The Yealink SIP-T42S IP phone, combined with a hosted V2VIP™ Calling Plan, is a dynamic business communications tool for superior voice communications and extended functionality. It has a faster, more responsive interface than the T42G and offers better overall performance. The SIP-T42S is a 12-line IP phone with multiple programmable keys for enhancing productivity.—$109.99
Main Features
- Yealink Optima HD Voice
- Dual port Gigabit Ethernet
- Codecs: Opus, G.722, G.711 (A/u), G.723.1, G.729AB, G.726, iLBC
- Display: 2.7″ 192×64 pixel graphical LCD with backlight
- Up to 12 SIP accounts
- 6 Line keys with dual color LEDs can be programmed with up to 15 features (3 page view)
- 4 Soft Keys
- Paper label-free design
- One RJ9 headset port with EHS support (with EHS36 wireless headset adapter)
- Integrated stand with 2 adjustable angles
- Wall mountable with WMB-T4S kit
- PoE 802.3af, class 2
- Device performance enhancement with faster user interface response
- Opus support
- Enhanced speaker performance
- USB port for Bluetooth headset with BT40 dongle or WiFi support with WF40 dongle
- Hearing aid compatible handset
- No power supply included (Sold Separately)-$10.99

It features Yealink’s Optima HD Voice Technology and Opus wideband codec for superb sound quality and crystal clear communications. What’s more, the SIP-T42S is built with Gigabit Ethernet technology for rapid call handling. Plus, with an all-new USB port, the SIP-T42S boasts unparalleled functionality and expansibility, which comes ready for future Bluetooth, Wi-Fi and USB recording features. The new T4S series offers the same elegant appearance of the T4 line, but with improvements for greater interoperability and collaboration.
Audio Features
• HD voice: HD handset, HD speaker
• Hearing aid compatible (HAC) handset
• Wideband codec: Opus*, G.722
• Narrowband codec: Opus*, G.711(A/µ), G.723.1, 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
• 12 VoIP accounts
• One-touch speed dial, redial
• Call forward, call waiting
• Call transfer, call hold
• Call return, group listening
• Mute, auto answer, DND
• 3-way conference call
• Direct IP call without SIP proxy
• Ring tone selection/import/delete
• Hotline, emergency call
• Set date time manually or automatically
• Dial plan, XML Browser, Action URL/URI
• RTCP-XR (RFC3611), VQ-RTCPXR (RFC6035)
• USB port (2.0 compliant): Bluetooth earphone through BT40 (pending), Wi-Fi through WF40 (pending)
• Enhanced DSS key