INTRODUCTION TO TRUNK GROUP SIZING
Critical Task: 01-5710.07-0001
In this lesson, you will learn how to determine the trunk group sizing in support of EAC.
TERMINAL LEARNING OBJECTIVE:
Determine a trunk group sizing.
You will have this lesson material, paper, pencil, and no supervision.
To demonstrate competency on this lesson, you must achieve a minimum of 70
percent on the subcourse examination.
Many times signal officers simply install systems and circuits. They may not understand the process it
takes to plan and engineer those systems. Most signal officers take for granted that someone has taken
the time to program the proper number of trunks between switchboards. Many times we tried to install
the same number of circuits and trunks that worked in the previous exercise.
1. The tendency to do as we have done in the past can be a costly waste of resources. These resources
are in the form of equipment; personnel; repair parts; petroleum, oils, and lubricants (POL); food for
personnel; and increased accident rate.
2. A tactical communications network is defined by its nodes and by the trunk group linking these
nodes. Nodal circuit switches are complex; currently we use the AN/TTC-39A as the primary nodal
circuit switch. The network also includes several other switching facilities. Large extension switches
(LES) and small extension switches (SES) serve subscribers too far away from major nodal switches to
be directly connected. Most of these switching facilities will be unit level circuit switches of various