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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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.
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
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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 Start Guides, which describe how to assemble IP phones and configure 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 73 or higher.
The firmware format is like x.x.x.x.rom. The second x from left should be greater than or
equal to 73 (e.g., the firmware version of SIP-T46G IP phone: [phone].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.
Chapter 3, “Configuring Basic Features”describes how to configure basic features

Administrator’s Guide for SIP-T4X IP Phones
vi
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 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.
The following section is new for this version:
Hide Features Access Code on page 303
Major updates have occurred to the following sections:
Physical Features of SIP-T4X IP Phones on page 4
Configuration Files on page 17
ReCall on page 232
Distinctive Ring Tones on page 260
BLF List on page 297
Static DNS Cache on page 371
Voice Quality Monitoring on page 426
Appendix C: Configuring DSS Key on page 514
Appendix B: Time Zones on page 511
The following sections are new for this version:
Notification Popups on page 52

About This Guide
vii
Call Display on page 62
Input Method Customization on page 99
Off Hook Hot Line Dialing on page 129
Feature Key Synchronization on page 211
BLF List on page 297
Capturing the Current Screen of the Phone on page 358
Voice Quality Monitoring on page 426
Major updates have occurred to the following sections:
Configuration Files on page 17
DHCP on page 21
Configuring Basic Network Parameters on page 21
Upgrading Firmware on page 40
Phone Lock on page 72
Language on page 90
Anonymous Call Rejection on page 158
DTMF on page 241
Distinctive Ring Tones on page 260
Remote Phone Book on page 273
LDAP on page 277
Message Waiting Indicator on page 310
Multicast Paging on page 316
VLAN on page 383
802.1X Authentication on page 399
IPv6 Support on page 414
Transport Layer Security on page 461
Secure Real-Time Transport Protocol on page 471
Encrypting Configuration Files on page 474
Analyzing Configuration Files on page 506
The following sections are new for this version:
Provisioning Server on page 18
Static DNS Cache on page 371
Background Noise Suppression on page 454

Administrator’s Guide for SIP-T4X IP Phones
viii
Automatic Gain Control on page 454
Major updates have occurred to the following section:
Configuration Methods on page 16
Call Hold on page 181
Audio Codecs on page 445
Acoustic Clarity Technology on page 452
Resource Files on page 481
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 131
Search Source List in Dialing on page 133
Major updates have occurred to the following section:
SIP IP Phone Models on page 3
Connecting the IP Phones on page 9
Reading Icons on page 14
PPPoE on page 32
Wallpaper on page 56
Phone Lock on page 72
Language on page 90
Logo Customization on page 103
Distinctive Ring Tones on page 260
Busy Lamp Field on page 289
Automatic Call Distribution on page 305
Directory Template on page 485
Super Search Template on page 486
The following sections are new for this version:
Power Indicator LED on page 48
Contrast on page 55
Major updates have occurred to the following sections:

About This Guide
ix
DHCP on page 21
Backlight on page 59
Time and Date on page 78
Key as Send on page 111
Anonymous Call on page 154
Busy Lamp Field on page 289
Action URL on page 337
IPv6 Support on page 414
Transport Layer Security on page 461
Major updates have occurred to the following section:
Language on page 90
Major updates have occurred to the following sections:
Language on page 90
Anonymous Call on page 154
Major updates have occurred to the following sections:
Backlight on page 59
Language on page 90
Logo Customization on page 103
Anonymous Call on page 154
Action URL on page 337
Action URI on page 354
Audio Codecs on page 445
Major updates have occurred to the following sections:
Language on page 90

Administrator’s Guide for SIP-T4X IP Phones
x
Auto Answer on page 149
Audio Codecs on page 445
Encrypting Configuration Files on page 474
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 103
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 35
Language on page 90
Remote Phone Book on page 273
Server Redundancy on page 359
Audio Codecs on page 445
Transport Layer Security on page 461
Secure Real-Time Transport Protocol on page 471
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
Major updates have occurred to the following sections:
Reading Icons on page 14
PPPoE on page 32
Upgrading Firmware on page 40
Backlight on page 59
Language on page 90
Call Completion on page 152
TR-069 Device Management on page 409
IPv6 Support on page 414
Audio Codecs on page 445
Appendix C: Configuring DSS Key on page 514

Table of Contents
xi
About This Guide ...................................................................... v
Documentations...............................................................................................................................v
In This Guide ....................................................................................................................................v
Summary of Changes .................................................................................................................... vi
Changes for Release 73, Guide Version 73.40...................................................................... vi
Changes for Release 73, Guide Version 73.16...................................................................... vi
Changes for Release 72.0, Guide Version 72.3.................................................................... vii
Changes for Release 72.0, Guide Version 72.2................................................................... viii
Changes for Release 72.0, Guide Version 72.1................................................................... viii
Changes for Release 71.0, Guide Version 71.181................................................................. ix
Changes for Release 71.0, Guide Version 71.180................................................................. ix
Changes for Release 71.0, Guide Version 71.171................................................................. ix
Changes for Release 71.0, Guide Version 71.170................................................................. ix
Changes for Release 71.0, Guide Version 71.150..................................................................x
Changes for Release 71.0, Guide Version 71.80.................................................................... x
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 Phones ...............................................................................................................9
Initialization Process Overview ....................................................................................................12
Verifying Startup ............................................................................................................................14
Reading Icons ................................................................................................................................14
Configuration Methods.................................................................................................................16
Phone User Interface..............................................................................................................16
Web User Interface ................................................................................................................17
Configuration Files..................................................................................................................17
Provisioning Server........................................................................................................................18
Supported Provisioning Protocols .........................................................................................18

