As an aside, much of the electronicv work for codebreaking in the UK
> in WW2, including Colossus, was done, IIRC, by
people from the GPO
> research labs. GPO = General Post Office, who at the time ran the
> telephone system in the UK, and who therefore had great expereience of
> switching systems.
The Enigma key recovery was done using the multi enigma simulators (bombes)
designed by Alan Turing and built by the British Tabulating Machine Company.
The GPO had a research station at Dollis Hill in north London.
One of their engineers was a certain Tommy Flowers who had done research
into valves as switches as opposed to your bog standard 3000 series PO
relay.
He found that provided you left the valves switched on they were nearly as
reliable as relays and of course much faster.
Flowers knew the Bletchley Park people as the Bombes were all relay and
motor driven and Flowers was the PO research man on fast switching.
Colossus was designed to attack something other than Enigma. To be exact the
Fish series of teleprinter cipher attachments. Whilst they could read the
tapes optically at high speed they could not react fast enough to matches.
They consulted Flowers informally and at least at first, he helped
(unfunded) to design and build the logic side out of valves.
Regards
?
Rod Smallwood
-----Original Message-----
From: cctech-bounces at
classiccmp.org [mailto:cctech-bounces at
classiccmp.org]
On Behalf Of Tony Duell
Sent: 16 September 2012 18:00
To: cctalk at
classiccmp.org
Subject: Re: Microsoft cordless phone
>
> On 15 Sep 2012 at 20:01, Tony Duell wrote:
>
> > As an aside, much of the electronicv work for codebreaking in the UK
> in WW2, including Colossus, was done, IIRC, by
people from the GPO
> research labs. GPO = General Post Office, who at the time ran the
> telephone system in the UK, and who therefore had great expereience of
> switching systems.
>
> Maybe, but in the 70s when I visited, telephones in Britain were a
> nightmare compared to their US counterparts--particularly pay
In the 1979s. the UK telephoens were still essentially a government
monopoly. Everything had to be rentyed from the GPO, you couldn't do any
mdoifications yourself [1]. Pkug-in telephones were very rare, most werre
hardwired. If you are interested in finding out more about the wiring of
subscriber equipment in the UK -- telephone schemantic,s how extensions
were wired [2], etc, then do a goodle search for N diagram. And enjoy...
[1] That's not to say it didn't occur :-)
[2] Multiple phones opn a line were a bit odd. The speech circuitry was
wired in paralel, the ringers (bells) in series. Evey extension scheme
had a 'Plan' number -- Plan 4 is the one for plug-in telephones. Note
that there are different versiosn of Plan 4 depending on whethr you
rented one telephoen or morte than one. I guess if you decided ot rent a
second telephoen on Paln 4, an engineer had ot come out and rewire all
the sockets and the existing telephone. You were saying... :-)
On the other hand, the Planphones (telephoens with swithcing to
extensions, facilities to call exten sions, etc) are rather fun.
telephones. And doesn't England still have
coin-op residential
electrical service? When I heard this referred to on an old
Yes and no. It is not common, virtually everyone has a normal watt-hour
meter that is read 4 times a year (or should be) and gets a bill shortly
after.
However, if the electricity company thinks you're a 'bad risk' and are
likely to not pay the bill, they can install a prepaymetn meter. In the
old days, that was something you put coilns in (often shillings, not
pennies), nowadays it more likely you put money on a smartcard or similar
at a local shop and use that to add credit ot the meter. That way the
meter iteslf never contains coins, and they don't have to send soembody
round to empty it (such people were attecked for the money they carried,
and often scuh meters were used in less 'desirable' areas...)
I can see why a scrap dealer would be likely to be judged a 'bad risk'...
-tony