3Com VCX V7122 User manual

3Com®VCX™ V7122 VoIP SIP
Gateway User Manual
Version 4.4
http://www.3com.com
Part Number 900-0255-01
Published June 2005

3Com VCX V7122 SIP VoIP Gateway User Manual
2
3Com Corporation, 350 Campus Drive, Marlborough MA 01752-3064
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3Com VCX V7122 SIP VoIP Gateway User Manual 3
CONTENTS
ABOUT THIS GUIDE 9
How to Use This Guide 9
Conventions 10
Related Documentation 10
Documentation Comments 10
CHAPTER 1: VCX V7122 SIP OVERVIEW 13
Available Configurations 14
SIP Overview 15
VCX V7122 VoIP SIP Supported Features 15
General Features 15
Hardware Features 15
PSTN-to-SIP Interworking 16
Supported SIP Features 17
CHAPTER 2: VCX V7122 SIP PHYSICAL DESCRIPTION 19
General 19
The VCX V7122 Chassis 20
Power Supply 20
The TP-1610 Board 20
Board Hot-Swap Support 21
TP-1610 Front Panel LED Indicators 22
Rear Transition Module 23
Optional CPU Board 24
CHAPTER 3: INSTALLING THE VCX V7122 25
Unpacking 25
Package Contents 26
Mounting the VCX V7122 26
Mounting the VCX V7122 on a Desktop 26
Installing the VCX V7122 in a 19-inch Rack 26
Cabling the VCX V7122 28
Connecting the E1/T1 Trunk Interfaces 30
Installing the Ethernet Connection 31
Connecting the Power Supply 31
CHAPTER 4: GETTING STARTED 35

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Assigning the VCX V7122 IP Address 35
Assigning an IP Address Using HTTP 35
Assigning an IP Address Using BootP 36
Restoring Networking Parameters to Their Initial State 37
Configuring the VCX V7122 Basic Parameters 37
CHAPTER 5: WEB MANAGEMENT 41
Configuration Concepts 41
Overview of the Embedded Web Server 41
Computer Requirements 41
Password Control 42
Embedded Web Server Username and Password 42
Configuring the Web Interface via the ini File 42
Limiting the Embedded Web Server to Read-Only Mode 42
Disabling the Embedded Web Server 42
Accessing the Embedded Web Server 42
Using Internet Explorer to Access the Embedded Web Server 43
Getting Acquainted with the Web Interface 43
Main Menu Bar 44
Saving Changes 45
Entering Phone Numbers in Various Tables 45
Protocol Management 45
Protocol Definition Parameters 46
Advanced Parameters 47
Number Manipulation Tables 47
Configuring the Routing Tables 52
Configuring the Profile Definitions 58
Configuring the Trunk Group Table 62
Configuring the Trunk Group Settings 63
Advanced Configuration 65
Configuring the Network Settings 65
Configuring the Channel Settings 68
Configuring the Trunk Settings 69
Configuring the TDM Bus Settings 72
Restoring and Backing Up the Gateway Configuration 72
Regional Settings 73
Changing the VCX V7122 Username and Password 75
Status and Diagnostic 75
Gateway Statistics 75
Monitoring the VCX V7122 Trunks and Channels 77
Activating the Internal Syslog Viewer 79
System Information 80
Software Update Menu 81
Software Upgrade Wizard 81

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Auxiliary Files 86
Updating the Software Upgrade Key 88
Save Configuration 88
Resetting the VCX V7122 89
CHAPTER 6: INI FILE CONFIGURATION OF THE VCX V7122 91
Secured ini File 91
Modifying an ini File 91
The ini File Content 92
The ini File Structure 92
The ini File Structure Rules 92
The ini File Example 93
Basic, Logging, Web, and RADIUS Parameters 93
SNMP Parameters 101
SIP Configuration Parameters 102
ISDN and CAS Interworking-Related Parameters 114
Number Manipulation and Routing Parameters 119
E1/T1 Configuration Parameters 127
Channel Parameters 132
Dynamic Jitter Buffer Operation 136
Configuration Files Parameters 137
CHAPTER 7: CONFIGURATION FILES 139
Configuring the Call Progress Tones 139
Format of the Call Progress Tones Section in the ini File 139
Prerecorded Tones (PRT) File 141
PRT File Format 141
Voice Prompts File 142
CAS Protocol Configuration Files 142
CHAPTER 8: GATEWAY CAPABILITIES DESCRIPTION 143
Proxy or Registrar Registration Example 143
Redirect Number and Calling Name (Display) 143
ISDN Overlap Dialing 144
Using ISDN NFAS 144
NFAS Interface ID 145
Working with DMS-100 Switches 146
Configuring the DTMF Transport Types 146
Configuring the Gateway’s Alternative Routing (based on Connectivity and QoS) 150
Alternative Routing Mechanism 150
Determining the Availability of Destination IP Addresses 150
PSTN Fallback as a Special Case of Alternative Routing 150
Relevant Parameters 151
Working with Supplementary Services 151

