[GreenKeys] Re: telephone cable
Don Robert House
drhouse at dls.net
Wed Nov 21 20:23:52 EST 2007
I for one enjoyed reading your history Larry. One thing we did not
mention was the use of Nitrogen bottles and air compressors and air
dryers to keep the water out of the cables.
Someone always tells me I should write a book, but few would
understand it, and most would not believe it.
Don
K9TTY
On 21 Nov 2007, at 1:39 PM, telegrapher at att.net wrote:
Old paper insulated pairs is till around in thousands of places.
Three colored wire covering, in essence, a white-blue and a white-
red. Some of the cable came in as large a bundle as 2700 pairs.
Really cramped in there. Then they went to plastic insulated stuff
with 10 colors and started with 11 pair, then 16 pair, then 24 pair
and then in multiples of 25's from that point on. All cables had
spare pairs in them because the factory had a specific "defective
pair" allocation for each cable. This defective pair list accompanied
each real of cable, if there were defective pairs.
Don's right about the testing procedure. Lots of time consumed
especially when someone, contractor or individual, farmer or whoever
it might be plows up one of these. Most are buried, at least the
direct buried stuff, less than 3 feet down. Big toll stuff that was
maintained by AT&T Long lines was much deeper.
Cable wasn't supplied in long lengths. You had to stay within limits
because of "loading" which was done with 88 mh Torroids like so many
tty folks like to have for building. Most cables and circuits, local
from the CO were designed for a 3000 ft end section which was right
out of the office or somewhere in that area anyway. Then the first
load coil was inserted and then a 6000 ft section would follow which
would be repeated as necessary. This applied to local voice
circuits. Obviously if someone lived in the middle of one of these
6000 ft sections (plus or minus footage) only a single load coil was
inserted.
At the end of each 6000 ft section was a splice such as Don mentioned.
And, to find a 6000 ft of 2700 pair cable would have been the
exception. So cable was ordered only for the distance that was
required to get from one manhole to another. At each manhole
additional cable would be spliced to the section coming from the CO.
But, they may not splice all the pairs through. Maybe there was a
couple hundred or even less that were going someplace else. Some
splice cases in the manhole may have 8-10 cables coming out of one end
while there is only one coming in to the other. It is a method of
getting telephone service from this location to houses off the main
route. The Engineer doing the job had the responsibility of wiring up
the town or area and he had to account for future development if
possible. It could give one more than an Excedrin headache.
There's lots more to this story than i'll get into but it is an
interesting one.
BTW, in the 70's they came out with Plastic insulated wires in a cable
that the interior was filled with what looked like Vaseline. Gawd was
it a mess to work with. There were other substances inserted into the
later cable as well all with the intent of preventing water from
penetrating the sheath through any type of damage. Keep in mind that
this cable wasn't just a bunch of wires run though a rubber hose.
Find someone out in your area who is working on some of that stuff and
have them show you how it's made. What a marvelous creation. The
lead sheathed cable was lead with a paper wrapping inside. Not just
newspaper but a special type f paper. Yet Lead covered cable was more
prone to failure than the PIC style. In the air it would vibrate on
it's messenger wire or where there were bends and then you get water
into it when it rains or snows. On a horizontal run the damage would
usually be localized, unless you were underground, (UGH) but aerial
stuff, especially at a bend where it started going vertical, it would
run and run and run.
Better quit before everyone goes to sleep. Lots of tales to tell
about those days working on the Line Crew, Cable splicing and Cable
repair before getting away from the outside plant.
zzzzzzzzzz
anyone awake out there anymore? Sorry i got carried away!
Larry
W0OGH
Don Robert House wrote:
> Harvey,
> The only time we used 260 volts was for a temporary turn up until
> the circuit could be redesigned. No other pairs in that binder
> group would be used for anything. I should have explained that
> better. In Chicago we had special cables used only for high
> voltage circuits it was all 19 AWG specially designed for
> telegraph, metering, and alarm types of circuits.
> Yes older PIC cable (paper insulated conductors) were and still are
> a big problem. Some of the cable in the close areas surrounding
> Chicago have had this cable buried in lead sheathing since 1918.
> You can imagine what happens when too much power is applied to
> these conductors...
> It is a nightmare. First a lot of customers are out of service.
> Next permits must be paid for to dig up roadway or land or both.
> Next the exact portion of the old cable that has the fault must be
> determined. The the cable is opened up back in both directions
> until individual conductors can be tested with the central office,
> one conductor at a time. Then the out pairs have to be tested one
> conductor at a time. Each conductor labeled because the paper no
> longer has any color coding. Then comes the careful splicing in of
> new cable, careful wrapping of each binder group and then sealing
> everything back in lead after each circuit is tested. Then putting
> the land and road back together.
> This happened in Evanston, Illinois about 7 years ago. Two
> apartment buildings were out of service for about 5 days while
> cable splicers worked around the clock in shifts to restore the
> cable. In today's world a couple of good circuits would be
> identified and loop electronics would be set up at both ends and
> the rest of the cable except for a few spare pairs would be
> abandoned.
> If access is available in conduit and or aerial the whole area can
> be converted to fiber optic technology. We no have the technology
> to recreate telegraph and alarm services over fiber and loop
> electronics. In some areas access makes this almost impossible.
> 73
> Don K9TTY
> Bell System Network Systems Engineer - Retired
> On 21 Nov 2007, at 9:43 AM, KC0NNC at aol.com wrote:
> Apparently the WE supplied multi-pair long haul cable (that was
> used by the
> regional systems) was insulated well enough to keep the 260 volts
> captive.
> Worst case, the 260 volts carried could have been laid against another
> similar circuit and we could have possibly see 2x260 = 520 volts.
> I wonder just what this primitive wire was good for ... prior to
> the plastic
> insulated wire, I assume the wire was wax impregnated wound cotton. I
> remember this wire as hand me downs when I was a kid experimenting
> with ham radio in
> the early 50's.
> It was nice copper wire, but the insulation unwound easily. I
> would assume
> the long haul stuff was sheathed in lead, probably 500 pair bundles...
> I can imagine in central offices like Chicago and Los Angeles, you
> could see
> the full 21,000 ft. Paid out in the run. and I can also imagine
> that with TTY
> circuits, when you ran into the 21k distance problem, you would
> also hit a
> repeater at that CO, and then the circuit was regenerated and sent
> along another
> 21k ft.
> Any observations as to the accuracy of my guess work, as I never had
> the
> pleasure of collecting a paycheck from the bell system.
> Thanks for starting this thread, it appears some of us can pick up
> some
> knowledge we have always wondered about.
> Harvey E. Smith
> 2020 Baculite Mesa Road
> Pueblo, CO., 81001-2456
> 719 406 9735
> fka WA0BBG
> nka KC0NNC
> HarveyEsmith at aol.com
> KC0NNC at aol.com
> 73's
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