What is a withheld number?
When a number is withheld, there is no caller ID, which means the recipient cannot see who is calling. A number can be withheld during digital, analogue or voice-over-IP (VoIP) telephone calls. The process of withholding a number is also called Calling Line Identification Restriction (CLIR). The recipient of a withheld number call usually sees a message such as “unknown” or “withheld number” in their phone display instead of a phone number.


Further information

Voice over IP

What is Voice over IP (VoIP)?
Voice over IP (VoIP) is the most common method for making phone calls over the internet. This is in contrast to traditional telephony, where communication is over the…

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