

This is just an outside interface, the actual networks don't run on SMTP and IMAP in any way, rather, it's things like SS7 (https://en.wikipedia.org/wiki/Signalling_System_No._7) and SMPP (https://en.wikipedia.org/wiki/Short_Message_Peer-to-Peer)