> HD voice: HD handset, HD speaker
> Wideband codec: Opus, G.722
> Narrowband codec: G.711(A/μ), G.729AB, G.726, iLBC > DTMF: In-band, Out-of-band (RFC 2833) and SIP INFO > Full-duplex hands-free speakerphone with AEC
> VAD, CNG, AEC, PLC, AJB, AGC

Phone Features

> 2 VoIP accounts
> Call hold, mute, DND
> One-touch speed dial, hotline
> Call forward, call waiting, call transfer
> Group listening, SMS, emergency call
> Redial, call return, auto answer
> Local 3-way conferencing
> Direct IP call without SIP proxy
> Ring tone selection/import/delete
> Set date time manually or automatically > Dial plan
> XML Browser, action URL/URI
> Integrated screenshots
> RTCP-XR
> Enhanced DSS Key

Directory

> Loal phonebook up to 1000 entries > Black list
> XML/LDAP remote phonebook
> Smart dialing

> Phonebook search/import/export
> Call history: dialed/received/missed/forwarded

IP-PBX Features

> Busy Lamp Field (BLF)
> Bridged Line Apperance (BLA)
> Anonymous call, anonymous call rejection > Hot-desking, voice mail
> Flexible seating
> Call park, call pickup
> Executive and Assistant
> Centralized call recording
> Visual voice mail
> Call recording

Display and Indicator

> 132 x 64-pixel graphical LCD with backlight
> LED for call and message waiting indication
> Dual-color (red or green) illuminated LEDs for

line status information
> Intuitive user interface with icons and soft keys > Multilingual user interface
> Caller ID with name and number
> Power saving

Feature keys

> 2 line keys with LED
> 6 features keys: message, headset, redial,

transfer, mute, hands-free speakerphone > 6 navigation keys
> Volume control keys

Interface

> 2 x RJ45 10/100M Ethernet ports
> Power over Ethernet (IEEE 802.3af), class 1 (T21P E2) > 1 x RJ9 (4P4C) handset port
> 1 x RJ9 (4P4C) headset port

Other Physical Features

> Wall mountable
> External Yealink AC adapter:

AC 100~240V input and DC 5V/600mA output > Power consumption (PSU): 0.8-1.4W
> Power consumption (PoE): 1.3-1.8W (T21P E2) > Dimension (W*D*H*T):

209 mm*188 mm*150 mm*41 mm
> Operating humidity: 10~95%
> Operating temperature: -10~50°C (+14~122°F)

Management

> Configuration: browser/phone/auto-provision > Auto provision via FTP/TFTP/HTTP/HTTPS

for mass deploy
> Auto-provision with PnP
> Zero-sp-touch, TR-069
> Phone lock for personal privacy protection > Reset to factory, reboot
> Package tracing export, system log

Network and Security

> SIP v1 (RFC2543), v2 (RFC3261)
> Call server redundancy supported
> NAT traversal: STUN mode
> Proxy mode and peer-to-peer SIP link mode > IP assignment: static/DHCP
> HTTP/HTTPS web server
> Time and date synchronization using SNTP > UDP/TCP/DNS-SRV (RFC 3263)
> QoS: 802.1p/Q tagging (VLAN), Layer 3 ToS

DSCP
> SRTP for voice
> Transport Layer Security (TLS)
> HTTPS certificate manager
> AES encryption for configuration file
> Digest authentication using MD5/MD5-sess > OpenVPN, IEEE802.1X
> IPv6
> LLDP/CDP/DHCP VLAN
> ICE

Package Features

> Package content:
– Yealink SIP-T21(P) E2 IP phone
– Handset with handset cord
– Ethernet Cable (1.5m CAT5E UTP Cable) – Stand
– Quick Start Guide