On Sun, 19 Jul 2009, Roland Perry wrote:

In message
, at
04:00:47 on Sun, 19 Jul 2009, John B remarked:
Are BT phone numbers even still /supposed/ to be geographical?

If they are traditional landlines, then each exchange has a specific
area it covers. But it's been possible for a generation to get "out of
area" numbers if you paid enough.

Haha, so there's no technical reason for having area codes any more,

There *is* an underlying technical issue, in that out-of-area codes don't
scale, because they involve running wires from one exchange to the other.

My understanding is that there are already wires running from one exchange
to the other. That's how the phone calls get around, d'you see.

Out-of-area numbers don't involve special wires. It's done with software,
in the routing layer. But it's not done terribly well, so there is still a
cost - cheaper than special wires, but more than zero.

Clive Feather gave a good explanation of this some time ago on this group.
From what i remember, everyone agrees that there's a sensible way to do
number porting that wouldn't require exchange Q to be involved in a call
from A to B just because B's number was once at Q, but that's not how
things work at the moment, and getting it changed is going to be a painful
process.

tom

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