Keeping Records of Open Wire Toll Circuits

Knowing What’s Up There: Record Keeping of Open Wire Toll Plant

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Keeping records on physical open wire plant is a necessity for an amalgam of reasons, the most important being maintenance, but naturally, there come times when the system is extended, modified and removed from service.  Engineering staff and installation crews require up-to-date pole line records for convenience and labor saving methods, so constant travel back and forth to a subject section of line is unnecessary and proper alterations can be ordered from paper and later, computer CAD record-keeping.  

The essential quality of good records includes circuit assignments, specific equipment installations, special geographic land comprehension (which includes political designations, such as state, county, civic and township tax burden clarifications), geologic challenges (such as river crossings, canyons, swamps, rivers, lakes and mountain ranges) as well as many supplementary reasons for keeping tidy commentary on such minor items as pin and crossarm spacing, frequency ranges of carrier systems, insulator types, transposition styles of brackets and other terminal applications.  

Most importantly, the records are required to be “up-to-date” for obvious rationale: changes in poles removed or installed, wire gauge changes, transpositions added or retracted, drops either dead or live and terminals added or removed.  Keeping records current is the major issue with all construction and these should be updated at the Central Office where all records are kept.

I need not emphasize that the test board operators depended heavily on these records in spotting trouble, open or defective pairs on cables or aerial wire, and intermittent shorts and other problems showing up during their operational lifetimes.

Every Pole Line Has Its Shadow On Paper:

In the early days prior to mechanized pole line records (MPLRs), large plats of diagrammed cables and open wire printed on paper were common.  Most of these “maps” were hung on racks, where their long 36″ x 24″ lengths couldn’t be confined to conventional filing cabinets.  Later, low height multiple drawer lateral files confined them.  Usually, cable plats of towns, cities, townships–where congestion was typical, were of a single wire center (WC) area.  These reflected all local exchange cables spreading outward from the local central offices.  These libraries were common to Exchange Wire Centers (EWC).  Otherwise known as “local loop” facilities.  Toll cable and toll open wire specifications were kept in the Transmission Engineering offices at a phone company.  Long distance facilities were for both engineering and business needs, isolated from Exchange Wire Centers.

Aerial Wire Diagrams for Toll Systems:

Whether the system was operated by GTE, Bell, Contel, Centel, REA-financed borrowers, private companies, railways or other concerns where a communications system was necessary, the outside plant records were largely similar.  Universal codes, symbols and markings did not differ widely from company to company.  Depending upon how large the subject system represented as a service territory, one could depend upon their common nature and style.

From my experience working with Bell and GTE, I will utilize their record keeping systems.  AT&T shared much in common with the REA (since the REA and later the RUS [Rural Utilities Service] hired many former Bell and GTE personnel to create their required specifications and equipment application methods).  Additionally, the American Railway Association and its Communication Section were closely allied to common telecom symbology which AT&T had largely created and applied since the early days.  This is why I am using the aforementioned companies’ procedure in record keeping styles.

The open wire (as well as cable) layouts began with the initial engineering process and installation.  These specifications and maps then became the original record of note.  Once the lines were born, the necessary information was entered into a single plat (or as many as necessary to map the facilities) by the draftsmen (later draftspersons) or clerks at each Central Office staff facility.  The plats had to be large enough to read, captioned properly with cable or wire counts, terminal sizes, all equipment labeled and properly reconciled with the installations in the field.

 Here are some likely points to be included on a typical MPLR plat of open wire or cable:

  1.  Toll entrance cable length and gauge
  2.  Open wire pin position numbers
  3.  With first crossarm at the top of each diagram, followed by crossarms with unoccupied pins indicated.
  4.  Any special needs spacing, where conventional 24″ between arms was required.
  5.  Conductor size and type of wire (copper, aluminum, steel, copperweld, alumoweld, iron or similar).
  6. Insulator types.
  7. Spacing of pins on arm.
  8. Transposition Bracket Types.  Drop, point, phantom, pinched.
  9. Circuit frequency.
  10. Central office, repeater stations, and pole mounted repeaters.
  11. Filter location and carrier transfer sets.
  12. Protection equipment locations.
  13. Cable and wire junctions or terminals.
  14. Toll stations and junctions.
  15. Dates and work order numbers of revisions.
  16.  Pole numbers and equipment numbers.  
  17. Changes in size, types and wire positions.
  18. Pole mounted terminals and number of binding posts.
  19. Entrance toll cables and other cables of note.
  20. Tax, political and organizational boundaries.
  21.  Other utilities, phone companies, railroad facilities.

Additionally, when locating a loading coil on cables, repeaters on digital cable pair installations as well as other important features depending upon distances from the central offices, it is important to know (in feet) the distances between terminals, junctions, toll stations, repeater stations, poles supporting equipment cases, changes in size or type of wire, organizational and political boundaries.

Also important are:

  • Circuit order and dates
  • Connections at junctions
  • Carrier system assignments
  • Telegraph, alarm and special circuit requirements
  • Voice frequency circuit assignments.