CHAPTER 15
COMMUNICATIONS, LIFE SAFETY AND SECURITY SYSTEMS
OVERVIEW
This chapter covers the engineering of low-voltage auxiliary systems in buildings. Covering
basic wiring for all forms and functions of information systems, security systems, closed-circuit
television and fiber optics, this chapter establishes rules of thumb for the design and wiring of
distributed systems. Special emphasis is placed on the importance of signal quality matching the
impedance of transmission wiring to the frequencies called for by the terminal equipment.
Included in this chapter is a review of the fundamentals of systems electronics including a
discussion of the properties of digital and analog systems and the commonly used wiring that
support them. Each of the commonly used media is reviewed from the standpoint of their
infrastructure requirements with special emphasis on those related to compliance with building
codes.
Of critical importance is the understanding of efficient and flexible distribution of auxiliary
systems across the building infrastructure. The Selection of Wiring Systems section details the
wire-speed and transmission capacities of traditional twisted-pair cabling groups, coaxial cable
and fiber optic systems. Electronic Industry Association (EIA) standards for the category
specifications for shielded and unshielded twisted pair (STP and UTP) are covered in detail, as
are the standards for coaxial and RGB cable. A brief section on fiber optical transmission
includes the specifications governing light ray transmission such as index of refraction and
critical angle, together with guidelines for the connectors and splicers associated with
multiplexing.
The section on Telecommunications Systems describes and illustrates the principles of
distributed telecommunications systems, network topologies and the classes of wiring
infrastructure that support them. The basics of telephone systems are covered including Private
branch Exchange (PBX) switching. Direct Outward Dialing (DOD) and Direct Inward dialing
(DID). Included are the range of applications for telecommunications cabling and the structural
wiring used to meet the service standards of voice, data and video transmission over local and
wide area networks (LAN/WAN). This chapter describes and discusses network topologies and
their impact on the availability of bandwidth and signal quality. Wide Area Networks, Virtual
Private Networks and the Internet are discussed in light of network segmentation strategies that
deploy an array of systems options such as traditional leased lines and today’s packetized and
switched modes of high-speed transmission. Also covered are the fundamentals of wireless
communications systems including the infrastructure issues related to broadcast and “on–
premises” wireless networks?
CHAPTER 15
COMMUNICATIONS, LIFE SAFETY AND SECURITY SYSTEMS
QUESTIONS AND ANSWERS
15.1 What are the six major communications systems found in buildings?
2. Video TV, CATV, MATV, SATV, etc.
4. Data modem, local area network, wide-area network, wireless, etc.
6. Multimedia combination of audio/video/ telephone and data, such as videoconferencing
and distance learning systems.
15.2 What are the four major classifications of building operational systems?
Four major building operational systems:
1. Safety fire alarm, sprinkler alarm, emergency evacuation, etc.
2. Security access control, video surveillance, intrusion detection, etc.
15.3 Why is it not necessary to install telecommunications wiring in conduit?
15.4 What is the difference between analog and digital signals? Can they be converted
from one to the other?
15.5 What are the forms and functions that can be provided by radio, TV and computer
systems?
15.4 Human hearing frequency extends over 10,000 Hz. What is the highest frequency
that can normally be transmitted by a conventional telephone system?
15.6 What are commonly used wires for telecommunications systems?
15.7 What is fiber optics? What is an optic fiber?
15.8 Name several advantages of an optic fiber comparing with twisted pair or coax
cables?
15.9 What is meant by critical angle in an optic fiber?
1.0 (n2 = 1.0). What is the critical angle when light passes from glass to air?
15.10 What are the metal compounds commonly used to generate laser in fiber optic
systems? What is the range of wavelengths in nanometers (nm)?
15.10 What is the applicable transmission speed range in Mbps for a coax cable? A single
mode optic fiber?
15.11 What are the frequency bands assigned for FM radio in the USA? VHF/TV
channels (2 to 6)? Cellular telephones? Satellite UHF?
15.12 What is meant by geostationary type telecommunication satellite? What is it’s orbit
(miles above the earth)?
15.13 Why is the angle of a satellite receiving station lower in Alaska than in Florida?
15.14 What is a LAN? A WAN?
15.15 Name the card installed in a PC workstation to connect it to a LAN or WAN.
15.17 What are the disadvantages of wireless LAN?
15.18 What is the function of structured wiring?
15.19 What are the design elements that comprise structured wiring?
1. Entrance facilities (i.e., conduits, manholes, and armored cables)
2. Equipment rooms, including construction and space requirements
4. Backbone wiring, including risers and the infrastructure
6. Work area
15.20 What are the common techniques used in access control?
15.21 What are the commonly employed principles in intrusion detection?
15.22 What are the detection devices commonly used within a building?
15.19 What are the two types of telephone dialing systems?
15.23 What is PBX, DOD, and DID in a telephone system?
15.24 What are a coded, a supervised, a zoned, and an addressable fire alarm system?
15.25 Why is flashing or strobe lights required in fire alarm systems?
15.26 What is a public address (PA) system? What are the basic components?
15.27 What size ceiling or wall-mounted speakers are normally used in buildings and what
is the approximate area of coverage?
15.28 What wire types are normally used for sound systems? Can optic fiber be used?
15.29 What is a time and program system? Where is it usually installed?
15.30 How are clocks synchronized in the time-clock system?
15.31 Name as many as you can of the telecommunication systems which should be
12.32Low voltage cabling typically does not require traditional EMT conduit. What
methods are commonly used to support low-voltage cable?
Bridle rings and cable trays otherwise referred to as cable ladder.
15.33 When would conduit (EMT) be necessary when installing low-voltage cable?
15.34 RGB cable is typically used for high-resolution video signals. What are the
individual video components carried by the RGB cable?
15.35 What are the two most common types of multimedia projectors used to display
computer graphics?