Yealink SIP T42S Manual

The Yealink SIP T42S is a feature-rich, high-definition IP phone designed for business environments. It supports wideband audio, dual Gigabit Ethernet ports, PoE (Power over Ethernet), a 4.3-inch color LCD with touch support, and extensive SIP compatibility. Below are key sections covering safety, features, installation, configuration, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting to Network 7. Basic Call Operations 8. Advanced Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: HD handset, color LCD screen, Ethernet ports, programmable keys, and base unit.

Feature	Description
HD Voice	Wideband audio for crystal-clear calls
Display	4.3-inch color TFT LCD with capacitive touch
Network Ports	Dual Gigabit Ethernet (LAN/PoE and PC)
Power Options	PoE (802.3af) or external power adapter
Programmable Keys	Up to 27 (including line keys and expansion modules)
Headset Port	3.5mm jack for headset connectivity
Supported Protocols	SIP, TLS, SRTP, IPv6
Conference	Built-in 3-way audio conference
Codecs	G.722, G.711, G.729, Opus
Firmware Upgrade	Via web interface or TFTP

Installation

Unpack and inspect contents. Place on stable, flat surface.

Connect to Network: Use Ethernet cable from router/switch to phone's LAN/PoE port.
Connect PC (optional): Use second Ethernet cable from phone's PC port to computer.
Power the Phone: Use PoE from switch or connect the included power adapter.
Connect Handset and Headset: Plug handset cord into designated port; optional headset into 3.5mm jack.

WARNING! Use only approved power adapter. Ensure cables are securely connected.

First-Time Setup

Power on phone; follow on-screen prompts.

Network Boot: Phone will attempt to obtain IP via DHCP.
Check IP Address: Press "OK" or navigate to Status > Network to view IP.
Access Web Interface: Enter phone's IP in a web browser to configure SIP accounts.
Configure SIP Account: Enter server address, username, password provided by your VoIP provider.
Apply Settings: Save and reboot phone for changes to take effect.

CAUTION! Handle phone with care; avoid exposure to liquids.

Specifications

Display: 4.3-inch TFT, 480 x 272 pixels, capacitive touch.
Network: Dual 10/100/1000 Mbps Ethernet, IEEE 802.3af PoE.
Audio: HD handset, built-in speakerphone, wideband codecs.
Programmable Keys: 6 line keys (expandable via EXP40 module).
Protocols: SIP RFC3261, TLS, SRTP, IPv4/IPv6.
Power Supply: Input: 100-240V AC, 50/60Hz; Output: 12V DC, 1.5A.
Operating Conditions: Temperature: 0°C to 40°C; Humidity: 10% to 90% non-condensing.
Dimensions: 235mm (W) x 195mm (D) x 175mm (H).

Controls and Settings

Access menu via touch screen or physical keys. Front Panel: LCD touch screen, navigation keys, volume keys, mute, headset, speakerphone.

Physical Keys: Hold, Transfer, Conference, Directory, Message, Mute, Volume up/down, Headset, Speakerphone.

Phone Settings: Via web interface or phone menu—Network (static/DHCP), SIP accounts, audio settings (ringer volume, codec priority), time & date, screen brightness. Programmable Keys: Assign functions like speed dial, BLF (Busy Lamp Field), call park.

Connecting to Network

LAN: Use Ethernet cable to router/switch. PC Pass-through: Connect computer to PC port for shared network access.

Ensure network switch/router is powered and operational.
Connect phone's LAN port to network using Cat5e or better cable.
Verify link LED is solid or blinking.
For PC connection, plug cable from PC port to computer's Ethernet port.

Tip: Use PoE switch to simplify installation and reduce cable clutter.

Basic Call Operations

Make, answer, end calls, hold, transfer, conference.

Make Call: Lift handset or press Speakerphone, dial number, press Dial softkey or #.
Answer Call: Lift handset, press Speakerphone, or press Answer softkey.
End Call: Press EndCall key or place handset back.
Hold: Press Hold key during active call.
Transfer: During call, press Transfer, dial target number, press Transfer again.
Conference: During first call, press Conference, dial second party, press Conference again to merge.
Mute: Press Mute key to toggle microphone on/off.
Adjust Volume: Use volume keys during call or idle for ringer volume.

WARNING! Do not disassemble phone; refer service to qualified personnel.

Advanced Features

Call Forwarding: Set via phone menu or web interface (always, busy, no answer). BLF (Busy Lamp Field): Monitor extension status on programmable keys. Call Recording: Initiate via dedicated key or softkey (if supported by server). Directory: Store contacts locally or access LDAP corporate directory. Expansion Modules: Add EXP40 module for additional programmable keys.

Care & Maintenance

Unplug power before cleaning. Use soft, dry cloth for screen and body; avoid abrasive cleaners.

CAUTION! Do not use liquids or sprays directly on phone. Keep away from heat sources and moisture.

Regulatory Information

FCC Part 15: Class B digital device; complies with limits for residential installation. CE, RCM, UKCA marked. This device complies with relevant RoHS directives. For support, visit www.yealink.com or contact your authorized reseller. Copyright © Yealink Inc. All rights reserved.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power source/cable	Check power adapter connection; verify PoE switch is enabled; try different cable.
No network connection	Cable/DHCP	Ensure Ethernet cable is securely plugged; check router/switch; verify DHCP is on.
No dial tone	SIP configuration	Verify SIP account settings (server, username, password); check network connectivity.
One-way/no audio	Network/Codec	Check firewall/NAT settings; ensure proper codec negotiation (try G.711).
Phone not registering	Server address/credentials	Confirm SIP server address and port; re-enter username and password; check for typos.

Reset: Press and hold OK key during boot for factory reset (use with caution).

Support: www.yealink.com; consult your system administrator or VoIP provider.