4 ms·

Because the design of the original caller-id system allows the initiator of the call to attach any set of numbers they like as the caller-id value that is shown

• phkahler 5y ago
  Which is hilarious because the phone company used to charge extra to bring you this information as if they were telling you who was calling. That's a service I'd almost be willing to pay for today if it actually worked.
  • pwg 5y ago
    Which is also why it is simply an "initiator settable field". When "the phone company" brought out the service (for a monthly fee) there was only one "phone company" and so they could be assured that they themselves were setting the value to the correct source. Now that the phone network looks more like the internet (many different companies all exchanging "calls" with each other) that decision, way back then, has the unintended side effect of allowing the robocall spammers to set whatever set of ten digits they like on their outgoing calls.