Caller ID Check

When you call someone, the phone network sends a number along with the call, and the phone you call shows it. That number is the caller ID, in telephone networks CLIP, Calling Line Identification Presentation.

It can be withheld, which is CLIR, and a business phone system may send another number the business holds, such as its main number, instead of the line's own. This check shows what actually arrives.

• Press Get a number. One of the test numbers is set aside for you for 5 minutes.
• Call it from the phone you want to check. On a phone, a tap on the number starts the call.
• The call is rejected as busy straight away, and the page shows the caller ID it arrived with, usually within a few seconds.
• Check again gets a new number, for a second try with the number withheld or from another phone.

• The call is rejected as busy straight away, so it is never answered and normally costs nothing. Should your provider charge for it all the same, it is billed as a call to a German landline; your provider can tell you the rate.
• The test numbers are German landline numbers. The check shows what arrives there; another network may in rare cases receive a number in a different form.
• A call to a test number never reaches a person, whether a number is reserved for it or not.
• 3 people can check at the same time. When every number is in use, the page says how long until one is free.