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Call Hold and Retrieve Features 151
Call Transfer 151
TDM Tunneling 152
Implementation 152
Call Detail Report 154
Trunk to Trunk Routing Example 156
SIP Call Flow Example 157
SIP Authentication Example 160
CHAPTER 9: DIAGNOSTICS 163
VCX V7122 Self-Testing 163
Syslog Support 163
Syslog Servers 164
Operation 164
CHAPTER 10: BOOTP/DHCP SUPPORT 167
Startup Process 167
DHCP Support 169
BootP Support 169
Upgrading the VCX V7122 169
Vendor Specific Information Field 170
CHAPTER 11: SNMP-BASED MANAGEMENT 173
About SNMP 173
SNMP Message Standard 173
SNMP MIB Objects 174
SNMP Extensibility Feature 175
Carrier Grade Alarm System 175
Active Alarm Table 175
Alarm History 176
Cold Start Trap 176
Third-Party Performance Monitoring Measurements 176
Supported MIBs 177
SNMP Interface Details 180
SNMP Community Names 180
Trusted Managers 181
SNMP Ports 183
Multiple SNMP Trap Destinations 183
SNMP Manager Backward Compatibility 185
Element Management System 185
CHAPTER 12: SELECTED TECHNICAL SPECIFICATIONS 187
APPENDIX A: VCX V7122 SIP SOFTWARE KIT 191

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APPENDIX B: THE BOOTP/TFTP CONFIGURATION UTILITY 193
When to Use the BootP/TFTP 193
An Overview of BootP 193
Key Features 193
Specifications 194
Installation 194
Loading the cmp File, Booting the Device 194
BootP/TFTP Application User Interface 195
Function Buttons on the Main Screen 195
Log Window 196
Setting the Preferences 197
BootP Preferences 198
TFTP Preferences 198
Configuring the BootP Clients 199
Adding Clients 199
Deleting Clients 200
Editing Client Parameters 200
Testing the Client 201
Setting Client Parameters 201
Using Command Line Switches 202
Managing Client Templates 203
APPENDIX C: RTP/RTCP PAYLOAD TYPES AND PORT ALLOCATION 205
Payload Types Defined in RFC 1890 205
Defined Payload Types 205
Default RTP/RTCP/T.38 Port Allocation 206
APPENDIX D: FAX AND MODEM TRANSPORT MODES 209
Configuring Fax Relay Mode 209
Configuring Fax/Modem ByPass Mode 209
Supporting V.34 Faxes 210
APPENDIX E: VCX V7122 CLOCK SETTINGS 211
APPENDIX F: CUSTOMIZING THE VCX V7122 WEB INTERFACE 213
Replacing the Main Corporate Logo 213
Replacing the Main Corporate Logo with an Image File 214
Replacing the Main Corporate Logo with a Text String 215
Replacing the Background Image File 215
Customizing the Product Name 216
Modifying ini File Parameters via the Web AdminPage 217
APPENDIX G: ACCESSORY PROGRAMS AND TOOLS 219

