Samuel Chiltern answered
The difference between withheld numbers and unknown numbers
When you receive a call from a withheld number, this means that the caller doesn't want his or her number to be displayed on the screen of the handset being called.
An unknown number means that the caller ID is literally not known by the telephone system.
When you receive a call from a withheld number, this means that the caller doesn't want his or her number to be displayed on the screen of the handset being called.
An unknown number means that the caller ID is literally not known by the telephone system.
Withheld numbers
In the case of withheld numbers, the telephone system (i.e. Your network provider) knows the caller ID, but the caller chose to hide his or her number, usually for privacy reasons.
Unknown Numbers
An unknown number is literally not known by your network provider, which could mean that the call originated from overseas, or that the caller might have used a phone card to make the call.
It might also be the case that the caller is domestic, but that your network provider doesn't have the details for this number on their database.
This is presumably due the time it takes for network operators to keep their databases up to date with new numbers, which are being registered at an increasingly rapid rate as mobile phone ownership continues to grow.
Call Screening
A reputable and well-established organisation is likely to use recognised numbers and is also unlikely to withhold their number.
As a rule of thumb, I tend to ignore calls from "unknown" and even "withheld" numbers since, in my experience, they usually turn out to be cold-calls or scamming attempts.
In the case of withheld numbers, the telephone system (i.e. Your network provider) knows the caller ID, but the caller chose to hide his or her number, usually for privacy reasons.
Unknown Numbers
An unknown number is literally not known by your network provider, which could mean that the call originated from overseas, or that the caller might have used a phone card to make the call.
It might also be the case that the caller is domestic, but that your network provider doesn't have the details for this number on their database.
This is presumably due the time it takes for network operators to keep their databases up to date with new numbers, which are being registered at an increasingly rapid rate as mobile phone ownership continues to grow.
Call Screening
A reputable and well-established organisation is likely to use recognised numbers and is also unlikely to withhold their number.
As a rule of thumb, I tend to ignore calls from "unknown" and even "withheld" numbers since, in my experience, they usually turn out to be cold-calls or scamming attempts.