YDI Link CX-24 User manual

Version 1.0 February 2004MNL-500224-001

Link CX-24 User’s Manual
Version 1.0 Page i February 2004
This document applies to the YDI Wireless (YDI) release of the Link CX-24 product line and to all
subsequent versions and releases of the hardware or software unless otherwise indicated in a new
version or an update package for this edition. The products described in this document are products of
YDI Wireless or its licensers.
YDI Wireless reserves the right to make changes to any products described herein at any time without
notice. YDI Wireless does not assume any responsibility or liability arising out of the application or use of
any product described herein, except as expressly agreed to in writing by YDI Wireless, nor does the
purchase or use of a product from YDI Wireless convey a license under any patent rights, copyrights,
trademark rights, or any other of the intellectual property rights of YDI Wireless or third parties.
Use, duplication, or disclosure by the U.S. Government is subject to restrictions of FAR 52.227-14 (g) (2)
(6/87) and FAR 52.227-19 (6/87), or DFAR 252.227-7015 (b) (6/95) and DFAR 227.7202-3 (a).
The software described in this document is furnished under a license agreement or nondisclosure
agreement. The software may be used or copied only in accordance with the terms of the agreement. It is
a violation of YDI Wireless proprietary rights to copy the software on any medium except as specifically
allowed in the license or nondisclosure agreement.
The Link CX-24 product line is covered by one or more of the following United States Patents: No.
5,577,029, No. 5,654,968, No. 5,682,403, No. 5,721,735, No. 5,734,699, No. 5,734,979, No. 5,761,195,
No. 5,781,582, No. 5,818,824, No. 5,842,138, No. 5,887,256, No. 5,953,651, No. 5,957,464, No.
5,999,813, No. 6,070,071, No. 6,078,823, No. 6,081,716, No. 6,101,400, No. 6,169,907, No. 6,173,177,
No. 6,212,395, No. 6,269,255, No. USP D 391,967, No. USP D 391,968, No. USP D 397,693.
Changes or modifications not expressly approved by YDI Wireless in writing can void the user’s authority
to operate this equipment.
IMPORTANT OPERATING NOTICE
This device is to be exclusively used for fixed point-to-point operation with directional
antennas.
PROFESSIONAL INSTALLATION REQUIRED
The Link CX-24 must be installed as a system by experienced antenna installation
professionals who are familiar with Radio Frequency (RF) issues such as gains and
losses, as well as local building and safety codes. Failure to do so will void the product
warranty and may expose the end user to excessive RF hazard.
Regulations regarding maximum antenna gains, power output and maximum permissible
exposure vary from country to country. It is the responsibility of the end user to operate
within the limits of these regulations and to ensure that the professional installers who
install this device are aware of these regulations. All antennas are intended to be installed
outdoors.

Link CX-24 User’s Manual
Version 1.0 Page ii February 2004
MICROWAVE RADIO RADIATION WARNING
When installed properly, the Link CX-24 radio equipment complies with the limits for
human exposure to radio frequency (RF) fields adopted by the Federal Communications
Commission (FCC). All YDI Wireless microwave radio equipment is designed so that
under normal working conditions, microwave radiation directly from the radio is negligible
when compared with the permissible limit of continuous daily exposure recommended in
the United States by ANSI/IEEE C95.1-1991 (R1997), Safety Levels with Respect to
Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz.
Microwave signal levels that give rise to hazardous radiation levels can exist within
transmitter power amplifiers, associated RF multiplexers, and antenna systems. Never
look into the front of an open RF connection or RF antenna as eyes are particularly
vulnerable to radiation. Do not disconnect RF coaxial connectors, open microwave units,
or break down any microwave screening while the radio equipment is operating.
FCC NOTICE
This device complies 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: The manufacturer is not responsible for any radio or TV interference caused by
unauthorized modifications to this equipment. Such modifications could void the user's
authority to operate the equipment.
These products are labeled with one of the following FCC ID numbers:
FCC ID: NM5-CX-DS3-ETH-24
©
2004 YDI Wireless. All Rights Reserved. No part or parts of this document may be reproduced,
translated, stored in any electronic retrieval system or transmitted, in any form or by any means,
electronic, mechanical, photocopied, recorded or otherwise, without the prior written permission of YD
I
Wireless.

