The IVCS is an integrated communications
system that solves some of the shortcomings of older
systems installed on older ships. IVCS combines the
f e a t u r e s o f s o u n d - p ow e r e d t e l e p h o n e s , d i a l
telephones, and intercommunications units into one
system. The IVCS also can interface with other
shipboard communications systems. The system
c o n s i s t s o f t e r m i n a l s ( u s e r a c c e s s d ev i c e s ) ,
accessories, and two computer-controlled Interior
Communications Switching Centers (ICSCs).
NOTE
Whenever IVCS are installed, sound-powered
telephone circuits are designated as secondary
communications circuits.
TERMINAL DEVICES
Two types of terminal devices (network terminal
and dial terminal) are used with the IVCS. The type of
terminal and the way it is connected into the system
determines the type of service that is provided to you the
user.
Network Terminal
The network terminal (fig. 4-8) provides service
comparable to that provided by sound-powered
telephone systems. By depressing one of the five
numbered push buttons, you’re connected to any one of
four networks. Each network circuit is also connected to
one of the ICSCs. The network circuits are manned for
certain shipboard operations, similar to sound-powered
telephones.
Dial Terminal
The dial terminal provides services that can be most
easily compared to that provided by a dial telephone
system. The dial telephones terminals (fig. 4-9) are
connected to ICSCs. They are used similar to a
commercial dial telephone with push-button dialing.
Terminal Accessories
There are several types of accessories designed for
use with the dial and network terminals. These
accessories include headsets, handsets, spray-tight
enclosures that permit the installation of the terminals in
exposed areas, and loud speaker units. The loudspeaker
units (fig. 4-10) are designed for use with either the dial
or network terminals. Both units are equipped with
press-to-talk switches. Additionally, by depressing the
hands-free push switch on the unit, the operator can
communicate without using the press-to-talk switch.
This permits you to communicate without a handset or
headset.
INTERIOR COMMUNICATIONS
SWITCHING CENTER (ICSC)
The ICSCs are the heart of the IVCS. They perform
the switching actions necessary to connect the calling
party to the called party, similar to the automatic
switchboards of a dial telephone system. Figure 4-11
shows the relationship between ICSC and the IVCS.
REVIEW 5 QUESTIONS
Q1. List the terminal devices used with IVCS.
a.
b.
Q2. What is the purpose of the ICSC within the
IVCS?
COMMUNICATIONS SECURITY
Learning Objective: When you finish this chapter, you
will be able to—
Identify basic communications security
procedures.
Communications security
is defined as the
protective measures taken to deny unauthorized persons
information derived from telecommunications of the
United States government that are related to national
security and to ensure the authenticity of each
telecommunication.
4-12
Student Notes:
