Laird CL4490 User Manual
CL4490
USER GUIDE
VERSION 3.2
wireless.support@lairdtech.com
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FCC Notice
CL4490 User Guide
Version 3.2
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Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
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WARNING: 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.
RF Exposure/Installation Instructions
WARNING: To satisfy FCC RF exposure requirements for mobile transmitting devices, this
equipment must be professionally installed such that the end user is prevented from
replacing the antenna with a non-approved antenna. The end user should also be prevented
from being within 20cm of the antenna during normal use with the exception of hands,
feet, wrists and ankles.
The preceding statement must be included as a CAUTION statement in manuals for OEM
products to alert users on FCC RF Exposure compliance.
Caution: Any change or modification not expressly approved by Laird could void the user’s authority to
operate the equipment.
CL4490 User Guide
Version 3.2
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Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
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REVISION HISTORY
Version
Date
Changes
Approved By
1.0
Initial Release
Chris Downey
1.1
Oct. 2012
Major changes and revisions throughout document
Chris Downey
2.0
5 Apr 2013
Major changes and revisions; updated format and data
Chris Downey
3.0
10 Dec 2013
Separated from Hardware Integration Guide
Sue White
3.1
4 Nov 2015
Updated links throughout document
Sue White
3.2
31 July 2017
Fixed warranty information to reflect one year warranty
Sue White
CL4490 User Guide
Version 3.2
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Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
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CONTENTS
CL4490 RF Transceiver ................................................................................................................................. 5
Overview .................................................................................................................................................... 5
Features ..................................................................................................................................................... 5
Status LEDs ................................................................................................................................................... 6
CL4490 ...................................................................................................................................................... 6
CL4490-PRO .............................................................................................................................................. 6
Theory of Operation .................................................................................................................................... 7
RF Architecture........................................................................................................................................... 7
Network Topologies ................................................................................................................................... 7
Modes of Operation ................................................................................................................................... 8
Security .................................................................................................................................................... 11
Programming the CL4490 .......................................................................................................................... 13
Appendix I: Troubleshooting .................................................................................................................... 15
Force 9600 Baud Recovery ....................................................................................................................... 18
Appendix II: Sync to Channel .................................................................................................................... 19
Sync to Channel - What is it and do I need to use it? ............................................................................... 19
How do I configure Sync to Channel? ...................................................................................................... 22
I’ve configured my radios, what’s next? ................................................................................................... 29
Related Documents and Files .................................................................................................................... 32
CL4490 User Guide
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CL4490 RF TRANSCEIVER
The CL4490 transceiver is a Frequency Hopping Spread Spectrum (FHSS) radio designed for license-free
operation in the 900 MHz Industrial, Scientific, and Medical (ISM) unlicensed band. The radio sustains a
standard asynchronous serial data stream between two or more radios out of the box. Housed in a compact
and rugged die-cast enclosure, the radio is equipped to replace miles of serial cable using a CL4490 RS232,
RS485, or USB interface.
This guide is for the CL4490 and CL4490-PRO. References to the CL4490 apply to the CL4490-PRO, unless
otherwise specified.
Overview
The CL4490 uses Frequency Hopping Spread Spectrum technology, where the units "hop" from frequency to
frequency many times per second using a specific hop pattern applied to all the transceivers in the same
network. A distinct hopping pattern is provided for each channel number, thereby allowing multiple
networks to coexist in the same area with limited interference.
CL4490 transceivers operate in a Point-to-Point or Point-to-Multipoint, client-server architecture. One
transceiver is configured as a server and there can be one or many clients. To establish communication
between transceivers, the server emits a beacon and upon detecting a beacon, a Radio Frequency (RF) link is
established with the client(s).
CL4490s implement a proprietary communication protocol to provide secure data transmissions. Using FHSS
technology ensures data reliability over long distances. The license-free frequency bands ensure that the units
are ready for use with no further certification requirements.
Each unit is small and easily portable for use in mobile and temporary settings as well as fixed installations.
The CL4490 configuration software enables custom configurations based on unique application requirements.
This document contains information about the hardware and software interface between a Laird CL4490
transceiver and an OEM host. Information includes the theory of operation, specifications, serial interface
definition, security information and mechanical drawings. The OEM is responsible for ensuring before the
final product is sold that it meets all appropriate regulatory agency requirements listed herein.
Additionally, this document contains a list of Related Documents and Files.
Note: CL4490 modules are referred to as the “radio” or “transceiver”. Individual naming is used to
differentiate product-specific features. The host (PC, Microcontroller, or any device connected to
the CL4490) is referred to as “OEM host”.
Features
Networking and Security
Retries and Acknowledgements
API Commands to control packet routing and
acknowledgement on a packet-by-packet basis
Frequency Hopping Spread Spectrum for security
and interference rejection
Customizable RF Channel number and System ID
Dynamic link analysis, remote radio discovery
Low latency and high throughput
Easy to Use
Continuous 76.8kbps RF data stream
Software selectable interface baud rates from
1200bps to 115.2kbps
Advanced configuration available using AT
commands
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STATUS LEDS
CL4490
Figure 1: CL4490 Status LEDs
Table 1 describes each of the CL4490 Status LEDs.
Table 1: CL4490 Status LEDs
LED
Color
Description
Pwr
Green
On. Indicates the unit is powered up.
