Herbert Graf wrote:
> On Thu, 2007-10-04 at 20:06 +0100, peter green wrote:
>> On the other hand it strongly discourages marketing calls and other 
>> timewasting calls to mobiles (yes I know the US has a law against 
>> marketing calls to mobiles but from what I can gather it is widely 
>> ignored, also in the US you can't even tell from the number if you are 
>> calling a mobile).
> 
> 
> Actually you can tell (to a point), if you have the right contacts.
> 
> The prefixes for cell phones are always different from landlines since
> cell phone providers buy up prefixes in blocks. The general person can't
> tell, but phone providers certainly can.

Not true in the U.S. anymore -- we have local number portability and any 
number can literally go to any end-device.

With the advent of nationwide long-distance plans available on just 
about any type of phone (cell, VoIP-based, or POTS) for very cheap, this 
also means that many people are even keeping their old area codes when 
they move.

(When a couple people in my family moved back to Colorado from Texas, 
they had their Texas numbers on their cell phones for a couple of years 
until they changed/re-upped their cell contracts.)

The only way to know for sure "where" a phone is, is to work for a 
carrier and trace the call via call routing logs, anymore.

Nate
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