Điện thoại IP Yealink T21P

Phone Features
2 VoIP accounts, hotline, emergency call
Call waiting, call transfer, call forward
Hold, mute, flash, auto-answer, redial
3-way conference, DND, speed dial
Phonebook import/export, call history
Volume adjustment, ring tone selection
Tone scheme, System log
Multi-language (more than 20)

IP PBX System Integration
Dial plan, dial-now
Voicemail, MWI
Intercom, Paging
Call park, call pickup
Distinctive ringtone

Codecs and Voice Features
Wideband codec: G.722
Narrowband codec: G.711, G.723.1, G.726, G.729AB
VAD, CNG, AEC, PLC, AJB, AGC
Full-duplex hands-free speakerphone with AEC

Network Features
SIP v1 (RFC2543), v2 (RFC3261)
NAT Traversal: STUN mode
DTMF: In-Band, RFC2833, SIP Info
Proxy mode and peer-to-peer SIP link mode
IP Assignment: Static/DHCP/PPPoE
TFTP/DHCP/PPPoE client
Telnet/HTTP/HTTPS server
DNS client
NAT/DHCP server

Management
FTP/TFTP/HTTP/PnP auto-provision
Configuration: browser/phone/auto-provision
Direct IP call without SIP proxy
Dial number via SIP server
Dial URL via SIP server

Security
HTTPS (server/client)
SRTP (RFC3711) 
Transport Layer Security (TLS)
VLAN (802.1 pq), QoS
Digest authentication using MD5/MD5-sess
Secure configuration file via AES encryption
Phone lock for personal privacy protection
Admin/user configuration mode

Physical Features
TI TITAN chipset
3-line LCD with an icon line and 2×15 characters lines
31 keys including 9 function keys
4 LEDs: 1xpower, 2xline, 1xmessage
1xRJ9 handset port
1xRJ9 headset port
2xRJ45 10/100M Ethernet ports
Wall-mounted
Power adapter: AC 100~240V input and DC 5V/1.2A Output
Power over Ethernet (IEEE 802.3af)
Power consumption: 1.4-2.6W
Net weight: 0.77kg
Dimension: 185 x 200 x 90mm
Operating humidity: 10~95%
Storage temperature: up to 60°C