Yealink SIP-T4X Service manual

Copyright © 2014 YEALINK NETWORK TECHNOLOGY
Copyright © 2014 Yealink Network Technology CO., LTD. All rights reserved. No parts of this
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THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS GUIDE ARE
SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS, INFORMATION, AND
RECOMMENDATIONS IN THIS GUIDE ARE BELIEVED TO BE ACCURATE AND PRESENTED
WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. USERS MUST TAKE FULL
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CO., LTD. shall not be liable for errors contained herein nor for incidental or consequential
damages in connection with the furnishing, performance, or use of this guide.
Hereby, Yealink Network Technology CO., LTD. declares that this phone is in conformity
with the essential requirements and other relevant provisions of the CE, FCC.
This device is marked with the CE mark in compliance with EC Directives 2006/95/EC and 2004/108/EC.
This device is compliant with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including interference that may cause undesired
operation.

Note: This device is tested and complies with the limits for a Class B digital device, pursuant to Part 15 of the
FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television reception, which can be determined
by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more
of the following measures:
1. Reorient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
4. Consult the dealer or an experience radio/TV technician for help.
To avoid the potential effects on the environment and human health as a result of the
presence of hazardous substances in electrical and electronic equipment, end users of
electrical and electronic equipment should understand the meaning of the crossed-out
wheeled bin symbol. Do not dispose of WEEE as unsorted municipal waste and have to
collect such WEEE separately.
We are striving to improve our documentation quality and we appreciate your feedback. Email
your opinions and comments to [e-mail].

Yealink SIP-T4X IP phone firmware contains third-party software under the GNU General Public License
(GPL). Yealink uses software under the specific terms of the GPL. Please refer to the GPL for the exact terms
and conditions of the license.
The original GPL license, source code of components licensed under GPL and used in Yealink products can
be downloaded online:
http://www.yealink.com/GPLOpenSource.aspx?BaseInfoCateId=293&NewsCateId=293&CateId=293.

About This Guide
v
The guide is intended for administrators who need to properly configure, customize,
manage, and troubleshoot the IP phone system rather than the end-users. It provides
details on the functionality and configuration of SIP-T4X IP phones.
Many of the features described in this guide involve network settings, which could affect
the IP phone’s performance in the network. So an understanding of the IP networking
and prior knowledge of IP telephony concepts are necessary.
This guide covers SIP-T48G, T46G, T42G and T41P IP phones. The following related
documents for SIP-T4X IP phones are available:
Quick Installation Guides, which describe how to assemble IP phones.
Quick Reference Guides, which describe the most basic features available on IP
phones.
User Guides, which describe basic and advanced features available on IP phones.
Auto Provisioning Deployment Guide, which describes how to provision IP phones
using the configuration files.
Configuration Conversion Tool User Guide, which describes how to convert and
encrypt the configuration files using the Configuration Conversion Tool.
<y0000000000xx>.cfg and <MAC>.cfg template configuration files.
IP Phones Deployment Guide for BroadSoft UC-One Environments, which describes
how to configure the BroadSoft features on the BroadWorks web portal and IP
phones.
For support or service, please contact your Yealink reseller or go to Yealink Technical
Support online: http://www.yealink.com/Support.aspx.
The information detailed in this guide is applicable to the firmware version 72 or higher.
The firmware format is like x.x.x.x.rom. The second x from left should be greater than or
equal to 72 (e.g., the firmware version of SIP-T46G IP phone: 28.72.0.1.rom). This
administrator guide includes the following chapters:
Chapter 1, ―Product Overview‖describes SIP components and SIP IP phones.
Chapter 2, ―Getting Started‖describes how to install and connect IP phones and
configuration methods.