Link
Red
On. Indicates the client unit(s) and server unit are in transmitting range of each other.
Note: A client’s Link LED lights when in range of the server. It is always lit on a server.
Rx
Green
When flashing, indicates the CL4490 is receiving data.
Tx
Red
When flashing, indicates the CL4490 is transmitting data.
CL4490-PRO
Figure 2: CL4490-PRO Status LEDs
Note: DIP Switches only appear on the CL4490-PRO.
Table 2 describes each of the CL4490 Status LEDs.
Table 2: CL4490-PRO status LEDs
LED
Color
Description
Pwr
Green
Device is powered up.
Link
Red
The client unit(s) and server unit are in range of each other.
Note: A client’s Link LED lights when in range of the server. It is always lit on a server.
RXD
Green
When flashing, the CL4490-PRO is receiving data.
TXD
Red
When flashing, the CL4490-PRO is transmitting data.
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THEORY OF OPERATION
RF Architecture
The CL4490 utilizes a server-client network where all clients synchronize their hopping to the server. The
server transmits a beacon during the first 1 ms of every hop (20 ms). The client transceivers listen for this
beacon; upon hearing it, they synchronize their hopping with the server and the LINK LED illuminates.
Each network should consist of only one server. Two servers should never use the same RF Channel number
in the same coverage area – the cross-talk between the two servers severely hinders RF communications. For
those applications requiring collocated servers, Laird recommends using the Sync to Channel feature, further
explained in Appendix II: Sync to Channel.
Network Topologies
Topology refers to the shape of a network, or the network's layout. The way different nodes in a network
connect to each other and how they communicate is determined by the network's topology. The CL4490s
support a Point-to-Point and a Point-to-Multipoint network topology.
Point-to-Point
A Point-to-Point system is a simple arrangement consisting of just two CL4490s programmed to the same
System ID and RF Channel (a single server/client pair). Sometimes referred to as a wireless bridge, a Point-toPoint link replaces a single communications cable. You might use a Point-to-Point link to connect a
programmable logic controller (PLC) to a remote monitoring station.
Point-to-Multipoint
Point-to-Multipoint systems have one base station, or access point, that controls communications with all of
the other wireless nodes in the network. This allows you to create a wireless network with multiple nodes. By
programming each CL4490 with a network-specific Channel Number and System ID, multiple networks can
coexist. You may configure collocated systems by programming each system with a network specific System
ID and RF Channel Number. See Figure 3 for an example of collocated point-to-multipoint systems.
Figure 3: Point-to-multipoint systems
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Modes of Operation
The CL4490 has three different operating modes:
Transmit Mode
Receive Mode
Command Mode
If the transceiver is not communicating with another radio, it is in Receive mode actively listening for a
beacon from the server. If the client determines that the beacon is from a server operating on the same RF
Channel and System ID, it synchronizes its hopping sequence to the server and illuminates the LINK LED. A
transceiver enters Transmit or Command mode when the OEM host sends data over the serial interface.
Transmit Mode
All packets sent over the RF are either Addressed or Broadcast packets. You may dynamically control
Broadcast and Addressed delivery with the API Control byte, which can be modified during operation with
On-the-Fly commands (for more information on APIs and On-the-Fly commands, download the AC4490
Embedded Module User Manual).
Addressed Packets
When sending an addressed packet, the RF packet sends only to the receiver specified
in the destination address. To increase the odds of successful delivery, Transmit Retries
are utilized. Transparent to the OEM host, the sending radio sends the RF packet to the
intended receiver. If the receiver receives the packet free of errors, it returns an RF
acknowledge within the same 20 ms hop. If a receive acknowledgement is not
received, the radio uses a transmit retry to resend the packet. The radio continues
sending the packets until either (1) it receives an acknowledgement, or (2) it has used
all transmit retries. The received packet only sends to the OEM host if and when it is
received free of errors.
Broadcast Packets
When sending a broadcast packet, the RF packet sends out to every eligible transceiver
on the network. To increase the odds of successful delivery, Broadcast attempts are
utilized. Transparent to the OEM host, the sending radio sends the RF packet to the
intended receiver(s).
Unlike Transmit Retries, all broadcast attempts are used regardless of when the RF
packet actually receives and without RF acknowledgements. If the packet is received on
the first attempt, the receiver ignores the remaining broadcast attempts. The received
packet is only sent to the OEM host if and when it is received free of errors.
Receive Mode
When a transceiver is not in Transmit or Command mode, it is in Receive mode listening for data. While in
Receive mode, the radio may receive subsequent data of up to 80 bytes every hop (20 ms).
To prohibit transceivers from receiving broadcast packets, enable Unicast only.
Command Mode
A radio enters Command mode when data is received over the serial interface from the OEM host and
contains the “AT+++” (Enter AT Command mode) command. Once in Command mode, all data received by
the radio interprets as command data. Command Data may exist as either EEPROM Configuration or On-theFly commands. For more information on On-the-Fly commands, download the AC4490 Embedded Module
User Manual.
CL4490 User Guide
Version 3.2
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
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Figure 4: Pending RF data in buffer flow
CL4490 User Guide
Version 3.2
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Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
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Figure 5: Pending RF data in buffer flow
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