Yealink Phone Manual T42S

The Yealink T42S is a feature-rich SIP desktop IP phone designed for business environments. It features a 4.3-inch color LCD display, HD voice quality, dual Gigabit Ethernet ports, PoE support, built-in Bluetooth, Wi-Fi capability (with optional module), support for up to 12 SIP accounts, and compatibility with major IP PBX platforms. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Advanced Features 8. Accessibility Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Color LCD display, Handset, Base unit, Ethernet ports, Power adapter, Mounting bracket.

Feature	Description
Display	4.3-inch color TFT LCD with 480x272 resolution
Network Ports	Dual Gigabit Ethernet (LAN/PoE & PC)
Audio	HD handset and speakerphone with wideband audio
Wireless	Built-in Bluetooth, optional Wi-Fi module
Accounts	Supports up to 12 SIP accounts
Codecs	G.722, G.711, G.729, G.726, iLBC, Opus
Headset Port	3.5mm headset jack for wired headsets
Expansion Module	Supports up to 2 Yealink expansion modules
Power	PoE (802.3af) or AC power adapter
Firmware	Upgradable via web interface or TFTP

Installation

Unpack and inspect contents. Place on stable surface or mount on wall.

Connect network: Use Ethernet cable to connect LAN/PoE port to network switch/router.
Connect PC (optional): Use second Ethernet cable from PC port to computer.
Power the phone: Use PoE from switch or connect AC power adapter.
Connect handset: Plug handset cord into dedicated port on base.
Connect headset (optional): Plug into 3.5mm headset jack.

WARNING! Use only Yealink-approved power adapter. Ensure proper ventilation around device.

First-Time Setup

Power on phone; follow on-screen prompts.

Network configuration: Phone will attempt DHCP. For static IP, configure via keypad or web interface.
Account registration: Enter SIP server details provided by your service provider.
Set language: Press Menu > Settings > Basic > Preferences > Language.
Date and time: Configure via NTP server or manual setting.
Audio adjustment: Test and adjust handset, speakerphone, and ringer volume.

CAUTION! Handle handset cord carefully to avoid damage to connectors.

Specifications

Display: 4.3-inch color TFT, 480x272 pixels.
Network: Dual 10/100/1000 Mbps Ethernet, IEEE 802.3af PoE.
Protocols: SIP (RFC3261), TCP/IP, UDP, RTP, RTCP, HTTP, HTTPS.
Audio Features: HD voice, full-duplex speakerphone, acoustic echo cancellation.
Wireless: Bluetooth 4.2, optional 802.11a/b/g/n Wi-Fi.
Physical: 235mm x 200mm x 75mm, 1.1kg.
Power Supply: 100-240V AC, 50/60Hz or PoE.
Operating Temp: 0°C to 40°C (32°F to 104°F).
Supported Platforms: BroadSoft, Asterisk, 3CX, Metaswitch, etc.

Controls and Settings

Access menu via dedicated Menu button. Front Panel: LCD, soft keys, navigation pad, volume keys, mute, headset, speakerphone.

Key Functions: Hold, Transfer, Conference, Redial, Message, Directory, Headset, Mute, Speakerphone, Volume up/down.

Basic Settings: Language, time format, date format, screen saver. Audio Settings: Handset volume, speaker volume, ringer volume, tone settings. Network Settings: DHCP/Static IP, VLAN, QoS. Account Settings: Display name, SIP server, authentication, codec priority.

Connecting Devices

Network: LAN/PoE port to network. PC: PC port to computer. Headset: 3.5mm jack. Expansion: DSS keys via EXP40 module.

Turn off phone before connecting additional devices.
Match cables to correct ports (Ethernet to LAN, handset to handset port).
For Bluetooth headset: Enable Bluetooth in menu and pair device.

Tip: Use Cat5e or higher Ethernet cables for Gigabit performance.

Advanced Features

Supports advanced PBX features and customization.

Call Features: Hold, transfer, forward, park, pickup, intercom.
Conference: 3-party conference call.
Call Recording: Automatic or manual via dedicated key.
BLF: Busy Lamp Field for monitoring extension status.
XML Browser: Custom directory and services via XML.
Hot Desking: Log in with account credentials on shared phone.
VPN Support: Connect securely to corporate network.
Firewall Traversal: STUN, TURN, ICE for NAT environments.

WARNING! Configure advanced features through administrator interface only.

Accessibility Features

High Contrast Display: Adjust in display settings. Audio Accessibility: Adjustable ringer patterns and volumes. Large Font: Option for larger text on display. TTY Support: Compatible with teletype devices.

Care & Cleaning

Unplug power before cleaning. Use slightly damp, lint-free cloth. Do not use abrasive cleaners or solvents.

CAUTION! Avoid liquid contact with openings. Keep away from extreme temperatures and humidity.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for residential use. CE, RCM, UKCA marked. Contains FCC ID: 2AJMTT42S. For EU: WEEE directive applies. Copyright © Yealink Network Technology Co., Ltd. For support, visit www.yealink.com or contact your local distributor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power source/connection	Check PoE switch or power adapter; ensure cable is secure.
No network connection	Cable/DHCP	Check Ethernet cable; verify DHCP server is active.
Cannot register	Account settings	Verify SIP server address, username, password; check network firewall.
No audio	Volume/mute	Check volume settings; ensure mute is off; verify codec compatibility.
Display issues	Settings/cable	Adjust contrast/brightness; check display cable connection internally.
Bluetooth not pairing	Distance/settings	Ensure device is in pairing mode and within range; enable Bluetooth on phone.

Reset: Press and hold OK key during boot for factory reset (erases all settings).

Service: Contact authorized Yealink service center or visit www.yealink.com/support