Administrator’s Guide for SIP-T4X IP Phones
vi
Chapter 3, ―Configuring Basic Features‖describes how to configure basic features
on IP phones.
Chapter 4, ―Configuring Advanced Features‖describes how to configure
advanced features on IP phones.
Chapter 5, ―Configuring Audio Features‖describes how to configure audio features
on IP phones.
Chapter 6, ―Configuring Security Features‖describes how to configure security
features on IP phones.
Chapter 7, ―Upgrading Firmware‖describes how to upgrade the firmware of IP
phones.
Chapter 8, ―Resource Files‖describes the resource files that can be downloaded
by IP phones.
Chapter 9, ―Troubleshooting‖describes how to troubleshoot IP phones and
provides some common troubleshooting solutions.
Chapter 10, ―Appendix‖provides the glossary, reference information about IP
phones compliant with RFC 3261, SIP call flows and sample configuration files.
This section describes the changes to this guide for each release and guide version.
This version is updated to incorporate SIP-T48G IP phones as one of the T4X device
models. The following sections are new for this version:
Directory on page 63
Search Source List in Dialing on page 64
Major updates have occurred to the following section:
SIP IP Phone Models on page 3
Connecting the IP Phone on page 9
Reading Icons on page 16
PPPoE on page 24
Wallpaper on page 39
Phone Lock on page 45
Language on page 52
Logo Customization on page 55
Distinctive Ring Tones on page 130

About This Guide
vii
Busy Lamp Field on page 141
Automatic Call Distribution on page 147
Directory Template on page 229
Super Search Template on page 230
The following sections are new for this version:
Power Indicator LED on page 36
Contrast on page 38
Major updates have occurred to the following sections:
DHCP on page 18
Backlight on page 41
Time and Date on page 47
Key as Send on page 60
Anonymous Call on page 79
Busy Lamp Field on page 141
Action URL on page 160
IPv6 Support on page 192
Transport Layer Security on page 209
Major updates have occurred to the following section:
Language on page 52
Major updates have occurred to the following sections:
Language on page 52
Anonymous Call on page 79
Major updates have occurred to the following sections:
Backlight on page 41

Administrator’s Guide for SIP-T4X IP Phones
viii
Language on page 52
Logo Customization on page 55
Anonymous Call on page 79
Action URL on page 160
Action URI on page 163
Audio Codecs on page 199
Major updates have occurred to the following sections:
Language on page 52
Auto Answer on page 75
Audio Codecs on page 199
Encrypting Configuration Files on page 217
This version is updated to incorporate T41P as one of the T4X device models. The
following section is new for this version:
Logo Customization on page 55
Major updates have occurred to the following sections:
SIP IP Phone Models on page 3
Configuring Transmission Methods of the Internet Port and PC Port on page 25
Language on page 52
Remote Phone Book on page 136
Server Redundancy on page 166
Audio Codecs on page 199
Transport Layer Security on page 209
Secure Real-Time Transport Protocol on page 215
This version is updated to incorporate T42G as one of the T4X device models. The
following section is new for this version:
SIP IP Phone Models on page 3

About This Guide
ix
Major updates have occurred to the following sections:
Reading Icons on page 16
PPPoE on page 24
Backlight on page 41
Language on page 52
Call Completion on page 77
TR-069 Device Management on page 190
IPv6 Support on page 192
Audio Codecs on page 199
Upgrading Firmware on page 221
Configuring DSS Key on page 387