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TrunkPack Downloadable Conversion Utility 219
Converting a CPT ini File to a Binary dat File 220
Creating a Loadable Voice Prompts File 221
Encoding/Decoding an ini File 223
Creating a Loadable Prerecorded Tones File 224
PSTN Trace Utility 226
Operation 226
APPENDIX H: SOFTWARE UPGRADE KEY 229
Loading the Software Upgrade Key 229
Loading the Software Upgrade Key Using the Embedded Web Server 229
Loading the Software Upgrade Key Using BootP/TFTP 231
Verifying That the Key was Successfully Loaded 231
Troubleshooting an Unsuccessful Loading of a Key 231
APPENDIX I: RELEASE REASON MAPPING 233
APPENDIX J: RADIUS BILLING AND CALLING CARD APPLICATION 237
Benefits 237
Features 237
Supported Architecture 238
Implementation 239
Basic Calling Card IVR Scenario 239
Call Flow Description 240
Operation and Configuration 241
Configuration Parameters 242
Supported RADIUS Attributes 243
RADIUS Server Messages 246
Authentication 246
Authorization 247
Accounting 247
Voice XML Interpreter 247
Features 248
Supported Elements and Attributes 249
Provided Calling Card System 255
Voice Prompts 255
VXML Flow Chart 257
VXML Script Example 261

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ABOUT THIS GUIDE
This User Manual describes the 3Com®VCX™V7122 Gateway.
This product is supported by software version 4.4, and enables you to send voice, fax, and
data over the same IP network.
Information contained in this document is believed to be accurate and reliable at the time of
printing. However, because of on-going product improvements and revisions, 3Com cannot
guarantee the accuracy of printed material after the Date Published nor can it accept
responsibility for errors or omissions. Updates to this document and other documents can be
viewed by registered Technical Support customers. See Appendix K: Obtaining Support for
Your 3Com Products for details on how to register your product and get support from 3Com.
How to Use This Guide
This book covers these topics:
Chapter 1: VCX V7122 SIP Overview
Chapter 2: VCX V7122 SIP Physical Description
Chapter 3: Installing the VCX V7122
Chapter 4: Getting Started
Chapter 5: Web Management
Chapter 6: ini File Configuration of the VCX V7122
Chapter 7: Configuration Files
Chapter 8: Gateway Capabilities Description
Chapter 9: Diagnostics
Chapter 10: BootP/DHCP Support
Chapter 11: SNMP-Based Management
Chapter 12: Selected Technical Specifications
Appendix A: VCX V7122 SIP Software Kit
Appendix B: The BootP/TFTP Configuration Utility
Appendix C: RTP/RTCP Payload Types and Port Allocation
Appendix D: Fax and Modem Transport Modes

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Appendix E: VCX V7122 Clock Settings
Appendix F: Customizing the VCX V7122 Web Interface
Appendix G: Accessory Programs and Tools
Appendix H: Software Upgrade Key
Appendix I: Release Reason Mapping
Appendix J: RADIUS Billing and Calling Card Application
Appendix K: Obtaining Support for Your 3Com Products
Conventions
Table 1 lists conventions that are used throughout this guide.
Table 1 Notice Icons
Icon Notice Type Description
Information note Information that describes important features or instructions.
Caution Information that alerts you to potential loss of data or potential
damage to an application, device, system, or network.
Warning Information that alerts you to potential personal injury or death.
Related Documentation
The following documents are available on the 3Com Partner Access website for the 3Com
VCX V7111 Gateway:
3Com VCX V7122 SIP VoIP Gateway Release Notes
3Com VCX V7122 SIP VoIP Gateway Installation Guide
Where “network” appears in this manual, it means LAN, WAN, etc. accessed via
the gateway’s Ethernet interface.
Documentation Comments
Your suggestions are important to us because we want to make our documentation more
useful to you.
Please send e-mail comments about this guide or any of the VCX 7111 documentation and
Help systems to:
[email protected]
Please include the following information with your comments:
Document title
Document part number (usually found on the front page)

3Com VCX V7122 SIP VoIP Gateway User Manual 11
Page number
Your name and organization (optional)
Example:
3Com VCX V7112 VoIP SIP Gateway User Manual
Page 25
Part Number 900-0255-01

