Lesson 1/Learning Event 1
LESSON 1
INTERFACING OF VF CIRCUITS
TASK:
Describe the uses of interfacing equipment, principles of
power levels and impedance matching, analyze inband
signaling and the operation of signaling and the operation
of signaling devices.
CONDITIONS:
Given
information
about
the
interfacing
equipment,
principles of power levels and impedance matching, inband
signaling and the operation of signaling devices.
STANDARDS:
Demonstrate competency of the task skills and knowledge by
responding to the multiple-choice practice exercise; select
the ONE answer that BEST completes the statement or answers
the questions covering interfacing of VF circuits with 70
percent accuracy.
(This objective supports task 113-616-
1004; Perform Fault Isolation on a Single VF Circuit; 113-
616-1007, Activate a Circuit; 113-616-3062, Determine Test
Tone Level; 113-616-3075, Test Circuit for Basic Noise.)
REFERENCES:
FM 486-12, DCAC 310-70-1, Volume III, MIL STD 188-310A
Learning Event 1: NEED FOR INTERFACE
Whenever two communication systems are joined, the systems are said
to interface at their common juncture.
The signals that arrive at the
interface must transfer from one system into the other.
During the
process of information transfer, the characteristics of the signals must
remain unchanged, because any change in signal characteristics represents
distortion, and distortion may cause failure of one or both communication
systems.
The failure would not be due to equipment malfunction, but
rather the lack of understanding between the communicating parties.
Distortion is the most serious result of improper interface.
a. Information Transfer.
The two joined communication systems must
transfer information from one to the other with a minimum of distortion or
change in signal quality. Personnel who are to join the two communication
circuits at an interface must possess at least a knowledge of signal
characteristics,
the
transmission
medium,
and
the
terminating
or
reproducing devices.
1
Previous Page
