The # that shows on cell phone is only 4 digits 6842
A 13-digit number is likely an international phone number, as most domestic numbers are shorter. To identify the caller, you can look up the country code in the number or use a reverse phone lookup service. If you're unsure about the caller's identity, it's best to be cautious before returning the call or providing any personal information.
I am not sure, if the number displayed is a valid call ID number, but Caller ID displays the phone number of the person who made the call to you including the area code and phone number. From this you an identify the person calling you. If you have a phone book system in the phone and you have saved phone numbers with names, some phones will display name of the person from the address book when the caller id matches the stored number. Some times the number displayed on caller ID is not a standard phone number. Some of these calls may be from a VOIP service or from some customer service call centers (internal on the service provider network) or when the caller ID is masked by the caller or caller's network service provider. - Neeraj Sharma
Star 67 is a feature on some phone systems that allows the caller to block the display of their phone number when making a call. By dialing *67 before dialing the recipient's phone number, the recipient will see "Private Number" or "Unknown Caller" on their caller ID.
Today, about 99% of phones come with a caller ID service that is automatically enabled by default. When it comes to home telephones (landline) with caller ID, one could contact their phone company and opt out of the caller ID service if needed. More importantly, the caller ID feature that we have come to trust is not as secure as it was in the past. Anybody can change or fake the number that is displayed on the caller ID with a simple spoof calling card. Be careful and remember that anyone can change their caller ID number.
It defines whether your phone number will be displayed on someone's caller ID unit when you call them. Select 'no' if you wish your number to remain private.
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It is possible to "spoof" caller id. If you operate your own PBX or you use one of the IP (internet) phone services with lax security, you can change the number that shows up on caller id to be anything you want it to be.
For your name to be displayed on the caller id, the person you are calling should have your name stored in their phone, along with your phone no. So, when you call, the system recognises your phone number, and then displays or announces your name.
You are correct that there is no area code 421 in North America (USA, Canada, etc.). The two most obvious possibilities:You received a call from Slovakia in eastern Europe, country code +421, orSomeone "spoofed" a fake Caller ID number.Unfortunately, it is very easy for anyone with a PBX (business phone system) to send any number they please in place of legitimate Caller ID data.
Basically you can't - the whole point of a caller being able to with-hold their number - is to prevent it being stored by the called party's equipment.
"star" 67 then the phone number you are dialing
Caller ID