Link CX-24 User’s Manual
Version 1.0 Page iii February 2004
TABLE OF CONTENTS
Section 1 Overview 1
1.1 Description ....................................................................................................................................1
1.2 Regulatory Information..................................................................................................................1
1.3 Products ........................................................................................................................................1
1.4 Applications...................................................................................................................................2
1.5 System Overview ..........................................................................................................................2
1.6 Features ........................................................................................................................................4
1.7 Link CX-24 Basic Structure ........................................................................................................... 4
1.8 Typical Applications .................................................................................................................... 11
1.9 Specifications .............................................................................................................................. 11
Section 2 Installation 12
2.1 Introduction .................................................................................................................................12
2.2 Planning a Link CX-24 Network ..................................................................................................12
2.3 Site Planning ...............................................................................................................................13
2.4 Planning Element and Network Management Ethernet Links ....................................................14
2.5 Planning DS-3 Links....................................................................................................................15
2.6 Power Planning ...........................................................................................................................15
2.7 Transmit Power Planning ............................................................................................................15
2.8 Radio Link Planning ....................................................................................................................16
2.9 Before Installing ..........................................................................................................................18
2.10 Initial Configuration .....................................................................................................................21
2.11 Mounting the Link CX-24.............................................................................................................30
2.13 Completing the Link CX-24 Installation.......................................................................................33
2.14 Aligning the Antenna ...................................................................................................................35
2.15 Acceptance Testing.....................................................................................................................37
2.16 Final Link CX-24 Configuration ...................................................................................................40
2.17 Updating the Link CX-24 Software..............................................................................................41
Section 3 Monitoring and Trend Analysis 43
3.1 Built-In Web Server Interface......................................................................................................43
3.2 SNMP Network and Element Management Systems ................................................................. 43
Section 4 Troubleshooting the Link CX-24 45
4.1 Troubleshooting Tables............................................................................................................... 45
4.2 Using the Link CX-24 LEDs ........................................................................................................45
4.3 Using RSSI..................................................................................................................................45
4.4 Using a Web Browser .................................................................................................................46
4.5 Customer Support Services ........................................................................................................46
Appendix A - Interface Cable Pinouts 47
Appendix B - Technical Specifications 49
Appendix C - Using the Web-Based GUI User Interface 52
C-1 Web Browser Requirements..........................................................................................................52
C-2 Connecting A Web Browser...........................................................................................................52
C-3 Accessing the Link CX-24 Web Pages ..........................................................................................52
C-4 Link CX-24 Web Pages..................................................................................................................52

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Appendix D - Grounding and Lightning Protection 58
D-1 Overview ........................................................................................................................................58
D-2 Grounding ......................................................................................................................................58
D-3 Lightning Protection ....................................................................................................................... 59
Appendix E - Enterprise MIBs and Traps 61
E-1 Enterprise MIBs..............................................................................................................................61
E-2 Enterprise Traps.............................................................................................................................79
Bibliography 80
FIGURES
Figure 1.1 – Link CX-24 Power Supply ..................................................................................................2
Figure 1.2 – Typical Radio Link Configurations...................................................................................... 3
Figure 1.3 – Link CX-24 Star Network.................................................................................................... 3
Figure 1.4 – Link CX-24 Interface Connectors and Indicators ...............................................................5
Figure 1.5 – Integral Antenna and Link CX-24 Radio.............................................................................7
Figure 2.1 – Preventing Multi-path Fading from Ground-Level Surfaces ............................................. 13
Figure 2.2 – Typical EMS/NMS Ethernet Connections ........................................................................15
Figure 2.3 – Link CX-24 Orderable Parts .............................................................................................20
Figure 2.4a – Link CX-24 Configuration Setup.....................................................................................22
Figure 2.4b – Link CX-24 Positive-Ground Power Connections ..........................................................23
Figure 2.4c – Link CX-24 Negative-Ground Power Connections ......................................................... 23
Figure 2.5 – Typical DS-3 Link CX-24 Monitor Web Page ................................................................... 24
Figure 2.6 – Typical Ethernet Link CX-24 Monitor Web Page..............................................................25
Figure 2.7 – Typical DS-3 Link CX-24 Commission Radio Web Page.................................................25
Figure 2.8 – Typical Ethernet Link CX-24 Commission Radio Web Page ...........................................26
Figure 2.9 – Typical DS-3 Link CX-24 Commission Manager Web Page ............................................27
Figure 2.10 – Typical Ethernet Link CX-24 Commission Manager Web Page .................................... 28
Figure 2.11 – Typical Link CX-24 DS-3 Test Web Page ...................................................................... 29
Figure 2.12 – Link CX-24 Mounting Components ................................................................................30