Administrator’s Guide for SIP-T4X IP Phones
xii
Setting up the Provisioning Server........................................................................................19
Deploying Phones from the Provisioning Server .................................................................19
Configuring Basic Network Parameters ......................................................................................21
DHCP .......................................................................................................................................21
Configuring Network Parameters Manually ........................................................................26
PPPoE .......................................................................................................................................32
Configuring Transmission Methods of the Internet Port and PC Port .................................35
Configuring PC Port ................................................................................................................38
Upgrading Firmware.....................................................................................................................40
Configuring Basic Features .................................................... 47
Power Indicator LED ......................................................................................................................48
Notification Popups........................................................................................................................52
Contrast ..........................................................................................................................................55
Wallpaper.......................................................................................................................................56
Backlight.........................................................................................................................................59
Call Display ....................................................................................................................................62
Web Server Type............................................................................................................................65
User Password ...............................................................................................................................68
Administrator Password ................................................................................................................70
Phone Lock .....................................................................................................................................72
Time and Date ...............................................................................................................................78
Language .......................................................................................................................................90
Loading Language Packs ......................................................................................................90
Specifying the Language to Use...........................................................................................97
Input Method Customization ........................................................................................................99
Logo Customization.....................................................................................................................103
Softkey Layout..............................................................................................................................105
Key as Send ................................................................................................................................. 111
Dial Plan........................................................................................................................................115
Replace Rule .........................................................................................................................116
Dial-now ................................................................................................................................119
Area Code.............................................................................................................................123
Block Out ...............................................................................................................................125
Hotline ..........................................................................................................................................127
Off Hook Hot Line Dialing...........................................................................................................129
Directory.......................................................................................................................................131
Search Source List in Dialing ...................................................................................................... 133
Call Log.........................................................................................................................................134
Missed Call Log ...........................................................................................................................136
Local Directory.............................................................................................................................137
Live Dialpad................................................................................................................................. 142
Call Waiting..................................................................................................................................144
Auto Redial...................................................................................................................................147

Table of Contents
xiii
Auto Answer.................................................................................................................................149
Call Completion...........................................................................................................................152
Anonymous Call........................................................................................................................... 154
Anonymous Call Rejection ..........................................................................................................158
Do Not Disturb..............................................................................................................................162
Busy Tone Delay...........................................................................................................................172
Return Code When Refuse ..........................................................................................................174
Early Media..................................................................................................................................175
180 Ring Workaround ..................................................................................................................175
Use Outbound Proxy in Dialog...................................................................................................177
SIP Session Timer .........................................................................................................................179
Call Hold.......................................................................................................................................181
Session Timer ...............................................................................................................................186
Call Forward ................................................................................................................................188
Call Transfer .................................................................................................................................206
Network Conference ...................................................................................................................209
Feature Key Synchronization......................................................................................................211
Transfer on Conference Hang Up ..............................................................................................213
Directed Call Pickup....................................................................................................................214
Group Call Pickup........................................................................................................................222
Dialog-Info Call Pickup................................................................................................................229
ReCall............................................................................................................................................232
Call Park .......................................................................................................................................235
Calling Line Identification Presentation.....................................................................................238
Connected Line Identification Presentation ..............................................................................240
DTMF.............................................................................................................................................241
Suppress DTMF Display .............................................................................................................. 247
Transfer via DTMF ........................................................................................................................249
Intercom........................................................................................................................................250
Outgoing Intercom Calls......................................................................................................251
Incoming Intercom Calls ......................................................................................................254
Configuring Advanced Features...........................................259
Distinctive Ring Tones ..................................................................................................................260
Tones .............................................................................................................................................266
Remote Phone Book ....................................................................................................................273
LDAP..............................................................................................................................................277
Busy Lamp Field...........................................................................................................................289
BLF List .......................................................................................................................................... 297
Hide Features Access Code.......................................................................................................303
Automatic Call Distribution .........................................................................................................305
Message Waiting Indicator ........................................................................................................310
Multicast Paging ..........................................................................................................................316
Sending RTP Stream............................................................................................................. 316

