3CX BASIC CERTIFICATION (3CX) COMPLETE PRACTICE EXAM | PBX
ADMINISTRATION, VoIP, SIP TRUNKING & SYSTEM CONFIGURATION | ORIGINAL
PRACTICE QUESTIONS WITH DETAILED RATIONALES | UPDATED 2026/2027 STUDY
GUIDE
Examiner/Administrator: 3CX
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3CX BASIC CERTIFICATION PRACTICE EXAM
2026/2027 EDITION
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
COMPLETE PRACTICE EXAM
30 ORIGINAL MULTIPLE-CHOICE QUESTIONS
PASSING SCORE: 80%
TESTING TIME: 60 MINUTES
TABLE OF CONTENTS
1. VoIP Fundamentals
2. SIP Protocol Basics
3. PBX Architecture
4. 3CX Installation & Deployment
5. Extensions & User Management
6. SIP Trunks & DID Configuration
7. Call Routing & Inbound Rules
8. Security & Firewall Configuration
9. Troubleshooting & Diagnostics
10. System Maintenance & Backup
3CX CERTIFICATION PROGRAM || ALIGNED WITH CURRENT CERTIFICATION
OBJECTIVES || PBX ADMINISTRATION || VoIP NETWORKING || SIP TRUNK
CONFIGURATION || ORIGINAL PRACTICE QUESTIONS || DETAILED ANSWER
,RATIONALES || PROFESSIONAL CERTIFICATION PREPARATION || EDUCATIONAL STUDY
RESOURCE
VoIP Fundamentals (Questions 1–4)
QUESTION 1.
A company is migrating from a traditional analog PBX to a modern IP-PBX. The
network administrator explains that voice traffic will now travel over the
organization's Ethernet infrastructure rather than dedicated telephone cabling. Which
technology enables this transition?
A. MPLS VPN
B. Voice over Internet Protocol (VoIP)
C. Fibre Channel
D. SNMP
Correct Answer: B. Voice over Internet Protocol (VoIP)
Explanation: VoIP converts voice into IP packets for transmission across IP
networks, allowing telephony to operate over existing Ethernet infrastructure. MPLS
may transport VoIP traffic but is not the enabling technology. Fibre Channel is
designed for storage networking, while SNMP is a network management protocol
rather than a voice transport mechanism.
QUESTION 2.
Which protocol is primarily responsible for establishing, modifying, and terminating
multimedia communication sessions between SIP endpoints?
A. RTP
B. SIP
,C. DNS
D. LDAP
Correct Answer: B. SIP
Explanation: SIP manages session signaling, including call setup, negotiation,
modification, and termination. RTP transports the media itself after SIP establishes
the session. DNS resolves names, and LDAP provides directory services.
QUESTION 3.
Which statement best describes the purpose of RTP during a VoIP call?
A. Encrypts SIP credentials
B. Carries the audio media stream
C. Resolves SIP server addresses
D. Authenticates user accounts
Correct Answer: B. Carries the audio media stream
Explanation: RTP transports real-time audio and video packets once a call has been
established. SIP performs signaling, DNS resolves hostnames, and authentication is
handled separately through SIP authentication or directory integration.
QUESTION 4.
A network engineer notices degraded call quality caused by excessive packet delay.
Which network characteristic is most directly responsible?
A. DNS caching
B. Latency
, C. DHCP lease duration
D. VLAN numbering
Correct Answer: B. Latency
Explanation: High latency delays voice packets and degrades conversation quality.
DNS caching, DHCP lease duration, and VLAN numbering have little direct effect
on one-way voice delay.
SIP Protocol Basics (Questions 5–8)
QUESTION 5.
A SIP endpoint sends an INVITE message to begin a telephone conversation. What is
the primary purpose of the INVITE request?
A. Register voicemail
B. Initiate a communication session
C. Reset authentication credentials
D. Transfer RTP packets
Correct Answer: B. Initiate a communication session
Explanation: The INVITE request starts a SIP dialog by requesting establishment of
a multimedia session. RTP carries media only after successful signaling. Voicemail
registration and credential resets are unrelated to INVITE.
QUESTION 6.
Why does a SIP phone periodically send REGISTER messages to the PBX?