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Figure 2.13 – Setting the Link CX-24 Polarization – Vertical Polarization Shown ............................... 31
Figure 2.14 – Detail Showing Assembly of Pole Mounting Bracket to Unit (Vertical Polarization) ......32
Figure 2.15 – Attaching the Link CX-24 Unit to the Pole...................................................................... 33
Figure 2.16 – Connecting an Earth Ground to the Link CX-24............................................................. 34
Figure 2.17 – Final Line-of-Sight Adjustment and Signal Optimization................................................36
Figure 2.18 – Typical DS-3 Update Software Web Page .....................................................................41
Figure 2.19 – Typical Ethernet Update Software Web Page................................................................ 41
Figure C.1 – Link CX-24 Login Window (all models)............................................................................52
Figure C.2 – Link CX-24 DS-3 Monitor Web Page ............................................................................... 53
Figure C.3 – Link CX-24 DS-3 Commission Radio Web Page............................................................. 53
Figure C.4 – Link CX-24 DS-3 Commission Manager Web Page........................................................54
Figure C.5 – Link CX-24 DS-3 Test Web Page .................................................................................... 55
Figure C.6 – Link CX-24 DS-3 Update Software Web Page ................................................................55
Figure C.7 – Link CX-24 Ethernet Monitor Web Page .........................................................................56
Figure C.8 – Link CX-24 Ethernet Commission Radio Web Page ....................................................... 56
Figure C.9 – Link CX-24 Ethernet Commission Manager Web Page .................................................. 57
Figure C.10 – Link CX-24 Ethernet Test Web Page ............................................................................ 57
Figure C.11 – Link CX-24 Ethernet Update Software Web Page.........................................................57

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TABLES
Table 1.1 – Link CX-24 Models ..............................................................................................................4
Table 1.2 – Link CX-24 Interface Connectors and Indicators................................................................. 6
Table 2.1 – Maximum Power Output by Model Configuration.............................................................. 16
Table 2.2 – Radio Link Planning Worksheet ........................................................................................ 16
Table 2.2 – Radio Link Planning Worksheet (continued) .....................................................................17
Table 2.2 – Radio Link Planning Worksheet (continued) .....................................................................18
Table 2.3 – Link CX-24 Radio Orderable Parts ....................................................................................20
Table 2.4 – Required Installation Tools ................................................................................................21
Table 2.5 – Physical Installation Checklist ........................................................................................... 37
Table 2.6 – Electrical Connection Checklist .........................................................................................38
Table 2.7 – DS-3 Internal Circuit and Radio Link Checklist .................................................................39
Table 2.8 – Ethernet Internal Circuit and Radio Link Checklist ............................................................ 39
Table 4.1 – Symptoms and Probable Causes ...................................................................................... 45
Table 4.2 – LEDs and Alarm Indication Modes ....................................................................................45
Table A.1 – DS-3 Data Cables ............................................................................................................. 47
Table A.2 – 10/100 Ethernet Data or Control Cable............................................................................. 47
Table A.3 – DC Power Cable................................................................................................................47
Table A.4 – 10/100 Ethernet Crossover Cable.....................................................................................48
Table A.5 – RS-232 CLI Craft PC Cable ..............................................................................................48
Table B.1 – Link CX-24 DS-3 or Ethernet Version (24 GHz) ...............................................................49
Table B.1 – Link CX-24 DS-3 or Ethernet Version (24GHz) (continued) .............................................50
Table B.2 – Integral Reflector Antenna ................................................................................................51

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Section 1
Overview
1.1 Description
This manual is intended for the technical personnel who will install and operate the Link CX-24. Such
personnel are typically experienced and skilled technicians familiar with on site, physical installation and
connection of equipment, including maintenance work. It is also intended for system administration
personnel performing initial configuration and subsequent system reconfiguration, as well as current
system maintenance activities.
1.2 Regulatory Information
1.2.1 FCC Compliance
The Link CX-24 is FCC certified for use in the 24 GHz unlicensed band in the United States.
24GHz (24.05-24.250 GHz)
When deployed in an area regulated by the FCC, Link CX-24 radios operate under the FCC Part 15.249
band regulations for intentional radiators in a point-to-point configuration. The Link CX-24 radios are
equipped with an integral antenna.
1.2.2 Other Regulation Compliance
Other countries have varying RF licensing and operating requirements, and it is imperative that operators
and professional installers ensure that the Link CX-24 is configured and installed per regional regulations.
1.3 Products
The Link CX-24 product is a cost-effective, all-outdoor, pole-mounted, high-capacity, line-of-sight (LOS)
digital radio transmission system, operating in the license-exempt 24.05-24.250 GHz (24GHz) frequency
band. The Link CX-24 can be used for the following applications: point-to-point or building-to-building,
WLL (wireless local loop), backup solutions, temporary links, and mesh cellular backhaul.
• The Link CX-24 DS-3 and 10/100 versions conform to the FCC (Federal Communications
Commission) Part 15.249 It operates at up to 0 dBm average transmit power, and is intended for
medium-distance use.
The Link CX-24 provides either a standard DS-3 (44.736 Mbps) interface adhering to Bellcore GR-499-
CORE (DSX-3) standards, or provide two Ethernet 10/100Base-T interfaces adhering to IEEE 802.3
standards, with a combined nominal line rate of 45 Mbps.
Each Link CX-24 is powered by a 110/220 VAC to 48 VDC power supply (see Figure 1.1).