3Com VCX V7122 SIP VoIP Gateway User Manual
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3Com VCX V7122 SIP VoIP Gateway User Manual 13
CHAPTER 1: VCX V7122 SIP OVERVIEW
The VCX V7122 SIP (Session Initialization Protocol) Voice over IP (VoIP) gateway enables
voice, fax, and data traffic to be sent over the same IP network. The VCX V7122 gateway
provides excellent voice quality and optimized packet voice streaming over IP networks.
The VCX V7122 uses the award-winning, field-proven DSP voice compression technology
used in other TrunkPackTM series products.
The VCX V7122 incorporates 1, 2, 4, 8 or 16 E1 or T1 spans for connection, directly to
Public Switched Telephone Network (PSTN) / Private Branch Exchange (PBX) telephony
trunks, and includes one or two 10/100 Base-TX Ethernet ports for connection to the
network.
The VCX V7122 supports up to 480 simultaneous VoIP or Fax over IP (FoIP) calls,
supporting various Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI)
protocols such as EuroISDN, North American NI2, Lucent 5ESS, Nortel DMS100 and others.
In addition, it supports different variants of Channel Associated Signaling (CAS) protocols for
E1 and T1 spans, including MFC R2, E&M immediate start, E&M delay dial/start, loop start
and ground start.
The VCX V7122 gateway, best suited for large and medium-sized VoIP applications, is a
compact device, comprising a 19-inch 1U chassis with optional dual AC or single DC power
supplies.
The deployment architecture can include several VCX V7122 gateways in branch or
departmental offices, connected to local PBXs. Call routing is performed by the gateways
themselves or by SIP Proxy(s).
The VCX V7122 gateway enables users to make low cost long distance or international
telephone/fax calls between distributed company offices, using their existing telephones/fax.
These calls are routed over the existing network ensuring that voice traffic uses minimum
bandwidth.
The VCX V7122 can also route calls over the network using SIP signaling protocol, enabling
the deployment of "Voice over Packet" solutions in environments where access is enabled to
PSTN subscribers by using a trunking media gateway. This provides the ability to transmit
voice and telephony signals between a packet network and a TDM network. Routing of the
calls from the PSTN to a SIP service node (e.g., Call Center) is performed by the VCX
V7122 internal routing feature or by a SIP Proxy.
Figure 1 below illustrates typical VCX V7122 gateway applications over VoIP Network.

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Figure 1 Typical VCX V7122 Gateway Application
SIP
Service
Node
LAN
PSTN
LAN
Telephone
LAN
SIP Proxy
Mediant 2000
E1/T1 PRI/CAS
Router
Mediant 2000
PBX - Branch B
E1/T1 PRI/CAS
Mediant 2000
PBX - Branch A
E1/T1 PRI/CAS
LAN
IPNetwork
Router Router
Router
Available Configurations
The VCX V7122 is provided in the following configurations.
E1 Available Configurations:
30 Channels on 1 E1 span with gateway-1 only
60 Channels on 2 E1 spans with gateway-1 only
120 Channels on 4 E1 spans with gateway-1 only
240 Channels on 8 E1 spans with gateway-1 only
480 Channels on 16 E1 spans with gateway-1 and gateway-2

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T1 Available Configurations:
24 Channels on 1 T1 span with gateway-1 only
48 Channels on 2 T1 spans with gateway-1 only
96 Channels on 4 T1 spans with gateway-1 only
192 Channels on 8 T1 spans with gateway-1 only
384 Channels on 16 T1 spans with gateway-1 and gateway-2
SIP Overview
SIP is an application-layer control (signaling) protocol used on the VCX V7122 for creating,
modifying, and terminating sessions with one or more participants. These sessions can
include Internet telephone calls, media announcements and conferences.
SIP invitations are used to create sessions and carry session descriptions that enable
participants to agree on a set of compatible media types. SIP uses elements called proxy
servers to help route requests to the user's current location, authenticate and authorize users
for services, implement provider call-routing policies and provide features to users.
SIP also provides a registration function that enables users to upload their current locations
for use by proxy servers. SIP, on the VCX V7122, complies with the IETF (Internet
Engineering Task Force) RFC 3261 (see http://www.ietf.org).
VCX V7122 VoIP SIP Supported Features
This section provides a high-level overview of some of the many VCX V7122 supported
features.
General Features
Superior, high quality PSTN gateway for Voice and Fax over IP calls.
Up to 16 E1/T1/J1 digital spans supporting various PRI and CAS protocols.
Compliant with SIP (RFC 3261).
Coders include: G.711, G.723.1, G.726, G.729A and NetCoder at 6.4 to 8.8 kbps,
negotiable per channel.
Echo Canceler with up to 128 msec tail length.
Silence suppression with Comfort Noise Generation.
Web management for easy configuration and installation.
Simple Network Management Protocol (SNMP) and Syslog support.
Simple Network Time Protocol (SNTP) support, the time-of-day can be obtained from a
standard SNTP server.
Hardware Features
Two 10/100 Base-TX Ethernet interface connections to the network, providing network
redundancy.
Compact, rugged 19-inch rack mount unit, one U high (1.75" or 44.5 mm), with two
compactPCI (cPCI) slots.
Optional cPCI slot for third-party CPU board.