Administrator’s Guide for SIP-T4X IP Phones
x

Table of Contents
xi
About This Guide...................................................................v
Documentations...............................................................................................................................v
In This Guide ....................................................................................................................................v
Summary of Changes .................................................................................................................... vi
Changes for Release 72.0, Guide Version 72.2.....................................................................vi
Changes for Release 72.0, Guide Version 72.1.................................................................... vii
Changes for Release 71.0, Guide Version 71.181................................................................ vii
Changes for Release 71.0, Guide Version 71.180................................................................ vii
Changes for Release 71.0, Guide Version 71.171................................................................ vii
Changes for Release 71.0, Guide Version 71.170............................................................... viii
Changes for Release 71.0, Guide Version 71.150............................................................... viii
Changes for Release 71.0, Guide Version 71.80................................................................. viii
Table of Contents .................................................................xi
Product Overview..................................................................1
VoIP Principle....................................................................................................................................1
SIP Components...............................................................................................................................2
SIP IP Phone Models........................................................................................................................3
Physical Features of SIP-T4X IP Phones ...................................................................................4
Key Features of SIP-T4X IP Phones...........................................................................................7
Getting Started .....................................................................9
Connecting the IP Phone.................................................................................................................9
Initialization Process Overview ....................................................................................................12
Verifying Startup ............................................................................................................................14
Configuration Methods.................................................................................................................14
Phone User Interface..............................................................................................................14
Web User Interface ................................................................................................................14
Configuration Files..................................................................................................................15
Reading Icons ................................................................................................................................16
Configuring Basic Network Parameters ......................................................................................18
DHCP .......................................................................................................................................18
Configuring Network Parameters Manually ........................................................................21
PPPoE........................................................................................................................................24
Configuring Transmission Methods of the Internet Port and PC Port .................................25

Administrator’s Guide for SIP-T4X IP Phones
xii
Creating Dial Plan..........................................................................................................................28
Replace Rule ...........................................................................................................................29
Dial-now ..................................................................................................................................30
Area Code...............................................................................................................................32
Block Out .................................................................................................................................33
Configuring Basic Features..................................................35
Power Indicator LED.......................................................................................................................36
Contrast ..........................................................................................................................................38
Wallpaper.......................................................................................................................................39
Backlight.........................................................................................................................................41
User Password................................................................................................................................42
Administrator Password ................................................................................................................43
Phone Lock .....................................................................................................................................45
Time and Date ...............................................................................................................................47
Language .......................................................................................................................................52
Loading Language Packs ......................................................................................................53
Specifying the Language to Use...........................................................................................54
Logo Customization .......................................................................................................................55
Softkey Layout................................................................................................................................56
Key as Send ...................................................................................................................................60
Hotline ............................................................................................................................................62
Directory .........................................................................................................................................63
Search Source List in Dialing ........................................................................................................64
Call Log...........................................................................................................................................66
Missed Call Log .............................................................................................................................67
Local Directory ...............................................................................................................................68
Live Dialpad...................................................................................................................................71
Call Waiting....................................................................................................................................72
Auto Redial .....................................................................................................................................74
Auto Answer...................................................................................................................................75
Call Completion.............................................................................................................................77
Anonymous Call.............................................................................................................................79
Anonymous Call Rejection ............................................................................................................80
Do Not Disturb................................................................................................................................82
Busy Tone Delay.............................................................................................................................86
Return Code When Refuse ............................................................................................................87
Early Media....................................................................................................................................88
180 Ring Workaround ....................................................................................................................89
Use Outbound Proxy in Dialog.....................................................................................................90
SIP Session Timer ...........................................................................................................................91
Session Timer .................................................................................................................................92
Call Hold.........................................................................................................................................93
Call Forward ..................................................................................................................................95

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xiii
Call Transfer .................................................................................................................................101
Network Conference ...................................................................................................................103
Transfer on Conference Hang Up ..............................................................................................104
Directed Call Pickup ....................................................................................................................105
Group Call Pickup........................................................................................................................108
Dialog-Info Call Pickup................................................................................................................111
Call Return ....................................................................................................................................113
Call Park........................................................................................................................................114
Web Server Type..........................................................................................................................115
Calling Line Identification Presentation.....................................................................................117
Connected Line Identification Presentation ..............................................................................118
DTMF.............................................................................................................................................119
Suppress DTMF Display ..............................................................................................................122
Transfer via DTMF........................................................................................................................123
Intercom........................................................................................................................................124
Outgoing Intercom Calls......................................................................................................124
Incoming Intercom Calls ......................................................................................................125
Configuring Advanced Features........................................129
Distinctive Ring Tones ..................................................................................................................130
Tones .............................................................................................................................................134
Remote Phone Book ....................................................................................................................136
LDAP..............................................................................................................................................138
Busy Lamp Field...........................................................................................................................141
Music on Hold ..............................................................................................................................145
Automatic Call Distribution .........................................................................................................147
Message Waiting Indicator ........................................................................................................149
Multicast Paging ..........................................................................................................................151
Sending RTP Stream.............................................................................................................151
Receiving RTP Stream ..........................................................................................................153
Call Recording..............................................................................................................................155
Hot Desking..................................................................................................................................159
Action URL ....................................................................................................................................160
Action URI .....................................................................................................................................163
Server Redundancy.....................................................................................................................166
SIP Server Domain Name Resolution..................................................................................168
LLDP...............................................................................................................................................171
VLAN .............................................................................................................................................174
VPN................................................................................................................................................178
Quality of Service ........................................................................................................................180
Network Address Translation .....................................................................................................183
802.1X Authentication..................................................................................................................185
TR-069 Device Management ......................................................................................................190
IPv6 Support .................................................................................................................................192