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Figure 1.1 – Link CX-24 Power Supply
1.4 Applications
The Link CX-24 product line is designed to serve the following communications markets:
• Internet Access and Backhaul Systems: Used by Internet Service Providers (ISPs).
• Private Networks: Wireless Bridged LANs and WANs.
• PCS/PCN and Cellular Networks: High-speed links between base stations.
• Wireless Local Loop Networks: Fixed wireless, used by Local Exchange Carriers (LECs).
• Business Bypass or Local Exchange Bypass: Provided by Competitive Access Providers (CAPs)
and Competitive Local Exchange Carriers (CLECs).
1.5 System Overview
Each Link CX-24 consists of a Link CX-24 radio, with integral antenna as shown in Figure 1.2, along with
external power and data cabling. In a typical installation, the Link CX-24 radio with integral antenna is
mounted outdoors, usually on a tower or building.
See Figure 1.2. A radio system, or link, contains two Link CX-24 radios with integral antenna, installed at
each end of the link, separated by a line of sight transmission path. Frequency band, terrain, actual line-
of-sight and environmental conditions influence the range of operation and path performance.
The Link CX-24 carries one full-duplex DS-3, or Ethernet channel, and is powered by a 48-watt external
48 VDC power supply.

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Figure 1.2 – Typical Radio Link Configurations
Because the Link CX-24 offers both high and low channels in a single band, and can be installed with
horizontal or vertical polarization, up to four Link CX-24 radios can be mounted at each hub, or node, to
form part of a star or mesh network. See Figure 1.3.
Figure 1.3 – Link CX-24 Star Network
1H = Channel 1,
Horizontal
2V = Channel 2,
Vertical
1H 24
1V 24
2V 24 2H 24
This is one sample
configuration. Many other
combinations of channels
and frequencies are possible.

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1.6 Features
The Link CX-24 offers the following features:
• Robust all-outdoor enclosure.
• Integral antenna.
• Sturdy radio mounting systems for quick, accurate and reliable integral antenna alignment.
• Operates in the license-exempt 24.05-24.250GHz (24GHz) band.
• Full-duplex transmission:
• DS-3 (DSX-3, per Bellcore GR-499-CORE)
• Ethernet 10/100Base-T (per IEEE 802.3)
• Easy configuration, installation, operation, and maintenance.
• Integral web server for configuring, operating, and monitoring using an HTML-based web browser
GUI.
• Ethernet interface used with NMSs (Network Management Systems) or EMSs (Element
Management Systems) using SNMP (Simple Network Management Protocol) traps. Supports
MIB-II (Management Information Base II) and YDI Wireless enterprise MIB.
• ATPC (Automatic Transmit Power Control).
• Self Test, BER test mode, RF and digital loop-backs.
• Reed Salomon Forward Error Correction (FEC).
• Operating and backup software versions contained in Link CX-24 memory, operator-selectable.
1.7 Link CX-24 Basic Structure
1.7.1 Radio Links
Each radio link includes two Link CX-24 terminals. Each terminal consists of a Link CX-24 radio with an
integral 12” diameter reflector antenna. Generally, the Link CX-24 terminals are mounted outdoors on a
tower or building.
1.7.2 Data Stream
The DS-3 or Ethernet data signals enter the Link CX-24 and are modulated into the RF data stream. The
RF radio signal radiates from the local antenna and propagates to the remote antenna. At the remote
terminal, the received signal is demodulated and de-multiplexed, separating the payload data and the
overhead management data.
1.7.3 Link CX-24 Models
The Link CX-24 is manufactured in two configurations, namely versions with DS-3 or Ethernet carried
over the 24GHz link.
Link CX-24 models are described in Table 1.1.
Table 1.1 – Link CX-24 Models
Model Transmit
Band
Frequency
Band
Link
Carries Antenna
CX-DS3-24-LO
CX-DS3-24-HI
High
Low 24.05-24.250 GHz DS-3 Integral 12” reflector
CX-ETH-24-LO
CX-ETH-24-HI
High
Low 24.05-24.250 GHz Ethernet (45 Mbps) Integral 12” reflector

