# How does the \*67 blocking your Caller ID thing work on a phone? **URL:** \ **Category:** Factual Questions\ **Created:** [January 6, 2022, 8:56pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343 "2022-01-06T20:56:08Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [January 6, 2022, 8:56pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/1 "2022-01-06T20:56:08Z")
So, apparently dialing \*67 at the beginning of a phone call has the effect of making that call anonymous, hiding your Caller ID. But how exactly does that work, and is it some sketchy third-party service that is doing the hiding for you? ---
**Author:** ![doreen](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@doreen](https://boards.straightdope.com/u/doreen)\ **Post date:** [January 6, 2022, 9:02pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/2 "2022-01-06T21:02:53Z")
It’s the phone company that does the blocking. \*67 is for per call blocking but you can arrange for a complete block on the line and then must dial \*82 ( I think) to unblock a particular call ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [January 6, 2022, 9:07pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/3 "2022-01-06T21:07:02Z")
According to this site it may not work for all phones, but there are other ways for phones that are exempt: > **[\*67 Meaning and How it Works](https://www.globalcallforwarding.com/tips/star-67-meaning-and-how-it-works/)** > > Wondering how \*67 can work to show you calling from an unknown number? Find out more about this simple, free, and easy-to-use caller ID tool. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [January 7, 2022, 1:06pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/4 "2022-01-07T13:06:41Z")
> [@doreen](#): > > dial \*82 ( I think) to unblock a particular call Yep. My phone is set up to block my caller ID for every call I make. My contact list is set up to dial \*82-xxx-xxx-xxxx for every contact’s number, since they know my number already. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [January 7, 2022, 1:42pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/5 "2022-01-07T13:42:44Z")
To add more detail, \*67 blocks CID but not Automatic Number Identification (ANI) which is passed between the exchanges and phone companies for billing and audit purposes. ANI is never passed to the callee. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [January 7, 2022, 9:13pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/6 "2022-01-07T21:13:48Z")
And even if you block your out-going caller ID, you still cannot block it when calling 911 and perhaps certain other magic numbers. ---
**Author:** ![doreen](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@doreen](https://boards.straightdope.com/u/doreen)\ **Post date:** [January 7, 2022, 9:30pm UTC](https://boards.straightdope.com/t/how-does-the-67-blocking-your-caller-id-thing-work-on-a-phone/957343/7 "2022-01-07T21:30:23Z")
I think it is passed to the operators of 800 and other toll-free lines as they are paying for the call and it should be on their bill.