Page 1 of 97
803 TECHNICAL KNOWLEDGE TEST II (TKT II) AT&T Exam
Actual Test Questions and Correct Answers With
Rationales LATEST THIS YEAR
Summarized Exam Coverage – AT&T TKT II
Telecommunications fundamentals (DS0, DS1, DS3, OC levels), multiplexing (TDM, statistical, WDM),
digital hierarchies (T-carrier, SONET/SDH), fiber optics (connectors, OTDR, loss budgets, cleaning),
Ethernet (10/100/1G/10G, VLANs, switching), IP addressing (IPv4, IPv6, subnetting), routing (static,
OSPF, BGP basics), MPLS, VoIP signaling (SIP, H.323, RTP), wireless (LTE, 5G, small cells), outside plant
(cable identification, locating, splicing, manhole safety), inside plant (central office cabling, power,
grounding), transport equipment (Ciena, Nokia, Cisco), testing (BERT, TDR, OTDR, power meter), SONET
ring protection (UPSR, BLSR), Ethernet ring protection (ERPS), circuit provisioning (TL1, craft interface),
synchronization (BITS, GPS), DC power plants (rectifiers, batteries), HVAC, security, and safety (ladders,
confined space, LOTO, HAZMAT).
1. An AT&T technician is troubleshooting a DS1 circuit with a BERT. The test shows “BPV” errors. What is
the most likely cause?
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A) Cross-talk from adjacent pairs
B) Bipolar violation due to a line coding error or physical defect
C) Excess jitter
D) Frame slip
Answer: B – BPV (Bipolar Violation) indicates that the alternating mark inversion rule was broken, often
from a short or bad transmitter.
2. A SONET OC-48 ring is configured for UPSR. How many working fibers are required for a 2-fiber UPSR?
A) 1
B) 2 (one working, one protect)
C) 4
D) 8
Answer: B – 2-fiber UPSR uses one working fiber and one protect fiber; traffic is sent both directions.
3. An AT&T central office technician measures –48 VDC at a fuse panel. The battery string is showing –52
VDC. The most likely cause is:
A) Batteries are fully charged and on float
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B) Rectifier failure causing under-voltage
C) High resistance connection or cable drop
D) Ground fault
Answer: C – Voltage drop of 4 V suggests resistance in the distribution cables or connections.
4. A field technician needs to identify a specific fiber pair in a 288-count cable in a manhole. Which tool
is most appropriate?
A) VFL (Visual Fault Locator)
B) OTDR
C) Fiber identifier with tone
D) Power meter
Answer: C – A fiber identifier with a tone (bend) allows non-invasive identification of a live fiber.
5. A technician is adding a new VLAN to an Ethernet switch. The new VLAN must be able to
communicate with an existing VLAN. What must be configured?
A) VLAN isolation
B) Layer 3 routing (SVI or router)
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C) MAC flooding
D) Spanning Tree Protocol
Answer: B – VLANs are separate broadcast domains; inter-VLAN communication requires a Layer 3
device (router or multilayer switch).
6. An AT&T technician receives a “LOS” alarm on a DS1 circuit. What is the first step?
A) Replace the CSU
B) Check for a broken or disconnected cable
C) Increase line build-out
D) Reset the far end
Answer: B – LOS (Loss of Signal) most often caused by a physical break, disconnected cable, or failed line
driver.
7. A SONET network uses BLSR with 4 fibers. How many fibers are dedicated to protection?
A) 1
B) 2
803 TECHNICAL KNOWLEDGE TEST II (TKT II) AT&T Exam
Actual Test Questions and Correct Answers With
Rationales LATEST THIS YEAR
Summarized Exam Coverage – AT&T TKT II
Telecommunications fundamentals (DS0, DS1, DS3, OC levels), multiplexing (TDM, statistical, WDM),
digital hierarchies (T-carrier, SONET/SDH), fiber optics (connectors, OTDR, loss budgets, cleaning),
Ethernet (10/100/1G/10G, VLANs, switching), IP addressing (IPv4, IPv6, subnetting), routing (static,
OSPF, BGP basics), MPLS, VoIP signaling (SIP, H.323, RTP), wireless (LTE, 5G, small cells), outside plant
(cable identification, locating, splicing, manhole safety), inside plant (central office cabling, power,
grounding), transport equipment (Ciena, Nokia, Cisco), testing (BERT, TDR, OTDR, power meter), SONET
ring protection (UPSR, BLSR), Ethernet ring protection (ERPS), circuit provisioning (TL1, craft interface),
synchronization (BITS, GPS), DC power plants (rectifiers, batteries), HVAC, security, and safety (ladders,
confined space, LOTO, HAZMAT).
1. An AT&T technician is troubleshooting a DS1 circuit with a BERT. The test shows “BPV” errors. What is
the most likely cause?
, Page 2 of 97
A) Cross-talk from adjacent pairs
B) Bipolar violation due to a line coding error or physical defect
C) Excess jitter
D) Frame slip
Answer: B – BPV (Bipolar Violation) indicates that the alternating mark inversion rule was broken, often
from a short or bad transmitter.
2. A SONET OC-48 ring is configured for UPSR. How many working fibers are required for a 2-fiber UPSR?
A) 1
B) 2 (one working, one protect)
C) 4
D) 8
Answer: B – 2-fiber UPSR uses one working fiber and one protect fiber; traffic is sent both directions.
3. An AT&T central office technician measures –48 VDC at a fuse panel. The battery string is showing –52
VDC. The most likely cause is:
A) Batteries are fully charged and on float
, Page 3 of 97
B) Rectifier failure causing under-voltage
C) High resistance connection or cable drop
D) Ground fault
Answer: C – Voltage drop of 4 V suggests resistance in the distribution cables or connections.
4. A field technician needs to identify a specific fiber pair in a 288-count cable in a manhole. Which tool
is most appropriate?
A) VFL (Visual Fault Locator)
B) OTDR
C) Fiber identifier with tone
D) Power meter
Answer: C – A fiber identifier with a tone (bend) allows non-invasive identification of a live fiber.
5. A technician is adding a new VLAN to an Ethernet switch. The new VLAN must be able to
communicate with an existing VLAN. What must be configured?
A) VLAN isolation
B) Layer 3 routing (SVI or router)
, Page 4 of 97
C) MAC flooding
D) Spanning Tree Protocol
Answer: B – VLANs are separate broadcast domains; inter-VLAN communication requires a Layer 3
device (router or multilayer switch).
6. An AT&T technician receives a “LOS” alarm on a DS1 circuit. What is the first step?
A) Replace the CSU
B) Check for a broken or disconnected cable
C) Increase line build-out
D) Reset the far end
Answer: B – LOS (Loss of Signal) most often caused by a physical break, disconnected cable, or failed line
driver.
7. A SONET network uses BLSR with 4 fibers. How many fibers are dedicated to protection?
A) 1
B) 2
