[GreenKeys] "Long Lines" sign

[David Ross]

greenkeys folks -

  Re the "Long Lines Department" sign -  I believe that "Long Lines" was
a division of Bell Telephone that had to do with long-haul telephone
multiplex transmission.  A friend of mine used to work for Long Lines - 
he worked with the transpacific telephone cable which terminated near
Los Osos, CA.
  Back in 1979 I got a tour through that cable's terminus in Los Osos
Valley, CA -  really fascinating.  It was a "Frequency Division
Multiplex" system, a totally analog scheme which stacked up multiple
single-sideband conversations and piped them in/out over a coaxial
cable.
  Bear in mind that this was a very looooong cable -  ran from
California's central coast direct to Guam & then on to Japan (if memory
serves).  Built into the cable were many many vacuum tube repeaters,
necessary to boost that wideband analog signal over that distance.  The
repeater's power circuits were arranged in series and were powered by a
current source & current sink at opposite ends of the cable -  the
current source was of pretty low amperage, but one end had a voltage
compliance of like +3000 Volts and the other end had a voltage
compliance of like -3000 Volts -  necessary to run all those repeaters
in series in that undersea cable.

73
Dave Ross    N7EPI    ross@hypertools.com