Administrator’s Guide for SIP-T4X IP Phones
xiv
Configuring Audio Features............................................... 197
Headset Prior ...............................................................................................................................197
Dual Headset...............................................................................................................................198
Audio Codecs ..............................................................................................................................199
Acoustic Clarity Technology........................................................................................................203
Acoustic Echo Cancellation .................................................................................................203
Voice Activity Detection .......................................................................................................204
Comfort Noise Generation ..................................................................................................205
Jitter Buffer ............................................................................................................................206
Configuring Security Features............................................ 209
Transport Layer Security..............................................................................................................209
Secure Real-Time Transport Protocol..........................................................................................215
Encrypting Configuration Files ...................................................................................................217
Upgrading Firmware......................................................... 221
Resource Files.................................................................... 225
Replace Rule Template ...............................................................................................................225
Dial-now Template.......................................................................................................................226
Softkey Layout Template.............................................................................................................227
Directory Template ......................................................................................................................229
Super Search Template...............................................................................................................230
Local Contact File ........................................................................................................................231
Remote XML Phone Book............................................................................................................233
Specifying the Access URL of Resource Files ............................................................................234
Troubleshooting................................................................. 237
Troubleshooting Methods ...........................................................................................................237
Viewing Log Files..................................................................................................................237
Capturing Packets ................................................................................................................240
Enabling the Watch Dog Feature........................................................................................240
Getting Information from Status Indicators........................................................................241
Analyzing Configuration Files..............................................................................................241
Troubleshooting Solutions ...........................................................................................................242
Why is the LCD screen blank?.............................................................................................242
Why doesn’t the IP phone get an IP address?...................................................................242
How do I find the basic information of the IP phone?.......................................................243
Why doesn’t the IP phone upgrade firmware successfully?.............................................243
Why doesn’t the IP phone display time and date correctly? ...........................................243

