The document discusses key concepts in telecommunications. It defines frequency as it relates to human communication and the range humans can perceive. It explains how capacitance affects telephone circuits and solutions to address issues. The decibel is used to measure signal strength given the large range of sounds. It also describes how receivers convert electrical signals to sound waves and how switches handle incoming calls. Finally, it defines interoffice trunk connections and industry terms like LATA, IntraLATA, InterLATA, ILEC, and CLEC.

1. ELET 4315 Homework #1 (Chapters 1 – 3)
Chapter 1
Explain the term frequency as it pertains to human communications.
Frequency is a term used every day to explain how often something occurs. Frequency in human
communication is one of the three major components of a sound wave, it is used to define the
different sounds we are able speak, hear, make, and perceive.
What is the minimum frequency a human being’s eardrum is able to perceive?
20 Hz
What is the maximum frequency a human beings eardrum is able to perceive?
20 kHz
Explain the effect of capacitance on a telephone circuit.
Capacitance affects the rate at which the signal attenuates, the longer the line runs, the greater the
loss of the AC signal, especially at higher frequencies. The distance the signal can travel is
reduced due to the amount of ohms that are formed from the capacitive reactance of the
telephone line, in other words, capacitive reactance increases the signal attenuation, of loss of
higher frequencies on the line. These higher-frequency AC waveforms are stored by the
capacitor, therefore heating up the line and consequently using up additional energy.
What solutions are available to help eliminate the problems associated with capacitance?
When designing a circuit longer than 1800 feet, inductors are places every 6000 feet to eliminate
frequencies higher than 3 kHz. Inductance cancels out capacitance and vice versa, a device called
a load coil is us to cancel out the capacitive reactance.
Why is the decibel used in telecommunications to measure signal strength?
The range between the softest sounds humans can hear and the loudest their eardrums can
tolerate is one-thousand-trillionth (0.00000000000001) of a watt to one-thousandth (0.001) of a
watt. Understandably, measuring change in watts within this range is impossible thus require an
alternative way to determine signal strength. The decibel to relate the increase of a power to a
logarithmic value instead of adding and subtracting exponents

2. Chapter 2
Explain how the receiver converts the electrical wave into a sound wave in the standard
telephone set.
The receiver is the device that the electrical voice signals and converts it into pressure waves-the
human voice. This can be viewed as transducers- devices that convert one form of energy into
another. Carbon granule transmitters are still common in wired home phones. Sound travels in
waves that are actually variations in air pressure. Some of these waves enter the mouthpiece and
cause a diaphragm in the transmitter microphone to vibrate back and forth. These vibrations put
either more or less pressure on carbon granules in the base of the microphone. If more pressure is
applied, the granules pack more tightly and conduct electricity more efficiently. Inversely, in
between the waves the granules unpack and do not conduct as well. Voltage is applied across the
electrical contacts and the varying amounts of resistance caused by the carbon granules in the
microphone cause varying amounts of current to flow. This current variation is an electrical
representation of the sound waves (voice=analog signal) entering the microphone. The telephone
handset receiver is just a simple speaker. It performs the opposite function of the transmitter in
that it takes the incoming electrical signal and converts it to sound waves that can be heard by the
listener. The incoming electrical signal flows through a magnetic coil in the speaker. The
magnetic field surrounding the coil changes in conjunction with the changing current flowing
through the coil. This changing magnetic field causes a cone in the speaker to vibrate. These
vibrations create air pressure waves forming sound.
Explain how the switch handles incoming calls.
It determine whether or not the telephone number belongs to one of the customers served by the
switch or if it needs to travel to route the call. There are three possible routes: to a line within the
switch, onto a trunking circuit that connects to another local central office switch, or onto a
trunking circuit that connects to the toll switch or directly to the long distance telephone
company’s switch.
Where is an RJ11 jack found in the network
The RJ11 modulation jack is found located on the wall in the customer home.

3. Chapter 3
Explain what is meant by the term interoffice trunk connection.
An interoffice trunk connection is a direct trunk between the local centraloffices in the same exchange
Define the term LATA.
Local access and transport area. Geographic areas defined after the Modified Final Judgement
in 1982. The telephone network is divided into 161 LATAs
Define the term IntraLATA.
Calls that travel between LATAs and are carried by long distance telephone carriers.
Define the term InterLATA.
Calls that travel within a LATA , they may have long distance charges
What is the difference between an ILEC and a CLEC?
“ILEC” is the abbreviated form of “Incumbent Local Exchange Carrier,” and “CLEC” is the
short form of “Competitive Local Exchange Carrier.” The ILEC and the CLEC were formed
soon after the Telecommunications Act of 1996. It was the breakup of the monopoly of AT&T
and the Bell Systems in 1984 that led to the ILEC and CLEC.
The Incumbent Local Exchange Carrier is a company that is characterized by providing local
telephone service. The ILEC owns most of the loops and facilities in a servicing area. The
Competitive Local Exchange Carrier is companies that are known to provide an alternative
service to the ILEC within its territory. CLEC is a combination of new competitors in the field.
A Competitive Local Exchange Carrier is those companies that have rented space from the
Incumbent Local Exchange Carrier.
The CLEC is always in competition with the ILEC which is an already-established, local
telephone provider. One basic difference between an Incumbent Local Exchange Carrier and a
Competitive Local Exchange Carrier is that the ILEC provides service to the public, and the
CLEC has the right to compete for that business but is not indebted to provide the same plane of
service.
An Incumbent Local Exchange Carrier can also be said to be a service provider in a specific
geographic area. For example, the old AT&T is an ILEC that provides service to a particular
region.
Different laws and rules govern both the ILECs and CLECs. The regulations for CLECs are quite

4. different from ILECs.
1. “ILEC” is the abbreviated form of “Incumbent Local Exchange Carrier,” and “CLEC” is the
short form of “Competitive Local Exchange Carrier.”
2. It was the breakup of the monopoly of the AT&T and Bell Systems in 1984 that led to the
creation of the ILEC and CLEC.
3. One basic difference between an Incumbent Local Exchange Carrier and a Competitive Local
Exchange Carrier is that the ILEC provides service to the public, and the CLEC has the right to
compete for that business but is not indebted to provide the same plane of service.
4. The Incumbent Local Exchange Carrier is a company that is characterized by providing local
telephone service. The Competitive Local Exchange Carrier is companies that are known to
provide an alternative service to the ILEC within its territory.
5. A Competitive Local Exchange Carrier is those companies that have rented space from the
Incumbent Local Exchange Carrier.
6. ILEC is the local telephone company that serves an area before the 1986 Telephone Act. The CLEC
evolved as a result of the 1986 Telephone Act. They compete with ILECs as local exchange services,
building switches and offering dial tone but using the ILECs wire facilities to provide services to
subscribers served by the ILEC’s Companies.