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1.7.4 Mounting and Antenna Alignment
To ensure proper mounting and antenna alignment, YDI sells a mounting bracket designed for use with
the Link CX-24. The single bracket mounts one Link CX-24. The bracket is designed to provide rugged
mounting for the Link CX-24, while allowing fine adjustment for antenna alignment.
1.7.5 Interface Connectors and Indicators
See Figure 1.4 for a view of the Link CX-24 external connectors and indicators. The Link CX-24
connectors and indicators are described in Table 1.2.
Figure 1.4 – Link CX-24 Interface Connectors and Indicators

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Table 1.2 – Link CX-24 Interface Connectors and Indicators
Note: For connector pin-outs, refer to Appendix A.
No. Name Component Description From Note
1 POWER
Male 4-Pin
Circular
Connector
Power input
plug Power Supply Accepts ±21 to ±60 VDC
2 CRAFT
Female 4-Pin
Circular
Connector
RS-232
receptacle
Asynchronous
laptop port
1200 to 115,200 baud,
used only for tech support
troubleshooting
3 RSSI Female BNC
Connector
Receive Signal
Level Indicator Voltmeter Verifies RF signal strength, used to align antenna
4 OUT Female TNC
Connector
DS-3 data from
the radio link
DS-3 data
equipment --
5 IN Female TNC
Connector
DS-3 data to
the radio link
DS-3 data
equipment --
6 ETHERNET 2
Female 4-Pin
Circular
Connector
10/100Base-T
transmit and
receive
receptacle
Ethernet
equipment
For Ethernet data or link to
SNMP or Web manager,
or use to daisy-chain
Ethernet port to next Link
CX-24 in cascade
7 ETHERNET 1
Female 4-Pin
Circular
Connector
10/100Base-T
transmit and
receive
receptacle
Ethernet
equipment (Same as ETHERNET 2)
PWR/LCL ALM Green LED Power/Local
Alarm Status
ON = Power OK, no alarm,
Flashing = Local alarm,
OFF = Power off.
RF LINK Green LED Radio Link
Status
ON = Rcv. OK,
OFF = Link Alarm.
DATA Green LED DS-3 Status ON = OK (no LOS),
OFF = LOS.
ENET 2 Green LED Ethernet Status
ON = OK,
Flashing = data,
OFF = No conn.
8
ENET 1 Green LED Ethernet Status
--
ON = OK,
Flashing = data,
OFF = No conn.

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1.7.6 Cables
To ensure longevity in an outdoor environment, YDI sells various cables designed for use with the Link
CX-24.YDI offers the following weather-resistant cables:
• DS-3, Ethernet data cables and the power cables are offered in 25 m (82 ft.), 50 m (164 ft.), and
100 m (328 ft.) lengths.
• A 6 m (19.7 ft.) Ethernet cable is available to route the Ethernet signal between two Link CX-24 in
the same location, or when you are configuring the Link CX-24 from a Craft PC.
• A 6 m (19.7 ft.) RS-232 4-pin Circular-to-DB9 Craft cable is available to connect a Craft PC to a
Link CX-24 for future CLI applications.
All of the cables described above include weather-resistant connectors.
1.7.7 Integral Antenna
The integral antenna is a 12” diameter reflector antenna mounted directly on the Link CX-24 radio
chassis, as shown in Figure 1.5. All RF connections between the integral antenna and the Link CX-24
radio are made internally, eliminating the need for external coaxial cabling. Because the integral antenna
is sealed onto the Link CX-24 chassis, the Link CX-24 and integral antenna are mounted as a unit, and
share the same environmental protection. An arrow on the connector side of the Link CX-24 chassis
indicates the antenna polarization (either vertical or horizontal).
Figure 1.5 – Integral Antenna and Link CX-24 Radio
Integral antenna
Link CX-24 radio

