Most of the arguments I end up having about caller ID turn out to be arguments about words. One person says "spoofing" and means a criminal. Another says it and means a business that borrowed a nearby number. Both are describing a call that shows your town on the screen while the caller sits somewhere else, and both are partly right. So here is the vocabulary, in plain terms and in the order that makes sense when your phone is ringing. The terms are grouped by where you meet them: on the screen, in the caller's toolbox, and in the rules and filters that push back.
On your screen
- Caller ID
- The number (and sometimes a name) shown when a call arrives. It is whatever the calling system put in a field called the calling number, and your phone displays it faithfully. Your phone made no mistake. It cannot check the claim.
- Area code
- The first three digits of a ten-digit number, a label for the region where the number was first assigned. It does not tell you where a phone is today. For what it can and cannot show, see the guide to tracing a number.
- Exchange
- The three digits after the area code. A caller who matches your area code and your exchange looks like a neighbor on purpose, because the first six digits of the number feel familiar.
- Overlay
- A second or third area code laid over the same map after the first ran short of numbers. In an overlay region, calls from two or three different codes can all be truly local.
- No Caller ID
- The number was hidden or not passed along. A caller can choose this, for example by dialing *67 before a call, which hides the number for that one call.
- Unknown Caller
- Your phone did not receive a number, or could not identify one. It sounds like the entry above and means something slightly different, which is why I keep the two apart.
- Spam label
- A tag such as "Scam Likely" (T-Mobile), "Spam Risk" (Verizon Call Filter) or "Potential Spam" (Google's Phone app). The carrier or app attaches it from its own signals. It is an estimate and sometimes wrong in both directions.
What callers do
- Spoofing
- Putting a number in the caller ID field that is not the real origin of the call. By itself the word covers both harmless and harmful cases, and the law cares about intent, as the entry on the Truth in Caller ID Act explains.
- Local presence dialing
- A business displays a number from the area it is calling, usually one it holds or is entitled to use, because people tend to answer local-looking calls. It is a sales technique and can be unwelcome, but it is not the same as fraud.
- Neighbor spoofing
- A caller picks a number that shares your area code and often your exchange, hoping you will take the call. The display looks identical to local presence dialing. The difference is who is behind it and whether the number is theirs to use.
- Own-number call
- A call that shows your own number as the caller. Any caller can place any number in the field, including yours. It does not mean your phone was hacked or that anyone is inside your account. Do not answer questions, press keys or call back.
- Dialer
- Software that places many calls from a pool of numbers and hands you to a person or a recording. A short pause after you say hello often means a dialer is waiting to connect you. Calls from numbers sharing the same first six digits are a common footprint, which the call history walkthrough teaches you to spot.
- One-ring call
- A call that rings once and stops, hoping you will call back. Also called wangiri, from the Japanese for "one ring and cut". Some use Caribbean or Canadian codes that dial like domestic ones, so the return call can be billed at international rates. More in the essay on country-code prefixes.
- VoIP
- Voice over internet protocol: the voice travels as data. VoIP numbers are used by households and businesses, and the technology is not a sign of bad intent. See the VoIP cheat sheet.
Rules and filters
- STIR/SHAKEN
- A standard for signing caller ID so one carrier can vouch for how a call entered the network. Carriers are required to use it under the TRACED Act of 2019. It helps, but it does not promise that a call is wanted or honest.
- Truth in Caller ID Act
- The US law that prohibits showing misleading caller ID with the intent to cheat or cause harm. It does not outlaw every changed display, which is why a business showing a number it is entitled to use is a different matter. This is general information, not legal advice.
- Do Not Call Registry
- A national list, running since 2003, that you join at donotcall.gov or on 1-888-382-1222. It curbs legitimate telemarketers. It does not stop scammers, political calls, charities or surveys.
- Silence Unknown Callers
- An iPhone setting, at Settings > Phone > Silence Unknown Callers, that sends calls from numbers outside your contacts to voicemail. Check your voicemail now and then, because real calls can land there. On Google's Phone app the matching tools are under Phone > the three dots > Settings > Caller ID & spam.
- Callback check
- My own name for the habit that settles most cases: do not call the number that rang. Look up the organization's number on its website, a statement or the back of your card, and ask whether anyone tried to reach you. It avoids rewarding a spoofed call and avoids connecting you to an innocent person whose number was borrowed.
- Report
- Scam calls go to ReportFraud.ftc.gov, and spam texts are forwarded to 7726 (SPAM), which passes them to your carrier. The FCC takes complaints about unwanted calls through its consumer pages.
If a term here is new, the most useful next step is the practical one: what a call from your own area code means, or the number reader, which shows you the region and time zone behind a code without pretending to know who is calling.