Schematics, as Output
David Fensterheim
Formula Software Services, Ltd., 35 Reiness Street, Israel 43374
Abstract
Public utilities such as telephone, electric, gas and water companies are using AM/FM
(Automated Mapping / Facility Management) systems to manage their networks.
AM/FM technology combines a graphic/ geographic interface with a relational database
to manage a companies facilities and to track how cables and other facilities are
connected. These systems shorten the time required to design new network and generate
engineering work orders.
Traditionally an operator used an AM/FM system to produces maps and reports. In
addition to maps, however, it is often necessary to produce details of how a network is
connected. Schematic diagrams legibly display details of how items of plant are
connected. In order to present these details clearly, the graphics is oriented logically
rather than geographically. The schematic linework is typically drawn manually and
connectivity information is entered during this process.
This paper presents an automatic schematic generator. A schematic generator not only
saves the time required to draw the schematics but makes operations, such as connecting
cables and inspecting connectivity, more efficient. Complex connection scenarios may
be automated since all data entry is alphanumeric.
Traditional Schematics in Telecommunications (Outside Plant)
Connectivity diagrams are particularly important in the design and management of
communications networks. A telephone cable may contain any number of wires or
fibers. Each wire pair or range of pairs/fibers maybe connected to a range in a
connecting cable.
Imbedded Details
Various attempts are made to display the connectivity of a telephone network on a
geographic network map. Details displaying the connectivity (pair counts, joints, etc.) of
a specific location (e.g. hole, pole) are drawn on the map on or near the junction location.
All connections occurring at the location are drawn on the detail.
In order to avoid considerable clutter, the details are drawn at a scale only legible when
viewing the detail only. When displayed on a computer screen, the viewer must zoom in
so that the diagram fills the screen. When plotting a map at a typical scale (1:500 or
1:1250) the details become illegible.
Off Map Details
To solve the clutter problem, these diagrams are often drawn off the map as separate
details. In some systems, a continuous joint diagram of an entire phone network is
drawn.
Tables
Where each cable is uniquely identified, a table maybe created which lists the wire/fiber
assigmnents. At Bezeq’s northern district in Israel, a table for each joint is produced
resembling the following chart. The number of columns correspond to the number of
feed and fed cables. Tables for a number of joints maybe horizontally chained showing
the continuity of a main cable or trunk.
This format was adopted into Bezeq’s AM/FM system as both a report form as well as a
data entry form for defining connectivity. This method however does not provide a clear
graphic diagram which would convey the information in a more legible format.
Problems
Manual Detail Entry
Whether a detail is drawn on the geographic map or off the map, they are usually entered
into the AMIFM database by manually drawing graphics. The detail graphics may be
linked to the geographic graphics thereby allowing the application to display the detail of
a geographic object or visa versa.
In a typical placement scenario:
- Strand data and cables are placed on the map
- On a separate area of the graphics space, a detail is drawn of a manhole or pole and
the associated joints.
- Lines representing the cables (previously placed geographically) are drawn to the
detail.
- Lines are drawn connecting the cables during which time the user specifies the
specifics of the connection (pair count etc.).
This process is both time consuming and restricting. It is time consuming since what
would normally be simple data entry becomes a matter of drafting. It is restricting since
connectivity must always be defined the same way.
