# The Difference Between an Unknown and a Withheld Number

Discussion in 'Computer Science & Culture' started by Cellar_Door, Jan 30, 2011.

1. ### Cellar_DoorWhose Worth's unknownRegistered Senior Member

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At 3am last night I got woken up by a load of phone calls from a number my phone called 'Unknown'. I would have normally picked up but I was too tired to bother, and in the morning I saw that I had 10 missed calls altogether.

I've read before that 'unknown' as opposed to 'withheld' numbers are usually from dodgy companies and cold-callers. However, somehow I find it hard to believe that a company would ring me at such a strange time of day. What's more, the calls were irregular in the length of time they allowed the phone to ring and even in the pauses between calls.
Therefore, I'm more inclined to think that the calls (seeing as it was a Saturday night after all) were from one of my drunk friends wondering why I wasn't out - or even just prank calling me.

Is this probable or even possible?

My phone is a Sony Ericsson w995, and putting '141' in front of my number before dialling it always comes up as 'withheld'.

3. ### PinwheelBannedBanned

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Withheld is when the caller withheld their number.
Unavailable/unknown is when the phone company does not have the caller's number.

5. ### Cellar_DoorWhose Worth's unknownRegistered Senior Member

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What does that actually mean though?

7. ### PinwheelBannedBanned

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That the phone company doesnt have the phone number on record.

8. ### Cellar_DoorWhose Worth's unknownRegistered Senior Member

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I mean, what would that suggest? That the number is from abroad? From a company? Is this always the case?

9. ### PinwheelBannedBanned

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It means that they dont have it on thier records. Whether abroad or domestic, it doesnt matter its just not on thier database.

10. ### cosmictravelerBe kind to yourself always.Valued Senior Member

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Perhaps someone using a disposable cell phone?

When in search of a Disposable Cell Phone they will be available online or at convenience stores near you. Taking advantage of their low cost (under $15 for the phone and basic service plan)and possible rebates for recycling ($5 value for most models)these Disposable Cell Phones are really useful.

11. ### domesticated omInterplanetary homesteaderValued Senior Member

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SciForums fail......7 posts, and not one linear equation joke

12. ### PinwheelBannedBanned

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Well theres a difference between an known unknown and an unknown unknown.

13. ### Gremmie"Happiness is a warm gun"Valued Senior Member

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But the difference is unknown.

14. ### PinwheelBannedBanned

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Yeah, I know.

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Not exactly. (I'm an old phone company guy.) It really means that the phone company cannot determine the number. The office which received the call and then sent it on to the office serving your phone did not forward the caller-ID. If the number was blocked from the phone, it would have forwarded that information (as you already know).

But since you received *nothing* at all, that meant nothing was sent from the originating office. There are three things that can case that: An equipment malfunction in the office; a database crash or update in progress; the caller is using a spoofed connection to place the call.

16. ### Ahemembrace simplicityRegistered Senior Member

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The call was probably generated from a rotary number. I work in an office with one listed number, but there are 30 lines. When someone in the office calls a phone with caller ID, their display says, Unknown. Our lines have to be blocked so the internal rotary numbers don't ring.

17. ### Fraggle RockerStaff Member

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If you make a call using a calling card it will also display as "unknown."