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TP-1610/H.323 hot-swap cPCI board.
Optional dual redundant AC or a single DC power supply.
PSTN-to-SIP Interworking
The VCX V7122 gateway performs interworking between ISDN and CAS via E1/T1/J1 digital
spans and SIP IETF signaling protocol. 16 E1, T1 or J1 spans are supported (480 channels)
in a two modules gateway.
The VCX V7122 gateway supports various ISDN PRI protocols such as EuroISDN, North
American NI2, Lucent 5ESS, Nortel DMS100, Meridian 1 DMS100, Japan J1, as well as
QSIG (basic call). PRI support includes User Termination or Network Termination side.
ISDN-PRI protocols can be defined on an E1/T1 basis (i.e., different variants of PRI are
allowed on different E1/T1 spans).
In addition, it supports numerous variants of CAS protocols for E1 and T1 spans, including
MFC R2, E&M wink start, E&M immediate start, E&M delay dial/start, loop-start, and ground
start. CAS protocols can be defined on an E1/T1 basis (i.e., different variants of CAS are
allowed on different E1/T1 spans).
PSTN to SIP and SIP to PSTN Called number can be optionally modified according to rules
that are defined in gateway ini file.
Supported Interworking Features
Definition and use of Trunk Groups for routing IPPSTN calls.
B-channel negotiation for PRI spans.
ISDN Non Facility Associated Signaling (NFAS).
Supports SIP2QSIG IETF draft-ietf-sipping-qsig2sip-04.txt, including interworking
between 180/183 responses with Session Description Protocol (SDP) and Q.931
Progress message.
PRI to SIP Interworking of Q.931 Display (Calling name) information element.
PRI (NI-2) to SIP interworking of Calling Name using Facility IE in Setup and Facility
messages.
Configuration of Numbering Plan and Type for IPISDN calls.
Interworking of PSTN to SIP release causes.
Interworking of ISDN redirect number to SIP diversion header (according to IETF draft-
levy-sip-diversion-05.txt).
Optional change of redirect number to called number for ISDNIP calls.
Interworking of ISDN calling line Presentation & Screening indicators using RPID header
<draft-ietf-sip-privacy-04.txt>.
Interworking of Q.931 Called and Calling Number Type and Number Plan values using
the RPID header.
Supports ISDN en-block or overlap dialing for incoming TelIP calls.
Supports routing of IPTel calls to predefined trunk groups.
Supports a configurable channel select mode per trunk group.
Supports various number manipulation rules for IPTel and TelIP, called and calling
numbers.

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Option to configure ISDN Transfer Capability (per Gateway).
Supported SIP Features
The VCX V7122 SIP VoIP main features are:
Reliable User Datagram Protocol (UDP) transport, with retransmissions.
T.38 real time Fax (using SIP).
Note: If the remote side includes the fax maximum rate parameter in the SDP body of
the Invite message, the gateway returns the same rate in the response SDP.
Works with Proxy or without Proxy, using an internal routing table.
Fallback to internal routing table if Proxy is not responding.
Supports up to four Proxy servers. If the primary Proxy fails, the VCX V7122
automatically switches to a redundant Proxy.
Supports Proxy server discovery using Domain Name Server (DNS) SRV records.
Proxy and Registrar Authentication (handling 401 and 407 responses) using Basic or
Digest methods.
Supported methods: INVITE, CANCEL, BYE, ACK, REGISTER, OPTIONS, INFO,
REFER, UPDATE, NOTIFY, PRACK and SUBSCRIBE.
Modifying connection parameters for an already established call (re-INVITE).
Working with a Redirect server and handling 3xx responses.
Early Media (supporting 183 Session Progress).
PRACK reliable provisional responses <RFC 3262>.
Call Hold and Transfer Supplementary services using REFER, Refer-To, Referred-By,
Replaces and NOTIFY messages.
Supports RFC 3327 – Adding “Path” to Supported header.
Supports RFC 3581 – Symmetric Response Routing.
Session Timer <draft-ietf-sip-session-timer-10.txt>.
RFC 2833 Relay for Dual Tone Multi Frequency (DTMF) digits, including payload type
negotiation.
DTMF out-of-band transfer using:
INFO method <draft-choudhuri-sip-info-digit-00.txt>
INFO method, compatible with Cisco gateways
NOTIFY method <draft-mahy-sipping-signaled-digits-01.txt>.DTMF out-of-band
transfer using INFO method (draft-choudhuri-sip-info-digit-00.txt)
Can negotiate coder from a list of given coders.
Supported coders:
G.711 A-law 64 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.711 µ-law 64 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.723.1 5.3, 6.3 kbps (30, 60, 90, 120, 150 msec)
G.726 32 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.729A 8 kbps (10, 20, 30, 40, 50, 60, 80, 100, 120 msec)
G.729B is supported if Silence Suppression is enabled.

