When BT do FTTC ?

Discussion in 'Broadband' started by David, Jul 28, 2010.

  1. BT always seem to send two vans, one to pull, one to terminate. a helper
    with each and a bloke standing around drinking tea or criticising :)
    I meant the electrical gubbins.
    In the good old days we would aggregate about 10 people at bandwith X to
    a line of bandwith X and 10 of those for an upstream of 0x.

    So generally 10:1 or so.
     
    The Natural Philosopher, Jul 30, 2010
    #41
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  2. well I was workong., or in fact hanging around being miserable in a
    complete mess of a project with ICL networks stevenage.

    We were (allegedly) writing software for a repeater that was made
    somewhere else by STL or STC.
     
    The Natural Philosopher, Jul 30, 2010
    #42
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  3. David

    Petert Guest

    I remember having contact with the STC software types at Stevenage in
    1993/94, justvprior to STC closing it.
    --
    Cheers

    Peter

    (Reply to address is a spam trap - pse reply to the group)
     
    Petert, Jul 31, 2010
    #43
  4. David

    Petert Guest

    I think those days are now history
    What electrical gubbins?
    Sorry, that's just flown over my head at a substantial rate of
    knots!!!!!!!!!!!!
    --
    Cheers

    Peter

    (Reply to address is a spam trap - pse reply to the group)
     
    Petert, Jul 31, 2010
    #44
  5. What took them so long?

    I have never seen a more clueless bunch of twats frankly, and that was
    about 1988..
     
    The Natural Philosopher, Jul 31, 2010
    #45
  6. An ETSI CC7 style 2.048 million bits/sec (or 2,048 thousand bits/sec)
    (aka "2-meg") digital path carries 32 x 8 thousand bytes/sec (or 64
    thousand bits/ sec) channels. It's never described as 2,048 Khz though
    (at least, not by anyone who actually works with them that I ever met,
    either within Ericsson's or the numerous operators on whose sites I worked).

    More accurately, it has 32 x 8 bit timeslots available every 1/8000 of a
    second.

    Timeslot 0 is used for synchronization and link control.

    Timeslot 16 usually either carries traffic control and inter-exchange
    signalling when ex nationalised PTTs are involved, or is left unused
    (you don't need 1 signalling cct per 30 traffic ccts, normally 1 per
    2000 or so will suffice).

    Timeslot 16 is however often used as a traffic slot in the internal
    networks of operators who haven't inherited PTT mentality.

    Leaving timeslot 16 unused makes it marginally quicker to swing a
    signalling connection from a failed 2-meg to an alternative, but most
    networks are configured with more signalling capacity than they need
    such that a single failed signalling link or terminal won't cause
    traffic loss through congestion in the signalling network anyway.

    In ANSI SS7 based systems, a digital path carries 1.536 kbits/sec, as 24
    x 8 bit timeslots every 1/8000 of a sec, but synchronization, link
    control and signalling use 1 bit from every timeslot, so the traffic
    circuits are 56,000 bits sec, and when carrying analog traffic, use a
    different ADC encoding to that on ETSI CC7 systems.

    Conversion racks typically interface 3 ETSI CC7 systems to 4 ETSI SS7
    systems (96 traffic circuits on each side).

    Rgds

    Denis McMahon
     
    Denis McMahon, Aug 2, 2010
    #46
  7. Nonononono

    It's not a frequency. Don't express it as a frequency.

    2,048,000 bits / sec is not 2,048,000 khz.

    It's like saying you put 3 metres of petrol in your car, Or you have 3
    kilograms of free space on your hard drive, or ordering 25 watts of beer
    in the pub.

    Rgds

    Denis McMahon
     
    Denis McMahon, Aug 2, 2010
    #47
  8. Meh, I knew something looked wrong when I wrote 1.536, but I was only
    involved in setting up E1/T1 conversions once, and it was some time ago.

    Rgds

    Denis McMahon
     
    Denis McMahon, Aug 3, 2010
    #48
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