The CooVox-U20 IP Phone System is the second generation of Mini IP Phone System launched by ZYCOO, meanwhile it's the first Mobile IP Phone System with the ability to use the GSM or UMTS (3G) module to connect to the mobile network for data transfer.

CooVox-U20 is a next-generation smart IP PBX System designed and optimized for today’s business telecommunication needs. CooVox-U20 is an affordable, scalable, interoperable, secure and reliable solution which provides not only traditional PBX features such as Automated Attendant and Voicemail, but also many advanced features including Remote Extensions, Remote Office Connection, Conference Bridge, Call Recording, Call Detail Records (CDR), Automatic Call Distribution (ACD), Unified Messaging (Voicemail to Email), and many more features.

CooVox-U20-A202 2 0
CooVox-U20-A211 1 1

GSM or UMTS (3G) is optional for configuration


Call Features
Call Back
Call Forward
Call Hold
Call Paging and Intercom
Call Park
Call Pickup
Call Queue
Call Recording
Call Routing
Blind Transfer 
Attended Transfer
Call Waiting
Caller ID
Dial by Name
Music On Hold/Transfer
3-Way Conference
Video Call

PBX Features
Black List
BLF (Busy Lamp Field)
CDR (Call Detailed Record)
Conference Room (3 Rooms)
Call Monitoring
DID (Direct Inward Dialing Number)
DISA (Direct Inward System Access)
Distinctive Ringtone
DND (Do Not Disturb)
DNIS (Dialed Number Identification Service)
Feature Codes
FOP (Flash Operation Panel) Status Monitoring
Follow Me
IVR (Interactive Voice Responses)
Mobility Extension
Multi-Language Prompts
Multi-Language GUI 
One Touch Recording
Phone Book
Phone Provisioning
Pin Set
Record File Download
SIP Register with UDP/TCP/TLS
SIP Trunk 
Skype for SIP
Smart DID
Speed Dial
SRTP (Secure Realtime Transport Protocol)
T.38 Fax (Pass-through)
Time Based Rule
Virtual Fax 
Voicemail & Voicemail to Email

System Capacities
10 Concurrent Calls
Up to 30 IP Phone Registers/Extensions
Recording: 21,000 mins (.gsm); 3,000 mins (.wav)
Voicemail: 21,000 mins (.gsm); 3,000 mins (.wav)

Codecs & Protocols
Audio Codecs: G.722/G.711-Ulaw/G.711-Alaw/G.726/G.729/GSM/SPEEX
Video Codecs: H.261/H.263/H.263+/H.264
Protocols: SIP (RFC3261)/IAX2 

Network Features
DDNS Client 
DHCP Server
IP Assignment (PPPoE/DHCP/Static)
SNMP v1/v2
Static Route Table
Trouble Shooting (Ping/Traceroute)
PoE (Power over Ethernet)
VPN Client (N2N/L2TP/PPTP/OpenVPN)
VPN Server (PPTP/L2TP/OpenVPN, Up to 10 Users)

Security Features
Refuse SIP Register DoS
Refuse Abort Invite DoS
Refuse SSH Login DoS

Web Access Log
PBX Debug Log


Hardware Interfaces

1 Reset Button
1 Power Interface 
1 Ethernet Interface 
2 Analog Ports (FXO/FXS)
1 Interface for Optional UMTS Module

Hardware Specifications
Processor: DualCore A7(1GHz)
Processor: DualCore 500Mhz DSP
Storage: 4GB SD Card
Power Supply: Input AC 100~240V, 50/60Hz;Output DC 12V/1A

Working Temperature: 0 ~ 40°C
Storage Temperature: -20 ~ 55°C
Humidity: 5 ~ 95% Non-condensing


Applicable Modules


FXO-200  FXS-200 FXOS 1GSM 1UM


Inner Box Dimension 320 mm × 170 mm × 80 mm
G.W./Unit 0.8 kg
Carton Dimension 340 mm × 330 mm × 330 mm
Units/Carton 10 Units
G.W./Carton 10 kg


Name Version Size Release Date Download
CooVox-U20 Datasheet V1.0 868.16 KB Aug. 29, 2014
CooVox Series User Manual (Admin) V1.1.1 3.32 MB July. 06, 2014
CooVox Series User Manual (Ext. User)V1.1.1 V1.1.1 875 KB July. 06, 2014
Secure Your CooVox V1 IP Phone System V1.2.0 V1.2.0 866.30 KB Apr. 29, 2016
CooVox-Module Setting Guide V1.0 1.39 MB Feb. 04, 2015
CooVox-U20 QIG V1.0 852.80 KB Aug. 29, 2014
CooVox-U20 Firmware V1.2.0 V1.2.0 7.75 MB May. 13, 2016
CooVox-U20 Firmware V1.1.0 V1.1.0 4.61MB Dec. 10, 2014
CooVox-U20 FirmwareV1.0.5 V1.0.5 12.7 MB Aug. 29, 2014
CooVox-U20 FirmwareV1.0.5 Patch1 V1.0.5 770.21 KB Aug. 29, 2014
CooVox-U20 FirmwareV1.0.5 Patch2 V1.0.5 3.42 MB Aug. 29,2014
CooVox-U20 FirmwareV1.1.1 V1.1.1 6.23 MB Apr. 08, 2015
CooVox-U20 FirmwareV1.1.2 V1.1.2 6.79 MB Dec. 22, 2015
CooVox-U20 Security Patch V1.0 1.70 MB Jan. 27, 2016