The table below details several features and specifications of the A-Series IP Phones.
Please also review the A-Series IP Phones Datasheet for additional detail.
You may also wish to visit the A-Series Phones for Asterisk Product Page or our A-Phones Overview support article for links to related resources.
| A20 Entry-level | A22 Entry-level gigabit | A25 Mid-level gigabit | A30 Executive-level gigabit |
Line Registrations | 2 | 2 | 4 | 6 |
Feature Keys | 1 | 1 | 5 | 7 |
Rapid Dial/BLF | 1 key | 1 key | 6 keys | 10 keys |
Ethernet LAN and PC port | 10/100 BASE-T | 10/100/1000 BASE-T | 10/100/1000 BASE-T | 10/100/1000 BASE-T |
Display | 2.8” color | 2.8” color | Main: 2.8” color BLF: 2.4” color | 4.3” color |
Power over Ethernet (PoE) | Yes | Yes | Yes | Yes |
Electronic Hookswitch Support | Yes | Yes | Yes | Yes |
Context-Sensitive Soft Keys | 4 | 4 | 4 | 4 |
Navigation Controller | 5-way | 5-way | 5-way | 5-way |
Additional Buttons | Headset, speaker, and mute keys | Headset, speaker, and mute keys | Headset, speaker, and mute keys | Headset, speaker, and mute keys |
LED Message-Waiting Indicator | Yes | Yes | Yes | Yes |
Connections |
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Phone Features
Auto-answer
Headset-answer
Headset-ring
Distinctive ring
Call waiting
Call transfer (blind & attended)
Call forward
Call hold
Intercom / Paging
Message Waiting Indication (MWI)
Busy Lamp Field (BLF)
3-way conferencing
Do Not Disturb (DND)
Redial
Call timer
Caller ID display
SIP / VoIP Support
SIP v2
SDES Secure RTP
DTMF, RFC2833
SIP peer-to-peer
SIP presence (Subscribe/Notify)
Per-account digit map/dial plan
Dial using SIP server
Secure SIP authentication
Provisioning
DHCP Option 66
XML Configuration
Phone GUI
Phone UI
Management
Digest authentication login to phone web UI
Firmware update via browser
Factory restore via GUI
Remote logging via Syslog
Audio Features
Handset, speaker, and headset modes
Full-duplex HD speakerphone with echo cancellation
Hearing aid compatible
Wideband: G.722 on all models. The A30 also supports Opus.
Narrowband: G.711 ulaw/alaw, G.726 and G.729a on all models. The A30 also supports iLBC.
Background noise suppression
Multicast audio playback
Network Support
Static or DHCP IP address assignment
NTP time synchronization
Priority queueing
Manual and LLDP-assigned VLAN
NAT traversal
QoS
802.1X authentication
Language Support
Dutch (A20/22/25 only)
English
French
German
Italian
Portuguese (A20/22/25 only)
Russian
Spanish