[VoiceOps] Preventing calls to cell phones with guaranteed accuracy

[John Levine]

>> most landline carriers won't port it to a landline if it's out of
>> ratecenter.
>
>I thought ports were only possible within a rate centre, and so by 
>definition impossible to port to a carrier which doesn't operate in that 
>rate centre?

It is my impression that ports are technically possible anywhere
within a LATA, but for business reasons most telcos won't port between
rate centers.

They're definitely not possible across the country because long
distance calls only do the LNP lookup after routing the call to
the destination tandem.  (That's the "L" in LNP.)