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Old 2nd Mar 2023, 3:17 pm   #1
Roger Ramjet
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Default Cold War Direct Lines

I was watching the early episode "Edge Of Darkness"' last night on BBC 4. In the closing scenes, DI Craven - having been irradiated by Plutonium is then being gassed by a task force in what seemed to be a similar room to the Cabinet War Rooms, containing loads of bakelite phones of differing colour's.

In desperation, Craven tries each phone in turn to call for help, but all were dead except for one which when the handset was lifted emitted a very authentic click plus old fashioned ring tone [despite no number being dialled]. The scene then changed to the basement of a building where a lady was perplexed to hear a phone ringing from an old empty office. She lifted a dusty old phone on the desk but it was not that one so she followed the ringing to a 232 Bakelite hidden beneath a pile of papers, picked up the handset then announced No 10 !

Despite dramatic license, I have no doubt that these type of direct lines existed & in fact I came across modern day ones in the 70's & 80's i.e. one was from a burglar alarm company direct to the County Police HQ and another was from the gatehouse of a ordinance factory [long since gone], once again direct to the County Police HQ.

Not an expert but I assume these would have been copper point to point circuits routed via at least one exchange which proved the ringing control & voltage. This then begs the question that will Direct Lines still be feasible when fibre replaces the copper ?

Roge

Last edited by Roger Ramjet; 2nd Mar 2023 at 3:18 pm. Reason: typo
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Old 2nd Mar 2023, 4:48 pm   #2
G6Tanuki
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Default Re: Cold War Direct Lines

There were all sorts of 'leased lines' available from the GPO/BT in times-past.

The BT SIN database still exists - https://www.openreach.co.uk/cpportal...n-notes-(sins)

Alas it no longer contains details of the legacy EPS8/EPS25 type circuits though.

Used for voice, data, and teleprinter services. Some similar were used for radio-studio-to-transmitter-site links.

These leased-lines were largely replaced by the likes of ISDN at the end of the last century; there's also the consideration that fibre is nowhere near as susceptible to nuclear EMP as copper-wires.

The old ROC posts with their landline-connected-and-phantom-powered "WB" units, and the RSG bunkers have all now been sold-off.


See http://www.ringbell.co.uk/ukwmo/Page213.htm

Somewhere I have one of the early-1980s ex-ROC-post Burndept VHF radios that were intended to be used in the event a nuclear war had destroyed the wired infrastructure. It probably still has the ROC-post crystals in it!

Also, there was "MOULD" for civil-defence stuff, which used a mix of low/high-band VHF, and UHF. The UHF MOULD repeaters were perplexingly interleaved with 70cm amateur-band repeaters!

See http://www.ringbell.co.uk/ukwmo/Page251.htm
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Old 2nd Mar 2023, 6:33 pm   #3
lesmw0sec
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Default Re: Cold War Direct Lines

In the days just prior to STD we used to dial various random numbers in the hope of identifying a tie line. I was taken aback on one such exercise when a very alarmed gentleman answered saying "Who are you - how did you get this number?" I did not ask who he was...
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Old 2nd Mar 2023, 6:43 pm   #4
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Default Re: Cold War Direct Lines

Relevant: https://bt.co.uk/pricing/notifs/01-0...0377_d0e14.htm
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Old 2nd Mar 2023, 8:44 pm   #5
Chris R
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Default Re: Cold War Direct Lines

Before the end of the Cold War, Regional Seats of Government and other vital places were linked by Private Wires ("PW's"), which were provided by the GPO. Although these would pass through exchanges, they were not accessible from outside. In addition to these were radio links which would pass through a number of hilltop sites, duplicating many of the PW's. These could be High Band VHF or UHF links. The VHF ones operated in a 1+1 mode (2 channels on one carrier) and the UHF ones could be 1+4 (4 channels on one carrier.
In addition to speech, many of the circuits carried data in the form of telex. There were GPO "S+DX" (Speech + Data) units which inserted the telex tones into a slot in the speech band. Filtering was employed, so that neither interfered with the other and the missing part of the speech band was not noticeable in practice. They were valve operated and worked very reliably.