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1.7.8 Configuration, Operation, and Monitoring
The Link CX-24 and radio link are configured, operated and monitored through one of five user interfaces.
The five interfaces are:
• A built-in web server GUI hosted by the Link CX-24, which can be accessed by any local or
remote computer equipped with a web browser. This is the interface most operators will use to
interact with the Link CX-24. The web browser can access the Link CX-24 built-in web server
through either the ETHERNET 1 or ETHERNET 2 port.
Note that the ETHERNET 1 and ETHERNET 2 ports are functionally equivalent, and that they are
both served by an onboard Ethernet controller. The controller automatically switches polarity on
the transmit and receive pairs when they are reversed, eliminating the need for crossover cables.
• SNMP traps, which communicate with MIB-II compliant NMSs (Network Management Systems)
and EMSs (Element Management Systems). This interface is used by operators who want real-
time notification of radio problems. The Link CX-24 sends SNMP traps to NMSs and EMSs over
Ethernet links through either the ETHERNET 1 or ETHERNET 2 port.
• An ASCII command line interface, accessible through the RS-232 Craft port, or through the
ETHERNET 1 or ETHERNET 2 port using telnet. This interface is primarily used by YDI technical
support personnel when performing detailed troubleshooting.
• The RSSI port, providing a DC voltage level proportionate to the received RF signal level, and
allowing installers to use a DC voltmeter to fine-tune antenna alignment. This interface is primarily
used during installation, but the current RSSI measurement is also available via the Link CX-24
built-in web server or via SNMP polls.
• Five LEDs that provide visual alarm status. They verify proper operation of the Ethernet ports,
DS3 ports, and radio link, and indicate proper power input and radio operation. These LEDs are
usually used during installation to provide a quick product verification.
1.7.9 SNMP
The Link CX-24 radio supports SNMP network management. SNMP is a protocol that defines the method
of communicating with and controlling network devices.
Devices that support the SNMP protocol can be queried for their status and other device information.
Some devices allow changing device settings or configurations using SNMP commands. The device
settings and other device data are available as variables. They are defined in the standard Management
Information Base (MIB) file, provided by the device manufacturer. The SNMP manager uses a database
to hold lists of variables that can be accessed for each device on the network. The device data can be
displayed in tables, graphs, or saved in a file.
1.7.10 Link CX-24 Network Management Architecture
Link CX-24 software network management is comprised of two main items:
• SNMP based Network Management System (NMS) application in the network management
workstation.
• SNMP agent in the Link CX-24.
The workstation manages all Link CX-24 assigned unique IP addresses. The workstation also provides a
graphical display of the network objects showing the status, performance, and configuration parameters
of each Link CX-24 radio.
The SNMP local agent is a standard MIB-II compliant software module that resides in each Link CX-24.
The agent collects information from different Link CX-24 components as defined in the Management
Information Base (MIB) structure. The Link CX-24 incorporates both standard and private MIBs.
Different Link CX-24s are distinguished by their customer-assigned IP addresses. The Web browser

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communicates with the Link CX-24 using TCP/IP (Transmission Control Protocol/Internet Protocol) and
HTTP (Hyper Text Transfer Protocol).
The NMS data transfer between the manager and the agents is accomplished using either polling or
trapping techniques.
Polling
The NMS polls each Link CX-24 SNMP agent at specific intervals. These are set according to user
requirements during SNMP NMS configuration.
Traps
The Link CX-24 agent sends an SNMP trap to the manager whenever a predefined event occurs. Groups
of traps can be defined according to their level of severity. The operator can choose to enable or disable
any traps or group of traps according to their level of severity (and his or her own security level). Traps
can be logged using any standard SNMP manager.
1.7.11 NMS Connectivity
The NMS workstation can access any Link CX-24 using its IP address. The NMS workstation can connect
to each Link CX-24 using any of the following methods:
• 10/100 Base-T Ethernet – accessing Link CX-24s via a LAN through hubs, switches or routers.
• Cascading Ethernet links transport NMS information between collocated Link CX-24s. This is
done by daisy-chaining the ETHERNET 1 and ETHERNET 2 ports between Link CX-24 radios
using straight-pinned or crossover Ethernet cables.
1.7.12 Web-Based GUI Access Security
Access to the Web-based GUI (graphical user interface) is limited by username and password, which is
available at different levels of security as follows:
• User – Read only privilege.
• Administrator – Read/partial write privilege. The administrator cannot cause a radio link to reset
by changing critical parameters.
• Supervisor – Full read/write privilege.
1.7.13 GUI Functions
The Web-based GUI monitors and controls the main functions of the Link CX-24. These functions are
listed below and detailed in the following sections:
• Configuration management
• Status and fault management
• Test activation and monitoring
• Software downloading
• Performance monitoring
Refer to Appendix C for Link CX-24 GUI operating instructions.
Configuration Management
The NMS software can be used to configure the parameters of the Link CX-24 radio, although this is
normally done using a web browser GUI. This includes the setup of templates with predetermined default
values, relating to both the parameters of common element types and the validation of parameter values.
It also includes saving and loading configuration files for individual Link CX-24 radios.
The NMS also controls the uploading and downloading of individual parameter values, and complete
configuration setups.

