Yealink SIP-T21

Yealink SIP-T21 is a new mid-range IP phone manufactured by Yealink. The SIP-T21 model is a logical continuation of the SIP-T20 model , has similar functionality, but is distinguished by higher performance and technical characteristics. The Yealink SIP-T21 IP phone supports two lines using the popular VoIP protocol SIP, and is also equipped with two Ethernet 10/100 Mbps ports that can operate as a switch or router. Thanks to this, as well as the presence of a high-quality LCD display and full Russification, setting up and working with the IP phone does not cause any difficulties at all.

Yealink SIP-T21 is a new mid-range IP phone manufactured by Yealink. The SIP-T21 model is a logical continuation of the SIP-T20 model , has similar functionality, but is distinguished by higher performance and technical characteristics. The Yealink SIP-T21 IP phone supports two lines using the common VoIP protocol SIP, providing the ability to configure them independently. The line for making a call is selected using two special backlit keys. The SIP-T21 model is also equipped with two Ethernet 10/100 Mbps ports, which can operate as a switch or router. Due to this, as well as the presence of a high-quality LCD display and full Russification, setting up and working with the IP phone does not cause any difficulties at all. The Yealink SIP-T21 IP phone supports absolutely all standard functions of modern telephony and at the same time has an extremely attractive price. This makes this phone suitable for use in both small offices and large companies.

Phone specifications

• Support for 2 SIP lines with independent configuration.
• 2 programmable buttons with light indication. Subscriber status display (BLF).
• Fully Russified: has a Russian menu, web interface, and contact entry in Russian.
• Keyboard with Russian alphabet.
• Phone book (1000 entries), phone book export/import, black list, call history (100 entries), speed and accelerated dialing, dialing rules.
• Keypad lock, volume control, ringtone selection.
• Call hold and waiting, call forwarding and transfer, DND mode, conference calling, call pickup, intercom calls (including group intercom call: Paging), hotline, auto answer, emergency call, auto redial mode.
• Voicemail.
• Manage and configure your IP phone from the keyboard, via the Web interface or remotely.
• Centralized installation, setup, configuration and software update via Autoprovision function (TFTP/FTP/HTTP/HTTPS/PNP/DHCP).
• Support for SNMP v1/2, TR069 protocol (optional).
• Support for Yealink RPS (Redirection and Provisioning Service).
• Special features for BroadSoft, Genesys, etc. platforms.

Network characteristics of the Yealink SIP-T21 IP phone

• Support for SIP 2.0 protocol (RFC3261).
• Transport: UDP, TCP, TLS, DNS SRV.
• NAT transverse support: STUN mode.
• Call modes: Peer-to-Peer, SIP Proxy.
• 3 network modes: DHCP/static IP/PPPoE.
• Support 802.1x, LLDP.
• Support VLAN (IEEE 802.1p/q tagging); TOS (layer 3).
• Supports in-band DTMF, out-of-band RFC2833 DTMF and SIP INFO.
• Support for encryption and identification standards (MD5 and MD5-sess).
• SRTP support.
• HTTPS client/server.

Working with voice in the Yealink SIP-T21 IP phone

• HD speakerphone and hands-free; HD codec G.722.
• Sound spectrum from 50Hz to 7kHz.
• Support for wideband codec G.722, support for standard codecs G.711, G.726, G.729AB, G.723.1.
• Supports VAD (Voice Activity Detection), CNG (Convenient Noise Generator), AEC (Echo Cancellation), NLP (Noise Suppression), AGC (Automatic Gain Control), AJB (Adaptive Jitter Buffer).
• High quality speakerphone with echo cancellation.

Physical characteristics of the Yealink SIP-T21 IP phone

• Two RJ45 ports (NAT and Bridge modes).
• Headset jack RJ9(4P4C).
• LCD: 132x64 pixels without screen backlight.
• DC 5V, 0.6A.
• Consumption: 1.4-2.6W.
• Possibility of wall mounting.
• Working temperature: 0°~40°.
• Dimensions: 188x150x41mm.
• Weight: 0.81kg.
• Colour: grey.