Administrator’s Guide for SIP-T4X IP Phones
xiv
Receiving RTP Stream ..........................................................................................................324
Call Recording .............................................................................................................................328
Hot Desking..................................................................................................................................334
Action URL ....................................................................................................................................337
Action URI.....................................................................................................................................354
Capturing the Current Screen of the Phone.......................................................................358
Server Redundancy.....................................................................................................................359
SIP Server Domain Name Resolution..................................................................................367
Static DNS Cache ........................................................................................................................371
LLDP...............................................................................................................................................379
VLAN .............................................................................................................................................383
VPN................................................................................................................................................391
Quality of Service........................................................................................................................393
Network Address Translation .....................................................................................................397
802.1X Authentication .................................................................................................................399
TR-069 Device Management ......................................................................................................409
IPv6 Support ................................................................................................................................. 414
Configuring Audio Features ..................................................423
Headset Prior ...............................................................................................................................423
Dual Headset............................................................................................................................... 424
Voice Quality Monitoring ............................................................................................................426
RTCP-XR..................................................................................................................................426
VQ-RTCPXR............................................................................................................................ 427
Audio Codecs ..............................................................................................................................445
Acoustic Clarity Technology........................................................................................................452
Acoustic Echo Cancellation ................................................................................................. 452
Background Noise Suppression..........................................................................................454
Automatic Gain Control .......................................................................................................454
Voice Activity Detection .......................................................................................................454
Comfort Noise Generation ..................................................................................................455
Jitter Buffer ............................................................................................................................457
Configuring Security Features...............................................461
Transport Layer Security.............................................................................................................. 461
Secure Real-Time Transport Protocol..........................................................................................471
Encrypting Configuration Files ...................................................................................................474
Resource Files........................................................................481
Replace Rule Template ...............................................................................................................482
Dial-now Template.......................................................................................................................483
Softkey Layout Template.............................................................................................................484

Table of Contents
xv
Directory Template ......................................................................................................................485
Super Search Template...............................................................................................................486
Local Contact File ........................................................................................................................488
Remote XML Phone Book............................................................................................................490
Troubleshooting.....................................................................493
Troubleshooting Methods ...........................................................................................................493
Viewing Log Files..................................................................................................................493
Capturing Packets ................................................................................................................498
Enabling the Watch Dog Feature........................................................................................499
Getting Information from Status Indicators........................................................................501
Troubleshooting Solutions ...........................................................................................................501
Why is the LCD screen blank? .............................................................................................501
Why doesn’t the IP phone get an IP address?...................................................................501
How do I find the basic information of the IP phone?.......................................................502
Why doesn’t the IP phone upgrade firmware successfully?.............................................502
Why doesn’t the IP phone display time and date correctly? ...........................................502
Why do I get poor sound quality during a call? ................................................................502
What is the difference between a remote phone book and a local phone book? .......503
What is the difference between user name, register name and display name? ..........503
How to reboot the IP phone remotely? ..............................................................................503
Why does the IP phone use DOB format logo file instead of popular BMP, JPG and so on?
................................................................................................................................................503
How to increase or decrease the volume?........................................................................504
What will happen if I connect both PoE cable and power adapter? Which has the higher
priority?.................................................................................................................................. 504
What is auto provisioning? ..................................................................................................504
What is PnP? ..........................................................................................................................504
Why doesn’t the IP phone update the configuration? ......................................................504
What do “on code”and “off code”mean? .......................................................................505
How to solve the IP conflict problem? ................................................................................ 505
How to reset your phone to factory configurations?.........................................................505
How to restore the administrator password? ....................................................................506
Analyzing Configuration Files .............................................................................................506
Appendix ...............................................................................509
Appendix A: Glossary.................................................................................................................509
Appendix B: Time Zones.............................................................................................................511
Appendix C: Configuring DSS Key.............................................................................................514
Appendix D: SIP (Session Initiation Protocol)............................................................................ 523
RFC and Internet Draft Support ..........................................................................................523
SIP Request............................................................................................................................526
SIP Header ............................................................................................................................527

Administrator’s Guide for SIP-T4X IP Phones
xvi
SIP Responses .......................................................................................................................528
SIP Session Description Protocol (SDP) Usage ..................................................................530
Appendix E: SIP Call Flows......................................................................................................... 531
Successful Call Setup and Disconnect ...............................................................................531
Unsuccessful Call Setup—Called User is Busy ..................................................................534
Unsuccessful Call Setup—Called User Does Not Answer ................................................536
Successful Call Setup and Call Hold..................................................................................538
Successful Call Setup and Call Waiting .............................................................................541
Call Transfer without Consultation ......................................................................................546
Call Transfer with Consultation............................................................................................550
Always Call Forward............................................................................................................555
Busy Call Forward ................................................................................................................558
No Answer Call Forward .....................................................................................................561
Call Conference.................................................................................................................... 564
Index ......................................................................................569

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.
VoIP gateways are configured for SIP.
The latest (or compatible) firmware of SIP-T4X IP phones is available.

Administrator’s Guide for SIP-T4X IP Phones
4
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
-16 VoIP accounts, Broadsoft Validated/Asterisk®Compatible
-HD Voice: HD Codec, HD Handset, HD Speaker
-26 keys including 7 feature keys
-1*RJ9 (4P4C) handset port
-1*RJ9 (4P4C) headset port
-2*RJ45 10/100/1000Mbps Ethernet ports
-1*RJ12 (6P6C) expansion module port
-4 LEDs: 1*power, 1*mute, 1*headset, 1*speakerphone
-Power adapter: AC 100~240V input and DC 5V/2A output
-Power over Ethernet (IEEE 802.3af)
-Built-in USB port, support Bluetooth headset