BT line tester

Discussion in 'Electrics UK' started by opps, 20 Jul 2021.

  1. wgt52

    wgt52

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    Sorry, the Director exchanges went a long time ago certainly before 1995. Since then the whole of London has been on digital exchanges (Sys.X or AXE).
    The London Code is 020 (similarly, Coventry is 024 with 76 added as a prefix to the old 6 digit numbers, Northern Ireland code is 028) with '3nnn' a London wide routing, '7nnn' inner London and '8nnn' outer London.
     
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  3. wgt52

    wgt52

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    Sorry, the Director exchanges went a long time ago certainly before 1995. Since then the whole of London has been on digital exchanges (Sys.X or AXE).
    The London Code is 020 (similarly, Coventry is 024 with 76 added as a prefix to the old 6 digit numbers, Northern Ireland code is 028) with '3nnn' a London wide routing, '7nnn' inner London and '8nnn' outer London.
     
  4. Taylortwocities

    Taylortwocities

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    Yes strange that, as telex communication is a simple 5-bit unencrypted code. It relies on the simplest of handshake (answer back from the remote end) and yet it still has a high degree of trust. Maybe, now the high value transactions are now on the highly secure internet :rolleyes:
    there’s not much point in hacking the message about a few steel rods:mrgreen:
     
  5. JM2

    JM2

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    I must have lost the plot then - sometime after the 01 to 071/081 changes; because after that was 0171/0181 (leaving the 3+4 format intact); which went to 0207/0208 (and again 3+4).
    I've missed it going 020 (4+4) somewhere.
    - I've not been in that there London few a few decades (well, the odd visit). That's my excuse and I'm sticking to it :)
     
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  6. boringoldcodger

    boringoldcodger

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    It wasn't quite like that, for some time (many months, possibly more than a year) you could use either 0171 or 0207, equally 0181 or 0208 so within London we had to use 11 digit numbers. Then 0181 & 0171 were scrapped and 020 became the London prefix.
     
  7. SUNRAY

    SUNRAY

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    Indeed anything with a wayleave has a similar sort of legal status as rental or lease and the equipment concerned is the property of the service provider (BT), there will certainly be decent records of Bernards 12 pair cable (More likely to be 10 or 15 pair I suspect) and the BT/DP (Block terminal/Distribution point). However there is unlikely to be much record kept of the individual circuits cables connected to the DP unless there is any sort of, registered, third party agreement.

    OP has managed a reasonable description
    He seems to have a reasonable understanding of where the cables go
    and then he starts on his proposed actions
    I doubt there will be any 'not connected' cables but it's a a starting point.

    From OP it sounds like the property used to have non domestic use and a number of cables follow the same route from the DP to where they enter the building via the porch... My apologies if I have interpreted the information incorrectly.
     
  8. SUNRAY

    SUNRAY

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    Yes you are correct, from an 0171 line to call an 0171 number one only had to use the 7 digit number, just the same as calling between any other two exchange areas. However to call an 0181 number (from 0171) one had to use thew whole 11 digit number - just like calling between any other two exchange areas.
    In preparation for the changeover to 020 one had to use the whole 11 digits (0171 & 0181), regardless of where calling from. The 020 code was introduced (very probably put into place at the same time) but publicised a little while later, for a long while both codes were in place with the promise that only the 8 digits would be required after full changeover. when calling within 020 area.

    I'd be surprised if final changeover from Strowger was as early as 1996 (as mentioned) as I was aware of bits of Strowger being added around 1990 in a building containing Strowger & System X, I can't help thinking they'd have done everything possible to not install old technology during a concerted effort to remove the same kit. There was certainly Strowger kit still in place with lights on past 2002, visible through a window when I pointed out to someone where I'd worked but of course I have noe idea if it was still active, past experience says old kit was removed very quickly.
    That said 1990 was the last I worked for London Telephones and I have no direct working knowledge since then.
     
  9. SUNRAY

    SUNRAY

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    It was very confusing for the public to comprehend as their number had been 7 digits for decades.
     
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  11. winston1

    winston1

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    There was never an 0207/0208 plus 3 and 4. It went straight to 020 plus 4 and 4. Why would anyone be confused adding an extra digit to their number? There was loads of publicity about it at the time from BT if one cared to read it.
     
  12. SUNRAY

    SUNRAY

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    Technically you are correct, officially and as far as the public were concerned the code and number went from 0171 plus7 to 020 plus8 etc. The practicalities of the changeover were a different matter which is why the numbers became 11 digit for the duration of the changeover.

    Even now, 20+ years on many of the public still don't understand the correct number, but it doesn't matter in the slightest.
     
  13. wgt52

    wgt52

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    Was in Croydon SS in '98 setting up a national test network, AFAICR there was 2 floors of Strowger powered up but unused in that building. The site manager told me they only cleared the floor a matter of days before the CB platform boxes were installed, had to run CAT5 and co-ax cables down about 4 floors just set the data comms link up. Seems London just left the kit there until until sold for reuse or the scrap merchants recovered it.
    Last Strowger I saw working was in 2003/4 but that was an independent network. I'd moved on from telephones by then.
     
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  14. Robin0577

    Robin0577

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    Personally, I use a simple analogue corded phone with a crocodile clip lead for line testing. The sort of phone you can get in Argos for 6 or 7 quid. When you find a live pair, you'll get a dial tone (or other tone on newer data only lines). Once you have a dial tone, dial 17070 to identify the line, a computerised voice will speak the phone number to you.
     
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  15. securespark

    securespark

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    A great way to test the bell circuit in the absence of test equipment.

    It used to be 170.
    IIRC, before that, the SALT test was 174.

    There were other engineer Xchange test numbers like 175 and 177, but I never knew what these did.
     
  16. bernardgreen

    bernardgreen

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    SALT = Subscriber automatic line test were very useful.

    information extracted from https://www.gbnet.net/net/uk-telecom/p3-15.html

    SALT Dial 175
    Await ringback and listen for tone.
    Dialtone=OK Engaged=Suspect Faulure=Fault

    Dial next test if required, tests as follows:
    2 Low A/B Insulation test |
    3 A/B to earth | Insulation tests
    4 A/B to battery |
    5 A/B loop to earth |
    9 Bell answer before 5th ring
    11 SPM test
    7 Loop Res test
    8 Dial test. LD Dial 0. MF Dial 1-9 0
    10 Rec all pre
    6 Line reversal for diode check

    Dialtone=OK Engaged=Suspect Faulure=Fault
     
  17. Robin0577

    Robin0577

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    Also note that on some, usually older phones with electromechanical bells, the bell function requires the NTE master socket to be in circuit, and a third wire to be connected because the master socket contains the bell capacitor.

    Most cheap modern phones have solid state electronic bells and do not need the capacitor and will work just fine connected directly across the incoming line. (Any phone which is supplied with a 2 core only cable clearly doesn't need the third connection)
     
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