"Stephen Osborn" wrote in message
...
"Martin Underwood" wrote in message
...
"John Shelley" wrote in message
news
Martin Underwood wrote:

The association of a single code with a geographic area disappeared
decades
ago. Harrow has the 8424, 8427, 8861 and 8863 codes. In the predigital
days I believe these were normally co-located in the same exchange
building.

Well it exists to the extent that there is one or more codes that relate to
a specific geographical area (eg a town or a collection of neighbouring
towns/villages) but don't relate to anywhere else: given a phone code, you
can say which places use it[*]. Maybe the boundaries have become a bit more
blurred and the regions have got larger (like a two-letter code in a car
registration number used to relate to a specific town, whereas now it
relates to a group of counties).


Nowadays the exchange equipment is orders of magnitudes smaller, so in
some
case your 'local' exchange is actually located in an exchange building in
a
neighbouring area, along with half a dozen other 'local' exchanges.

Your 'phone line will physically be connected to a some sort of device
locally. However this could be a consolidation device that takes all of
those lines on to a neighbouring exchange building. Alternatively it
could
just take *some* of those lines to a neighbouring exchange building if
there
are logistcal reasons. For example the one room in the building still
being
used for exchanges only has room for three and a half sets of lines -
don't
forget that at some stage 9,999 lines have to be connected up to each
local
exchange.

To answer your specific question, I believe that anyone in Harrow will
get
one of the above codes *if one is available*. If not they will get one
form
one the exchange in the exchange building where their 'phone line ends up.

What about the situation where the same code is used by several towns and
villages, each of which has a telephone exchange. My code is used by two
moderate-sized towns and many neighbouring villages. I know that my village
has its own exchange (the building is about 100 yards from me right now!).
Presumably some form of supernetting is used: the first one or two digits of
the subscriber's number determine which exchange (consolidation device) the
call is routed to.

[*] I used to work with a guys who was a walking look-up table. He had each
memorised the STD codes and could tell you the code for anywhere or which
places a code relates to (we tested him and he was spot-on every time!). As
if this isn't "sad" enough, he couldn't see that this skill was perceived as
"sad" rather than endearing him to people. He could also see a photo of a
car dashboard instrument (eg a speedometer) and tell you every make/model of
car that it had ever been fitted to.