
Ask HN: Is there something like a round trip “ping” for telephone? - chrisbennet
Problem: The majority of the robo&#x2F;spam calls I receive have a fake caller ID [1] so I can&#x27;t block them based on originating location.<p>Question: Is there something analogous to internet network &quot;ping&quot; (but the the phone network) that could be used to determine approximately how far away the caller truly is? The idea would be to flag calls [2] that can&#x27;t possibly be local yet have a &quot;local&quot; caller ID. Obviously, calls from cell phones can come from anywhere.<p>[1] Usually with the same 3 digits as mine i.e. (AAA) BBB-CCCC where AAA is area code, BBB is first 3 digits so they appear to be originating locally.<p>[2] Flagging might result in sending the call to voice mail or asking a question to test for human caller.
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bradknowles
Why not just use a whitelist and send all unknown callers to voicemail?

I swear that one of these days I will get around to creating such a system
based on twilio. I swear.