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Parameter configuration is terminal-oriented. Every configuration session deals with the Link CX-24 as
accessed by its particular IP address. Some of the parameters, such as RF channel number, link ID, etc.
affect the Link CX-24s on both ends of the radio link. Special care should be taken to activate the new
parameter values consistently on both ends of the radio link.
Status and Fault Management
Status and fault management involve a selective display of failures alerting the user to take actions
according to a decision making tree.
Some status indications and alarms may report conditions that pertain to both ends of the radio link.
These ends are commonly referred to as local and remote.
Note that the ‘local’ system is the Link CX-24 you are logged into, and the ‘remote’ Link CX-24 is the one
at the far end of the radio link. Thus, when you are logged into the far end Link CX-24 on a radio link that
terminates at your current physical location, the far end Link CX-24 is ‘local’ and the near end Link CX-24
is ‘remote’.
Test Activation and Monitoring
Following is a brief description of the tests that can be invoked and monitored by the Web based NMS.
Loop-backs
The loop-backs are incorporated into the radio to assist in detecting equipment/component/cable failure
during both installation and normal operations. Loop-backs are user initiated. The Link CX-24 DS-3 and
versions support RF and various interface loop-backs. (Note that loop-backs are not supported on the
Link CX-24 Ethernet versions, as any loop-back could result in an immediate data storm. Instead, YDI
recommends that customers use external equipment to Ping (use Packet Internet Groper) to test their
Ethernet paths.
BER Test
The following Bit Error Rate (BER) test is provided by the DS-3 and Link CX-24 versions:
• Pseudo random signal generator - capable of inserting a standard test signal for BER
measurements, and local- and remote-end loop-back functions.
• BER measurements of radio link performance under normal operating conditions.
Software Downloading
The Web-based user interface enables off-line operation and SNMP updates of files. Alternatively, when
on-line, configuration can be updated from the NMS to the Link CX-24 agent. Another way to upgrade
multiple Link CX-24s is to use FTP (File Transfer Protocol).
Note that the Link CX-24 can hold two software loads in memory, which facilitates upgrading and
reverting to a previous software version.
Some factory default software settings are always retained at the Link CX-24 to safeguard against
complete failure of communications caused by equipment restart.
Performance Monitoring
Each Link CX-24 gathers various statistics regarding radio link performance. The Web based user
interface can retrieve and analyze these statistics upon demand. In addition, the Web based user
interface manager processes its own general statistical data, based on the information that is received.
Current BER, Receive Signal Strength Indicator (RSSI), and other performance monitors are available for
the radio link.
The Web-based user interface is designed to easily interface with optional graph management software
packages for sophisticated performance presentation.

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1.8 Typical Applications
Link CX-24 gives the user great flexibility in setting up point-to-point radio links on a very cost effective
basis, because it avoids unnecessary outlays in expensive leased lines or fiber optic land-based lines.
Low cost of ownership makes return on investment (ROI) attractive compared to leased lines.
Link CX-24 advantages over copper/fiber alternatives include: short installation time, easy maintenance
using NMS software, independence of competing PTTs, avoiding the need to secure normal right-of-way
and/or physical installation permits, and ability to re-deploy in order to meet changing needs.
The simplicity of the Link CX-24 installation makes it easy for the user to implement Link CX-24 in a
variety of applications. It also means that the user can conveniently move a previously installed Link CX-
24 to a new location to meet the requirements of a changing system. Link CX-24 enables seamless future
software upgradability, protecting customer investment, reducing logistics, spare parts and product
stocking. The following sections briefly describe typical applications.
1.8.1 Internet (ISP)
The appetite for higher Internet access speeds requires faster ISP access and backhaul and ISP
connections to businesses. The Link CX-24 radio is perfectly suitable for both backbone and direct end-
user connectivity.
1.8.2 Private Network Wireless Bridged LANs and WANs
Link CX-24 radios are also used to provide communications links for private networks. For companies
requiring frequent communications into areas without extensive telecommunications infrastructure or in
areas where the cost of local access is high, installing and maintaining a Link CX-24 radio network can be
very cost effective. Typical users of private networks include: government agencies such as land
management, municipal agencies, and universities; large utilities such as oil, gas, and electric concerns;
and companies with widely deployed assets such as railroads and timber resource managers.
1.8.3 PCS/PCN and Cellular Networks
Cellular operators mainly use Link CX-24 radio links for Base Transceiver Station (BTS) interconnections,
BTS to Base Station Controller (BSC), and BSC to BSC interconnections.
1.8.4 Wireless Local Loop Networks and Local Exchange Bypass
Wireless systems in emerging markets were originally deployed to provide premium services to a mobile
subscriber base. However, middle and lower income countries have driven mobile network providers into
a new business - the substitution of wireless service for fixed service, so-called fixed wireless networks,
providing a cost-effective solution in situations where no wireless infrastructure exists. Wireless local loop
(last mile) networks are implemented mostly by Local Exchange Carriers (LECs).
Alternative carriers, such as Competitive Access Providers (CAPs) and Competitive Local Exchange
Carriers (CLECs) use radio links to establish standard telecommunications links between their customers’
sites and their own backbone networks. This way CAPs and CLECs provide their customers with cost-
effective local area telephone service and cheaper long distance services.
1.8.5 Business Bypass and Local Exchange Bypass
The Link CX-24 radio is a perfect solution for Business Bypass and Local Exchange Bypass applications.
1.9 Specifications
Refer to Appendix B for Link CX-24 specifications.