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NetCoder 6.4, 7.2, 8.0 and 8.8 kbps (20, 40, 60, 80, 100, 120 msec).
Transparent
For more updated information on the gateway’s supported features, see the latest VCX
V7122 & TP-1610 SIP Release Notes.

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CHAPTER 2: VCX V7122 SIP PHYSICAL
DESCRIPTION
This section provides detailed information on the VCX V7122 hardware components, the
location and functionality of the LEDs, buttons and connectors on the front and rear panels.
General
The VCX V7122 gateway comprises the following hardware components:
A 19-inch 1U high rack mount chassis (see The VCX V7122 Chassis on page 20).
A single compactPCI™ TP-1610 board (see The TP-1610 Board on page 20).
A single TP-1610 Rear Transition Module (RTM) (see Rear Transition Module on
page 23).
A single available cPCI slot for an optional third-party CPU board (see Optional CPU
Board on page 24).
Figure 2 shows the front view of the VCX V7122 media gateway.
Figure 2 VCX V7122 Front View
Table 2 VCX V7122 Front View Component Descriptions
Item # Label Component Description
1 FAULT Dual AC Power LED.
2 cPCI board locking screws.
3 cPCI latches.
4 TP-1610 cPCI board, 16-trunk configuration.
1 7
2
3
6
5
4
86 910
11

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5 Status LED Indicators.
6 T1/E1 STATUS E1/T1 Trunk Status LED Indicators.
7 ETH Ethernet LED Indicators.
8 Reset button.
9 cPCI LED Indicators.
10 Power and Fan LEDs.
11 An available cPCI slot for an optional third-party CPU board.
The VCX V7122 Chassis
The VCX V7122 chassis is an industrial platform, 19” wide, 1U high and 12” deep that
houses the TP-1610 board in its front cage, slot #1 (the lower slot) and the TP-1610 RTM in
its rear cage, slot #1 (the lower slot).
Slot # 2 in the VCX V7122 chassis’ front and rear cages can optionally be used by customers
for a CPU board.
See Table 3 for detailed description of the chassis’ LED indicators.
Table 3 Chassis LED Indicators
Location Color Function
Right side of front panel Green The power is on.
Right side of front panel Red Fan failure - indicates that any of the internal fans has
significantly reduced its speed or has frozen.
Left side of front panel Red
Power supply failure - indicates that one of the two AC
redundant power supplies is faulty or disconnected from the
AC/mains outlet. (This LED is only relevant for the dual AC
power supply).
Power Supply
The VCX V7122 power supply is available in three configuration options:
Single universal 100-240 VAC 1 A max, 50-60 Hz.
Dual-redundant 100-240 VAC 1.5 A max, 50-60 Hz.
-48 VDC power supply suitable for field wiring applications.
The TP-1610 Board
The VCX V7122 is populated by a single compactPCI board, the TP-1610 (see Figure 3 on
page 21). The TP-1610 is a high-density, hot-swappable, cPCI resource board with a
capacity of up to 480 ports, supporting all necessary functions for voice, data and fax
streaming over IP networks. The TP-1610 is composed of one or two identical media
gateways modules: Gateway-1 and Gateway-2, each containing 240 DSP channels. These
media gateways are fully independent, each gateway having its own MAC (Media Access
Control) and IP addresses and LED indicators. The TP-1610 board is supplied with a rear I/O