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You can send and receive SMS using Wifi only (VoWIFI) which most carriers support even the cheapest MVNOs. It's usually referred to as "WiFi Calling" Again, yo

You can send and receive SMS using Wifi only (VoWIFI) which most carriers support even the cheapest MVNOs. It's usually referred to as "WiFi Calling" Again, you DO NOT need a cell phone tower to send and receive SMS and phone calls. You can register your phone on its home network near a tower and go WiFi-only forever after.

nixgeek 4y ago
OP appears to have attempted it. “ One issue is that the protocol for wifi calling is notoriously opaque. Carriers frequently change the underlying infrastructure and protocol details. Also, the protocol assumes terrestrial broadband with reasonable latency and bandwidth. At McMurdo, as of this writing, latency to terrestrial locations is in excess of 700 milliseconds. Usable bandwidth for any given end user can vary widely, down to a few dozen kilobits per second. The protocol also doesn’t expose any useful diagnostic info to the end user in order to troubleshoot. You just have to cross your fingers that the magic “wifi calling” icon lights up.”
rsync 4y ago
"You can register your phone on its home network near a tower and go WiFi-only forever after." This is how it works on paper. You may have had success with this. It does not work universally. It won't take long to find a bank / FAANG / service provider that refuses to accept anything but a bona fide mobile SIM talking to a base station.
- ridgered4 4y ago
  > It does not work universally. It won't take long to find a bank / FAANG / service provider that refuses to accept anything but a bona fide mobile SIM talking to a base station. How does a SMS sender know this? Is there some mechanism in SMS to only deliver if by certain criteria?
  - copenseethe 4y ago
    - orangepurple 4y ago
      You can use a handset with its SIM card on WiFi without a tower ever again if you provision the SIM card on its home network once. Nobody is suggesting using anything but a handset.
      - copenseethe 4y ago
    - rsync 4y ago
      "Yes. There is a database they query to see if it’s tied to a handset, or just a virtual number." Or they do an API lookup and query the type in realtime. Elsewhere in this thread I posted the syntax for performing this lookup using the twilio API ...

nixgeek 4y ago

OP appears to have attempted it. “ One issue is that the protocol for wifi calling is notoriously opaque. Carriers frequently change the underlying infrastructure and protocol details. Also, the protocol assumes terrestrial broadband with reasonable latency and bandwidth. At McMurdo, as of this writing, latency to terrestrial locations is in excess of 700 milliseconds. Usable bandwidth for any given end user can vary widely, down to a few dozen kilobits per second. The protocol also doesn’t expose any useful diagnostic info to the end user in order to troubleshoot. You just have to cross your fingers that the magic “wifi calling” icon lights up.”

rsync 4y ago

"You can register your phone on its home network near a tower and go WiFi-only forever after." This is how it works on paper. You may have had success with this. It does not work universally. It won't take long to find a bank / FAANG / service provider that refuses to accept anything but a bona fide mobile SIM talking to a base station.

ridgered4 4y ago
> It does not work universally. It won't take long to find a bank / FAANG / service provider that refuses to accept anything but a bona fide mobile SIM talking to a base station. How does a SMS sender know this? Is there some mechanism in SMS to only deliver if by certain criteria?
- copenseethe 4y ago
  - orangepurple 4y ago
    You can use a handset with its SIM card on WiFi without a tower ever again if you provision the SIM card on its home network once. Nobody is suggesting using anything but a handset.
    - copenseethe 4y ago
  - rsync 4y ago
    "Yes. There is a database they query to see if it’s tied to a handset, or just a virtual number." Or they do an API lookup and query the type in realtime. Elsewhere in this thread I posted the syntax for performing this lookup using the twilio API ...