3CX Institute State-of-the-Art Certification
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationale
2026 Q&A| Instant Download Pdf.
Based on the search results, the 3CX Academy has been updated with new exam
content covering AI, transcription, call management, and system administration . The
certification process now uses a multiple-choice format . Below are practice questions
that reflect the types of topics you may encounter on the exam.
Question 1:
A company wants to deploy 3CX on a Debian-based virtual machine with 500 extensions
and expects peak concurrent calls of 150. Which minimum hardware specification meets
3CX recommendations for this deployment?
A. 2 vCPU, 4 GB RAM, 50 GB storage
B. 4 vCPU, 8 GB RAM, 100 GB SSD storage
C. 8 vCPU, 16 GB RAM, 500 GB HDD storage
D. 1 vCPU, 2 GB RAM, 20 GB storage
Answer: B. 4 vCPU, 8 GB RAM, 100 GB SSD storage
3CX recommends 4 vCPU and 8 GB RAM for deployments supporting 250-1,000
extensions with up to 150 concurrent calls . SSD storage is strongly recommended for
optimal I/O performance, particularly for call recording and database operations .
Question 2:
Which 3CX license tier includes the Call Flow Designer (CFD) and advanced queue
strategies such as weighted and longest waiting?
,A. Standard only
B. Pro and Enterprise
C. Standard and Pro only
D. Enterprise only
Answer: B. Pro and Enterprise
The Call Flow Designer and advanced queue strategies (weighted, longest waiting, priority)
are available in both Pro and Enterprise licenses . The Standard license supports basic call
queues with ring-all and hunt strategies but does not include CFD or advanced queue
management features .
Question 3:
A company is migrating from an on-premise Windows-based 3CX V18 to a cloud-
hosted Debian V20 installation. Which migration path is officially supported?
A. Direct in-place upgrade from Windows V18 to Debian V20
B. Backup the V18 Windows configuration, install V20 on Debian, and restore the
backup during the new installation wizard
C. Export only extensions via CSV and manually recreate all settings
D. Windows V18 cannot be migrated; only fresh installations are possible
Answer: B. Backup the V18 Windows configuration, install V20 on Debian, and
restore the backup during the new installation wizard
3CX supports cross-platform migration through its backup and restore mechanism . The
administrator performs a full backup of the existing Windows V18 installation, deploys a
new Debian V20 instance, and selects "Restore Backup" during the initial configuration
wizard . This preserves all extensions, trunks, rules, and settings while upgrading to the
latest version and platform .
Question 4:
Which operating system is the recommended and primary platform for new 3CX V20
deployments?
A. Windows Server 2019
B. Ubuntu 22.04 LTS
,C. Debian 12 (Bookworm)
D. CentOS 8
Answer: C. Debian 12 (Bookworm)
3CX V20 and later versions are officially supported on Debian 12 (Bookworm) as the
primary and recommended operating system . Windows installations are supported for
legacy environments but are no longer the preferred platform . Debian provides superior
stability, security updates, and performance characteristics for VoIP workloads .
Question 5:
During the 3CX installation wizard, which network configuration is required for the PBX
to correctly determine its public IP address when deployed behind a NAT firewall?
A. Static IP assignment on the internal interface only
B. Configuring the external IP address or enabling STUN to discover the public IP
automatically
C. Disabling NAT entirely
D. Using DHCP without any static configuration
Answer: B. Configuring the external IP address or enabling STUN to discover the
public IP automatically
3CX requires knowledge of its public IP address for proper SIP header formation and NAT
traversal . Configuring the external IP address or enabling STUN allows the PBX to
correctly determine its public IP when deployed behind a NAT firewall .
Question 6:
A network administrator is configuring a new 3CX PBX for a 50-user office. Which
protocol is responsible for establishing, modifying, and terminating real-time
communication sessions such as voice and video calls?
A. RTP (Real-time Transport Protocol), which carries the actual audio and video media
streams
B. SIP (Session Initiation Protocol), which handles call setup, modification, and teardown
between endpoints
C. SDP (Session Description Protocol), which describes the media capabilities of
, endpoints
D. TCP (Transmission Control Protocol), which provides reliable data delivery
Answer: B. SIP (Session Initiation Protocol)
SIP is the signaling protocol that initiates sessions, negotiates parameters, handles call
transfers, and tears down connections when the call ends . RTP carries the media, SDP
describes what media types are supported, and TCP is a general transport protocol .
Question 7:
A company wants to minimize bandwidth usage while maintaining acceptable voice
quality for internal calls. Which codec would typically offer the best balance of low
bandwidth and reasonable quality for standard business voice?
A. G.711, which uses approximately 64 kbps per call direction without compression
B. G.729, which compresses voice to approximately 8 kbps
C. G.722, which offers wideband HD voice quality but uses more bandwidth
D. Opus, which is highly flexible but may use more bandwidth when configured for high
quality
Answer: B. G.729
G.729 was specifically designed for bandwidth-constrained environments like VoIP over
WAN links, compressing voice down to 8 kbps while still sounding decent for business
calls . G.711 sounds great but uses more bandwidth, G.722 is HD quality and uses even
more, and while Opus is versatile, G.729 remains the go-to when bandwidth minimization
is the priority .
Question 8:
A technician is troubleshooting a SIP trunk that is not registering with the provider. The
technician reviews the SIP trace and sees that the REGISTER request is being sent, but
the provider is responding with a 401 Unauthorized message. Which of the following is
the most likely cause?