Table of Contents
xv
Why do I get poor sound quality during a call? ................................................................243
What is the difference between a remote phone book and a local phone book? .......244
What is the difference between user name, register name and display name? ..........244
How to reboot IP phone remotely?.....................................................................................244
How to increase or decrease the volume?........................................................................244
What will happen if I connect both PoE cable and power adapter? Which has the higher
priority?..................................................................................................................................245
What is auto provisioning? ..................................................................................................245
What is PnP? ..........................................................................................................................245
Why doesn’t the IP phone update the configuration?.......................................................245
What do ―on code‖and ―off code‖mean?........................................................................245
How to solve the IP conflict problem? ................................................................................246
How to reset your phone to factory configurations?.........................................................246
How to restore the administrator password? ....................................................................247
Appendix .......................................................................... 249
Appendix A: Glossary.................................................................................................................249
Appendix B: Time Zones.............................................................................................................251
Appendix C: Configuration Parameters ....................................................................................254
Setting Parameters in Configuration Files..........................................................................254
Basic and Advanced Feature Parameters.........................................................................254
Audio Feature Parameters...................................................................................................365
Upgrading Firmware............................................................................................................377
Resource Files .......................................................................................................................380
Troubleshooting ....................................................................................................................385
Configuring DSS Key ............................................................................................................387
Appendix D: SIP (Session Initiation Protocol)............................................................................403
RFC and Internet Draft Support ..........................................................................................403
SIP Request............................................................................................................................406
SIP Header ............................................................................................................................406
SIP Responses .......................................................................................................................408
SIP Session Description Protocol (SDP) Usage ..................................................................410
Appendix E: SIP Call Flows .........................................................................................................411
Successful Call Setup and Disconnect ...............................................................................412
Unsuccessful Call Setup—Called User is Busy ..................................................................414
Unsuccessful Call Setup—Called User Does Not Answer ................................................417
Successful Call Setup and Call Hold ..................................................................................419
Successful Call Setup and Call Waiting .............................................................................421
Call Transfer without Consultation ......................................................................................426
Call Transfer with Consultation............................................................................................430
Always Call Forward............................................................................................................435
Busy Call Forward ................................................................................................................439
No Answer Call Forward .....................................................................................................442
Call Conference....................................................................................................................445

Administrator’s Guide for SIP-T4X IP Phones
xvi
Appendix F: Sample Configuration File ....................................................................................450
Index................................................................................. 457

Product Overview
1
This chapter contains the following information about SIP-T4X IP phones:
VoIP Principle
SIP Components
SIP IP Phone Models
VoIP
VoIP (Voice over Internet Protocol) is a technology using the Internet Protocol instead of
traditional Public Switch Telephone Network (PSTN) technology for voice
communications.
It is a family of technologies, methodologies, communication protocols, and
transmission techniques for the delivery of voice communications and multimedia
sessions over IP networks. The H.323 and Session Initiation Protocol (SIP) are two
popular VoIP protocols that are found in widespread implementation.
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector
(ITU-T) that defines the protocols to provide audio-visual communication sessions on
any packet network. The H.323 standard addresses call signaling and control,
multimedia transport and control, and bandwidth control for point-to-point and
multi-point conferences.
It is widely implemented by voice and video conference equipment manufacturers, is
used within various Internet real-time applications such as GnuGK and NetMeeting and
is widely deployed by service providers and enterprises for both voice and video
services over IP networks.
SIP
SIP (Session Initiation Protocol) is the Internet Engineering Task Force’s (IETF’s) standard
for multimedia conferencing over IP. It is an ASCII-based, application-layer control
protocol (defined in RFC 3261) that can be used to establish, maintain, and terminate
calls between two or more endpoints. Like other VoIP protocols, SIP is designed to
address the functions of signaling and session management within a packet telephony
network. Signaling allows call information to be carried across network boundaries.
Session management provides the ability to control the attributes of an end-to-end call.

Administrator’s Guide for SIP-T4X IP Phones
2
SIP provides capabilities to:
Determine the location of the target endpoint -- SIP supports address resolution,
name mapping, and call redirection.
Determine the media capabilities of the target endpoint -- Via Session Description
Protocol (SDP), SIP determines the ―lowest level‖ of common services between
endpoints. Conferences are established using only the media capabilities that can
be supported by all endpoints.
Determine the availability of the target endpoint -- A call cannot be completed
because the target endpoint is unavailable. SIP determines whether the called
party is already on the IP phone or does not answer in the allotted number of rings.
It then returns a message indicating why the target endpoint is unavailable.
Establish a session between the origin and target endpoint -- The call can be
completed, SIP establishes a session between endpoints. SIP also supports mid-call
changes, such as the addition of another endpoint to the conference or the change
of a media characteristic or codec.
Handle the transfer and termination of calls -- SIP supports the transfer of calls from
one endpoint to another. During a call transfer, SIP simply establishes a session
between the transferee and a new endpoint (specified by the transferring party)
and terminates the session between the transferee and the transferring party. At
the end of a call, SIP terminates the sessions between all parties.
SIP is a peer-to-peer protocol. The peers in a session are called User Agents (UAs). A
user agent can function as one of the following roles:
User Agent Client (UAC) -- A client application that initiates the SIP request.
User Agent Server (UAS) -- A server application that contacts the user when a SIP
request is received and that returns a response on behalf of the user.
User Agent Client (UAC)
The UAC is an application that initiates up to six feasible SIP requests to the UAS. The six
requests issued by the UAC are: INVITE, ACK, OPTIONS, BYE, CANCEL and REGISTER.
When the SIP session is being initiated by the UAC SIP component, the UAC determines
the information essential for the request, which is the protocol, the port and the IP
address of the UAS to which the request is being sent. This information can be dynamic
and will make it challenging to put through a firewall. For this reason, it may be
recommended to open the specific application type on the firewall. The UAC is also
capable of using the information in the request URI to establish the course of the SIP
request to its destination, as the request URI always specifies the host which is essential.
The port and protocol are not always specified by the request URI. Thus if the request
does not specify a port or protocol, a default port or protocol is contacted. It may be

