I told someone I'd check for a cellphoneless solution but it seems fully locked into the cell systems.
Short Message System is outside my experience but I've been reading up. The history doesn't help much and gateways into this system seem to be for businesses with big $$$ subscriptions.
I did find lots of (I think) obsolete dialup systems complete with AT command scripts for Linux!
Any el-cheapo SMS going on among the experts here? TIA