A. The RTP port range is blocked by the firewall, preventing media from flowing
B. The authentication credentials configured in the 3CX trunk settings do not match
what the provider expects
Practice Exam Questions And Correct
Answers (Verified Answers) Plus Rationale
2026 Q&A| Instant Download Pdf.
Based on the search results, the 3CX Academy has been updated with new exam
content covering AI, transcription, call management, and system administration . The
certification process now uses a multiple-choice format . Below are practice questions
that reflect the types of topics you may encounter on the exam.
Question 1:
A company wants to deploy 3CX on a Debian-based virtual machine with 500 extensions
and expects peak concurrent calls of 150. Which minimum hardware specification meets
3CX recommendations for this deployment?
A. 2 vCPU, 4 GB RAM, 50 GB storage
B. 4 vCPU, 8 GB RAM, 100 GB SSD storage
C. 8 vCPU, 16 GB RAM, 500 GB HDD storage
D. 1 vCPU, 2 GB RAM, 20 GB storage
Answer: B. 4 vCPU, 8 GB RAM, 100 GB SSD storage
3CX recommends 4 vCPU and 8 GB RAM for deployments supporting 250-1,000
extensions with up to 150 concurrent calls . SSD storage is strongly recommended for
optimal I/O performance, particularly for call recording and database operations .
Question 2:
Which 3CX license tier includes the Call Flow Designer (CFD) and advanced queue
strategies such as weighted and longest waiting?
,A. Standard only
B. Pro and Enterprise
C. Standard and Pro only
D. Enterprise only
Answer: B. Pro and Enterprise
The Call Flow Designer and advanced queue strategies (weighted, longest waiting, priority)
are available in both Pro and Enterprise licenses . The Standard license supports basic call
queues with ring-all and hunt strategies but does not include CFD or advanced queue
management features .
Question 3:
A company is migrating from an on-premise Windows-based 3CX V18 to a cloud-
hosted Debian V20 installation. Which migration path is officially supported?
A. Direct in-place upgrade from Windows V18 to Debian V20
B. Backup the V18 Windows configuration, install V20 on Debian, and restore the
backup during the new installation wizard
C. Export only extensions via CSV and manually recreate all settings
D. Windows V18 cannot be migrated; only fresh installations are possible
Answer: B. Backup the V18 Windows configuration, install V20 on Debian, and
restore the backup during the new installation wizard
3CX supports cross-platform migration through its backup and restore mechanism . The
administrator performs a full backup of the existing Windows V18 installation, deploys a
new Debian V20 instance, and selects "Restore Backup" during the initial configuration
wizard . This preserves all extensions, trunks, rules, and settings while upgrading to the
latest version and platform .
Question 4:
Which operating system is the recommended and primary platform for new 3CX V20
deployments?
A. Windows Server 2019
B. Ubuntu 22.04 LTS
,C. Debian 12 (Bookworm)
D. CentOS 8
Answer: C. Debian 12 (Bookworm)
3CX V20 and later versions are officially supported on Debian 12 (Bookworm) as the
primary and recommended operating system . Windows installations are supported for
legacy environments but are no longer the preferred platform . Debian provides superior
stability, security updates, and performance characteristics for VoIP workloads .
Question 5:
During the 3CX installation wizard, which network configuration is required for the PBX
to correctly determine its public IP address when deployed behind a NAT firewall?
A. Static IP assignment on the internal interface only
B. Configuring the external IP address or enabling STUN to discover the public IP
automatically
C. Disabling NAT entirely
D. Using DHCP without any static configuration
Answer: B. Configuring the external IP address or enabling STUN to discover the
public IP automatically
3CX requires knowledge of its public IP address for proper SIP header formation and NAT
traversal . Configuring the external IP address or enabling STUN allows the PBX to
correctly determine its public IP when deployed behind a NAT firewall .
Question 6:
A network administrator is configuring a new 3CX PBX for a 50-user office. Which
protocol is responsible for establishing, modifying, and terminating real-time
communication sessions such as voice and video calls?
A. RTP (Real-time Transport Protocol), which carries the actual audio and video media
streams
B. SIP (Session Initiation Protocol), which handles call setup, modification, and teardown
between endpoints
C. SDP (Session Description Protocol), which describes the media capabilities of
, endpoints
D. TCP (Transmission Control Protocol), which provides reliable data delivery
Answer: B. SIP (Session Initiation Protocol)
SIP is the signaling protocol that initiates sessions, negotiates parameters, handles call
transfers, and tears down connections when the call ends . RTP carries the media, SDP
describes what media types are supported, and TCP is a general transport protocol .
Question 7:
A company wants to minimize bandwidth usage while maintaining acceptable voice
quality for internal calls. Which codec would typically offer the best balance of low
bandwidth and reasonable quality for standard business voice?
A. G.711, which uses approximately 64 kbps per call direction without compression
B. G.729, which compresses voice to approximately 8 kbps
C. G.722, which offers wideband HD voice quality but uses more bandwidth
D. Opus, which is highly flexible but may use more bandwidth when configured for high
quality
Answer: B. G.729
G.729 was specifically designed for bandwidth-constrained environments like VoIP over
WAN links, compressing voice down to 8 kbps while still sounding decent for business
calls . G.711 sounds great but uses more bandwidth, G.722 is HD quality and uses even
more, and while Opus is versatile, G.729 remains the go-to when bandwidth minimization
is the priority .
Question 8:
A technician is troubleshooting a SIP trunk that is not registering with the provider. The
technician reviews the SIP trace and sees that the REGISTER request is being sent, but
the provider is responding with a 401 Unauthorized message. Which of the following is
the most likely cause?
A. The RTP port range is blocked by the firewall, preventing media from flowing
B. The authentication credentials configured in the 3CX trunk settings do not match
what the provider expects