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Old 2nd Mar 2023, 10:14 pm   #6
Graham G3ZVT
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Default Re: Cold War Direct Lines

In modern PABX parlance an extension that is programmed to ring a pre determined extension or PSTN number without dialling is called a "Hotline"

Nothing to do with the famous Washington to Moscow circuit of that name, which I believe was a Telex link.
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Old 2nd Mar 2023, 11:42 pm   #7
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Default Re: Cold War Direct Lines

I don't think point-to-point links were much used in government. Both the government and military have their own private switched systems. There would have been no need for a direct private link between 'Northmoor' and Whitehall.

EoD does capture the 1980s paranoia about the nuclear industry and government shenanigans very well though. There were all sorts of rumours and conspiracy theories circulating at the time.
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Old 3rd Mar 2023, 2:39 am   #8
Hartley118
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Default Re: Cold War Direct Lines

In the 1960s-70s, I was working with ICI (remember the name?) installing teleconference systems between their various sites. The sites were directly linked by decent speech-quality point to point 4-wire private Post Office telecoms circuits with separate send and receive pairs. It all worked pretty well, though as installer, one was literally just faced with 4 wires and left to work out the send pair and the receive pair. Considering both ends of the 4-wire circuit, there seemed many more ways of getting it wrong than right!

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Old 3rd Mar 2023, 2:41 pm   #9
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Default Re: Cold War Direct Lines

Quote:
Originally Posted by Hartley118 View Post
Considering both ends of the 4-wire circuit, there seemed many more ways of getting it wrong than right!
Mathematically provable

Four-factorial = 24 ways of connecting them, only one right. If phasing isn't important then 4 would work.

It's nice when you can objectively prove that they really are out to get you.

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Old 3rd Mar 2023, 7:07 pm   #10
Pellseinydd
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Default Re: Cold War Direct Lines

Quote:
Originally Posted by paulsherwin View Post
I don't think point-to-point links were much used in government. Both the government and military have their own private switched systems. There would have been no need for a direct private link between 'Northmoor' and Whitehall.

EoD does capture the 1980s paranoia about the nuclear industry and government shenanigans very well though. There were all sorts of rumours and conspiracy theories circulating at the time.
During the 1960's, I looked after a major hub of the Government's Defence Telecoms Network deep underground in Chester beneath the the Army's HQ Western Command - next level down from the War Office.

Started out there as a nineteen year old GPO Technical Officer - such a responsibility! Was also a Royal Signals TA second lieuntent. We had 24 direct circuits direct to Whitehall in addition to other major HQs throughout the UK all connected to a 20 position sleeve control manual board - the entire network was manual - didn't start going auto until into the mid 1970's.

Then in the mid 1990's a recovered a couple of manual sleeve control switchboards from the EMSS (Emergency Manual Switching System) which had been put in c1959/60 - again all manual until it became redundant with the end of the Cold War c1992. I rebuilt it for the BBC's 'Hello Girls' TV series in 1996 and 1988 - most episodes areon You Tubebut make sure you put 'BBC' in as well as 'Hello Girls or you get some interestng results !

BT also had its own 'manual switching sysyem for wartime use until early 1990's. Both the EMSS and BTEMS were not well known for security reasons - documents were classified - some up to 'secret' level. Sorry can't let you have copies!
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Old 3rd Mar 2023, 7:34 pm   #11
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Default Re: Cold War Direct Lines

The 'military' fallback, as well as forward-lines [think: how do you provide voice/teletype/fax comms to forces in Germany after most of the infrastructure has been nuked] was the 1960s BRUIN and followon 70s/80s Ptarmigan [designed/built by Plessey].

VHF/UHF multiplexed, with encryption if necessary. Patching and potentially interworking with surviving wired infrastructure. I did an exercise with the TA where we spent a week under supposded NBC-attack scenarios, meaning the only time you could take off your NBC-suit was after decontamination, and an airlock into a 'clean' space.

Trust me, after three days in a NBC suit you were basically marinaded in your own body-fluids.

There was also the US AUTOVON; we interworked with this too. Their phones were DTMF but as well as the usual buttons they had four red 'Precedence' extras with names like "Flash Special" and "Flash Override". These would let you 'force' a call through the network if it was congested, by dropping lower-priority calls that were causing the congestion.

https://en.wikipedia.org/wiki/Autovon
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Old 3rd Mar 2023, 7:37 pm   #12
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Default Re: Cold War Direct Lines

The big government bunker underneath Corsham had a substantial manual exchange: https://en.wikipedia.org/wiki/Centra...r_Headquarters
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