[GreenKeys] Re: Model 15s with holding magnets...

[Don Robert House]

A COUPLE OF TYPOS....  I am getting old....

On 21 Nov 2007, at 12:45 PM, 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 NOW 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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