Does *67 really block caller ID?

[budmaster]

*67 - Block Caller ID (For Next Call Only)

I tried *67 today. No answer. But the recipent immediately returned my call. The recipient did not see my name, but was able to return the call. I did look at the call history on my phone just to double check *67 was dialed. *67 did not show on the VOIPO call history. I tried to replicate making a *67 call to my own cell; but I could not replicate. Is it possible that *67 does not always work?

[holmes4]

The recipient could have used *69 to return the last call without caller ID. The phone company knows your number.

[VOIPoTim]

When you block CID, the number is still technically sent in the call headers, but it's flagged as "private". Occasionally there will be a receiving provider that refuses to honor the privacy flag and shows it.