A. To upload call recordings
B. To inform the PBX of its current reachable location
ADMINISTRATION, VoIP, SIP TRUNKING & SYSTEM CONFIGURATION | ORIGINAL
PRACTICE QUESTIONS WITH DETAILED RATIONALES | UPDATED 2026/2027 STUDY
GUIDE
Examiner/Administrator: 3CX
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
3CX BASIC CERTIFICATION PRACTICE EXAM
2026/2027 EDITION
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
COMPLETE PRACTICE EXAM
30 ORIGINAL MULTIPLE-CHOICE QUESTIONS
PASSING SCORE: 80%
TESTING TIME: 60 MINUTES
TABLE OF CONTENTS
1. VoIP Fundamentals
2. SIP Protocol Basics
3. PBX Architecture
4. 3CX Installation & Deployment
5. Extensions & User Management
6. SIP Trunks & DID Configuration
7. Call Routing & Inbound Rules
8. Security & Firewall Configuration
9. Troubleshooting & Diagnostics
10. System Maintenance & Backup
3CX CERTIFICATION PROGRAM || ALIGNED WITH CURRENT CERTIFICATION
OBJECTIVES || PBX ADMINISTRATION || VoIP NETWORKING || SIP TRUNK
CONFIGURATION || ORIGINAL PRACTICE QUESTIONS || DETAILED ANSWER
,RATIONALES || PROFESSIONAL CERTIFICATION PREPARATION || EDUCATIONAL STUDY
RESOURCE
VoIP Fundamentals (Questions 1–4)
QUESTION 1.
A company is migrating from a traditional analog PBX to a modern IP-PBX. The
network administrator explains that voice traffic will now travel over the
organization's Ethernet infrastructure rather than dedicated telephone cabling. Which
technology enables this transition?
A. MPLS VPN
B. Voice over Internet Protocol (VoIP)
C. Fibre Channel
D. SNMP
Correct Answer: B. Voice over Internet Protocol (VoIP)
Explanation: VoIP converts voice into IP packets for transmission across IP
networks, allowing telephony to operate over existing Ethernet infrastructure. MPLS
may transport VoIP traffic but is not the enabling technology. Fibre Channel is
designed for storage networking, while SNMP is a network management protocol
rather than a voice transport mechanism.
QUESTION 2.
Which protocol is primarily responsible for establishing, modifying, and terminating
multimedia communication sessions between SIP endpoints?
A. RTP
B. SIP
,C. DNS
D. LDAP
Correct Answer: B. SIP
Explanation: SIP manages session signaling, including call setup, negotiation,
modification, and termination. RTP transports the media itself after SIP establishes
the session. DNS resolves names, and LDAP provides directory services.
QUESTION 3.
Which statement best describes the purpose of RTP during a VoIP call?
A. Encrypts SIP credentials
B. Carries the audio media stream
C. Resolves SIP server addresses
D. Authenticates user accounts
Correct Answer: B. Carries the audio media stream
Explanation: RTP transports real-time audio and video packets once a call has been
established. SIP performs signaling, DNS resolves hostnames, and authentication is
handled separately through SIP authentication or directory integration.
QUESTION 4.
A network engineer notices degraded call quality caused by excessive packet delay.
Which network characteristic is most directly responsible?
A. DNS caching
B. Latency
, C. DHCP lease duration
D. VLAN numbering
Correct Answer: B. Latency
Explanation: High latency delays voice packets and degrades conversation quality.
DNS caching, DHCP lease duration, and VLAN numbering have little direct effect
on one-way voice delay.
SIP Protocol Basics (Questions 5–8)
QUESTION 5.
A SIP endpoint sends an INVITE message to begin a telephone conversation. What is
the primary purpose of the INVITE request?
A. Register voicemail
B. Initiate a communication session
C. Reset authentication credentials
D. Transfer RTP packets
Correct Answer: B. Initiate a communication session
Explanation: The INVITE request starts a SIP dialog by requesting establishment of
a multimedia session. RTP carries media only after successful signaling. Voicemail
registration and credential resets are unrelated to INVITE.
QUESTION 6.
Why does a SIP phone periodically send REGISTER messages to the PBX?
A. To upload call recordings
B. To inform the PBX of its current reachable location
