[GreenKeys] Re: telephone cable

Wed Nov 21 14:39:54 EST 2007

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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