• Re: Old London Telephone Exchange Names [telecom]

    From Poissons 1957@21:1/5 to All on Sun Nov 14 11:32:42 2021
    Le dimanche 21 août 2016 à 23:36:36 UTC+2, Neal McLain a écrit :
    On Friday, August 19, 2016 at 9:11:51 AM UTC-5, HAncock4 wrote:

    [snip]
    In the 1950s, many small towns could have any number of
    digits. With the coming of Direct Distance Dialing, every
    local phone number had to get expanded to seven unique digits,
    with a unique exchange code within the area code. Sometimes
    it just meant padding a two or three digit number with zeros,
    but other times it meant new numbers.
    My favorite example of leading zeroes would be Nelson, Nevada, an unincorporated community in Clark County south of Las Vegas. Google
    calls it "Nelson Ghost Town". According to Wikipedia the population
    is 37. The Census Bureau recognizes it as a "census-designated place" (presumably so they can count those 37 residents).

    But Nelson has its own NPA-NXX thousand-number block: 702-291-0xxx.
    When I visited there back in the 90s, all Nelson phone numbers were in
    the range 702-291-00xx. A grand total of 100 possible numbers!
    Since all dial exchanges back then was electro-mechanical, it meant
    a great deal of new equipment and re-wiring. All of this was just
    to handle _incoming_ toll calls.
    Most of the "electro-mechanical" equipment was some variation of Almon
    Brown Strowger's "up-and-around" switch, extensively utilized by
    GenTel and the Bell System during the 50s and 60s.

    https://en.wikipedia.org/wiki/Strowger_switch

    With the introduction of nationwide toll dialing it was necessary for
    each exchange to utilize 7-digit directory numbers. An older
    3-, 4-, 5-, or 6-digit Strowger exchange would be modified to accept
    inbound 7-digit numbers by adding "dummy" leading digits. For local
    calls the dummy digits were ignored ("absorbed") at the first selector
    by digit absorbers.

    I have written about absorbers in previous T-D posts: https://groups.google.com/d/msg/comp.dcom.telecom/hUBAP8WzrNc/QYbcLVxHavMJ https://groups.google.com/d/msg/comp.dcom.telecom/eRvBdpAU62w/oNhgyqO1EXEJ

    Neal McLain

    Hello Paul.

    I do thank you for that useful post.

    I added a link in the French Wiki devoted to the Parisian old exchanges :

    https://fr.wikipedia.org/wiki/Anciens_indicatifs_t%C3%A9l%C3%A9phoniques_%C3%A0_Paris

    - see =C2=A7 6.2 and 11.3.

    Kind regards.

    Thierry COUTURE

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)