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Safety Warning
This antenna/transmitter device must be fixed-mounted on outdoor
permanent structures with a separation distance of at least 2 meters
(6.56 feet) from all persons. Users and installers must adhere to the
antenna installation instructions and transmitter operating conditions in
order to comply with the FCC’s RF exposure requirements.
Section 2
Installation
2.1 Introduction
The Link CX-24 is intended for professional installation only. However, this manual is also designed for
personnel who plan, operate and administer the Link CX-24 communication system. Please review the
entire manual before powering up or deploying any Link CX-24.
Note: It is strongly recommended that you configure and test the units prior to deploying them in the
field. Set up a “mini-network” that resembles your actual configuration as close as possible.
By using such a mock-up, troubleshooting potential problems will be much easier than if you
already installed the equipment in the field. Read through this entire Section 2 to understand
how to install the hardware.
2.2 Planning a Link CX-24 Network
As described in Section 1.8, the Link CX-24 can be used to support a number of applications. However,
the most common configuration is a point-to-point network. Point-to-point configurations (Figure 1.1) are
easiest to plan and implement, as the radio links merely transmit industry-standard formatted data from
one location to another.
Generally, the common points to consider when planning a Link CX-24 network are:
Line of Sight: Unlike some frequency bands, the Link CX-24 radios must be within line of sight of each
other. That is, the far-end antenna must be visible from the near-end antenna. If there are trees,
buildings, mountains, or other obstructions between the two antennas, the Link CX-24s on each end of
the radio link will be unable to communicate with each other. Make sure the Link CX-24 radios used in
each radio link are within line of sight of each other. Refer also to the Fresnel Zone Clearance section that
follows.
Fresnel Zone Clearance: There must be sufficient open space around the direct line of sight to minimize
interference with the radio beam. At a minimum, 60% of the first Fresnel zone of the path should be clear.
Even with clear line-of-sight, objects still may be near enough to the transmission path to cause problems.
Obviously, objects that stand directly in the transmission path obstruct the beam, causing a drop in signal
strength at the receiving end; in addition, objects and reflective surfaces that are in near proximity to the
path can cause signal interference and attenuation of the received signal.
Fresnel zones define the amount of clearance required for obstacles. These zones are series of
concentric ellipsoid surfaces that surround the straight-line path between the two antennas. The first
Fresnel zone is defined as the surface containing every point for which the distance from the transmitter
to any reflection point on the surface and then on to the receiver is one-half wavelength longer than the
CAUTION

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direct signal path. The Fresnel zone surrounds the direct signal path, so it affects objects to the side of
the path as well as objects directly in the path.
For a calculation of the Fresnel Clearance Zone, please refer to:
http://www.ydi.com/calculation/fresnel-zone.php.
Multipath Fading: See Figure 2.1. Because a Link CX-24 terminal typically transmits its strongest signals
in a cone-shaped pattern, some of the signal may be reflected from a nearby building, from water under
the signal path, or from other RF reflectors. This reflected signal can then be received by the far-end Link
CX-24 and superimposed on the main signal, usually degrading the signal strength. To avoid multi-path
fading, YDI recommends that you install the Link CX-24 antenna on the back, rather than the front, of
buildings to avoid multi-path fading from water or other ground-level surfaces, and that you plan radio
links away from nearby buildings.
Figure 2.1 – Preventing Multi-path Fading from Ground-Level Surfaces
External Interference: Because the Link CX-24 operates in an unlicensed band, YDI strongly
recommends that you use a spectrum analyzer at both ends of planned radio links, with the receiving
antenna as close to the proposed Link CX-24 antenna mounting spot as possible. Use a polarized
antenna, and scan for both horizontally- and vertically-polarized interfering radiation. If you find external
interference in either of the two (High or Low) bands, configure the Link CX-24 for the least-impacted
band. Refer to Table 2.2 for the High and Low bands for the Link CX-24 radio.
2.3 Site Planning
Each proposed Link CX-24 terminal site requires a site survey and plan for the following:
Power: The Link CX-24 radio requires a +/-21 to +/-60 VDC power source. Make sure required power
supply is available before installing the Link CX-24.
Mounting Point: The Link CX-24 is usually mounted on a vertical mast or pole mounted on a building or
a tower. The Link CX-24 mounting bracket can accommodate a 4.5 to 7.6cm (1.75” to 3” OD) diameter
mast or pole.
Grounding and Lightning Protection: The Link CX-24 radio requires adequate grounding and lightning