Access Networks
1. Which of this is not a constituent of residential telephone line?
a) A high-speed downstream channel
b) A medium-speed downstream channel
c) A low-speed downstream channel
d) An ultra-high speed downstream channel
Answer: c
Explanation: A low-speed downstream channel is not a constituent of a residential
telephone line. But it might be just a two-way telephone channel. Internet can be
provided through a high-speed downstream channel in a residential telephone line.
2. DSL telcos provide which of the following services?
a) Wired phone access
b) ISP
c) Wired phone access and ISP
d) Network routing and ISP
Answer: c
Explanation: DSL stands for Digital Subscriber Line and ISP stands for Internet Service
Provider. In a Digital Subscriber Line system, the same company which provides phone
connection is also an ISP. The internet is provided through the pre-installed telephone
lines.
3. The function of DSLAM is to __________
a) Convert analog signals into digital signals
b) Convert digital signals into analog signals
c) Amplify digital signals
d) De-amplify digital signals
Answer: a
Explanation: DSLAM stands for Digital Subscriber Line Access Multiplexer and it’s used
by Telcos to convert the analog signals to digital signals for the purpose of providing
internet. The DSLAM located in a telco’s Central Office does this function.
4. Which of the following terms is not associated with DSL?
a) DSLAM
b) CO
c) Splitter
d) CMTS
Answer: d
Explanation: CMTS stands for Cable modem termination system. It is used in cable
internet access. In cable internet access, internet is not provided through telephone lines
and the companies that provide such connections don’t necessarily provide telephone
access.
5. HFC contains _______
a) Fibre cable
b) Coaxial cable
c) A combination of Fibre cable and Coaxial cable
d) Twisted Pair Cable
Answer: c
Explanation: Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a
broadband network that combines optical fiber and coaxial cable. It has been popularly
used since the early 1990s. It is stronger than the optical fiber cables and faster than the
co-axial cables.
6. Which of the following statements is not applicable for cable internet access?
a) It is a shared broadcast medium
b) It includes HFCs
c) Cable modem connects home PC to Ethernet port
d) Analog signal is converted to digital signal in DSLAM
Answer: d
Explanation: CMTS stands for Cable modem termination system. In cable access analog
signal is converted to digital signal by CMTS. In cable internet access, internet is not
provided through telephone lines. DSLAM is used by Telecom companies.
7. Among the optical-distribution architectures that are essentially switched ethernet is
__________
a) AON
b) PON
c) NON
d) MON
Answer:a
Explanation: AON stands for Active optical networks which are essentially switched
Ethernets. Each user has his/her own dedicated optical fiber line connecting to the ISP
in an AON.
8. StarBand provides __________
a) FTTH internet access
b) Cable access
c) Telephone access
d) Satellite access
Answer: d
Explanation: StarBand was a two-way satellite broadband Internet service available in
the U.S. from 2000–2015. It was discontinued from September 30 2015 due to
increasing competition from other ISPs.
9. Home Internet Access is provided by __________
a) DSL
b) FTTP
c) Cable
d) All of the mentioned
Answer: d
Explanation: Home Internet Access is provided by DSL, FTTP, and Cable. FTTP
provides the fastest speeds followed by the cable connections and then the DSLs. FTTP
is popularly used in modern connections.
10. ONT is connected to splitter using _________
a) High speed fibre cable
b) HFC
c) Optical cable
d) Twisted pair cable
Answer: c
Explanation: ONT stands for Optical Network Terminal. The ONT connects to the
Termination Point (TP) with an optical fibre cable. It translates light signals from the fibre
optic line to electric signals that the router can read.
11. Which of the following factors affect transmission rate in DSL?
a) The gauge of the twisted-pair line
b) Degree of electrical interfernece
c) Shadow fading
d) The gauge of the twisted-pair line and degree of electrical interference
Answer: d
Explanation: Because DSL is made of twisted wire copper pair, the gauge of twisted pair
line i.e. the protection and electrical interference would affect the transmission rate in
DSL. Unlike DSL, FTTP is not really affected by these factors