Product Overview
3
preferential to use this method when not using an application layer firewall. Application
layer firewalls like to know what applications are flowing though which ports and it is
possible to use content types of other applications other than the one you are trying to
let through what has been denied.
User agent server (UAS)
UAS is a server that hosts the application responsible for receiving the SIP requests from
a UAC, and on reception it returns a response to the request back to the UAC. The UAS
may issue multiple responses to the UAC, not necessarily a single response.
Communication between UAC and UAS is client/server and peer-to–peer.
Typically, a SIP endpoint is capable of functioning as both a UAC and a UAS, but it
functions only as one or the other per transaction. Whether the endpoint functions as a
UAC or a UAS depends on the UA that initiates the request.
This section introduces the SIP-T4X IP phone family. SIP-T4X IP phones are endpoints in
the overall network topology, which are designed to interoperate with other compatible
equipments including application servers, media servers, internet-working gateways,
voice bridges, and other endpoints. SIP-T4X IP phones are characterized by a large
number of functions, which simplify business communication with a high standard of
security and can work seamlessly with a large number of SIP PBXs.
SIP-T4X IP phones provide a powerful and flexible IP communication solution for Ethernet
TCP/IP networks, delivering excellent voice quality. The high-resolution graphic display
provides content in multiple languages for system status, call log and directory access.
SIP-T4X IP phones also support advanced functionalities, including LDAP, Busy Lamp
Field, Sever Redundancy and Network Conference.
The following IP phone models are described:
SIP-T48G
SIP-T46G
SIP-T42G
SIP-T41P
SIP-T4X IP phones comply with the SIP standard (RFC 3261), and they can only be used
within a network that supports this type of phone.
In order to operate as SIP endpoints in your network successfully, SIP-T4X IP phones must
meet the following requirements:
A working IP network is established.
Routers are configured for VoIP.
VoIP gateways are configured for SIP.

Administrator’s Guide for SIP-T4X IP Phones
4
The latest (or compatible) firmware of SIP-T4X IP phones is available.
A call server is active and configured to receive and send SIP messages.
This section lists the available physical features of SIP-T4X IP phones.
SIP-T48G
Physical Features:
-7‖ 800 x 480 pixel color touch screen with backlight
-24 bit depth color
-6 VoIP accounts, BroadSoft/Avaya/Asterisk validated
-HD Voice: HD Codec, HD Handset, HD Speaker
-27 keys including 7 feature keys
-1xRJ9 (4P4C) handset port
-1xRJ9 (4P4C) headset port
-2xRJ45 10/100/1000Mbps Ethernet ports
-1XRJ12 (6P6C) expansion module port
-4 LEDs: 1xpower, 1xmute, 1xheadset, 1xspeakerphone
-Power adapter: AC 100~240V input and DC 5V/2A output
-Power over Ethernet (IEEE 802.3af)
-Built-in USB port, support Bluetooth headset