Laird CL024 User Manual

CL024

USER’S GUIDE
VERSION 2.0

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CL024 User Guide

Version 2.0

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FCC Notice

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.

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Version

Date

Changes

1.0

14 Aug 2013

Initial Release

1.1

19 Nov 2013

Updated Force 9600 Baud Recovery in Appendix

2.0

16 Dec 2013

Separated into two separate docs (Hardware Integration Guide and User
Guide).
Added a Related Documents section.

REVISION HISTORY

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CONTENTS

Contents ..................................................................................................................................................... 4

CL024 RF Transceiver ................................................................................................................................. 5

Overview ................................................................................................................................................. 5

Features ................................................................................................................................................... 5

Theory of Operation .................................................................................................................................. 6

Network Topologies ................................................................................................................................. 6

Modes of Operation ................................................................................................................................. 6

Transmit/Receive Mode ........................................................................................................................ 6

Command Mode ................................................................................................................................. 7

Spread Spectrum History ...................................................................................................................... 9

How Spread Spectrum Works .............................................................................................................. 9

Frequency Hopping Spread Spectrum ................................................................................................... 9

CL024 Security Features ....................................................................................................................... 9

Programming the CL024.......................................................................................................................... 10

Appendix I: Troubleshooting .................................................................................................................. 11

Force 9600 Baud Recovery ..................................................................................................................... 11

Related Documents and Files .................................................................................................................. 13

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 Server/Client architecture, with an unlimited number of Clients in a network
 API commands to control packet routing and acknowledgement on a packet-by-packet basis
 Durable industrial-grade enclosure
 Transparent operation; supports any legacy system
 Transmits around corners and through walls
 Reliable communication with serial UART speeds up to 460.8 Kbps
 Point-to-Point and Point-to-Multipoint configurations

CL024 RF TRANSCEIVER

The CL024 transceiver is a Frequency Hopping Spread Spectrum (FHSS) radio designed for license-free
operation in the 2.4 GHz Industrial, Scientific, and Medical (ISM) unlicensed band. The radio sustains a
standard asynchronous serial data stream between two or more radios. Housed in a compact and rugged die­cast enclosure, the radio is equipped to replace miles of serial cable with its wireless link. The radio features
an RS232 interface for integration into legacy data systems.

Overview

The CL024 uses Frequency Hopping Spread Spectrum (FHSS) 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 co-exist in the same area with limited interference.

CL024 transceivers operate in a Server/Client architecture. The Server radio transmits a beacon at the
beginning of every hop which Client radios utilize to synchronize their hopping. Communication between
devices cannot occur until both devices are synchronized. While an unlimited number of clients can
synchronize to the server’s beacon, communication between devices is limited to the chosen RF rate (either
500kbps or 230kbps). The CL024 radios come with options for enabling Full Duplex communication to
reserve slots for server and client transmissions and with Random-Backoff settings to ensure retransmissions
don’t collide.

CL024 radios implement a proprietary communication protocol to provide secure data transmissions. 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.

The CL024 transceivers use the 2.4 GHz ISM license free frequency band, which requires no additional
certifications when designing into a new or legacy data system.

Each unit is small and easily portable for use in mobile and temporary settings as well as fixed installations.
The CL024 configuration software enables custom configurations based on unique application requirements.

This document contains information about the hardware and software interface between a Laird CL024
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 the final
product meets all appropriate regulatory agency requirements listed herein before selling any product.

Note: CL024 modules are referred to as the “radio” or “transceiver”. Individual naming differentiates

product -specific features. The host (PC, Microcontroller or any connected device) is “OEM host.”

Features

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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 13.2 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 is actually received 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.

THEORY OF OPERATION

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 CL024s
have a Server/Client communication protocol, which supports Point-to-Point and Point-to-Multipoint
topologies. All clients must be in range of the server to maintain network synchronization and all
communicating devices must be in range of each other. Communication between out-of-range devices is also
possible using repeaters or Host systems that can direct the data through a Daisy Chain type topology.

Note: See the RM024 Embedded Module User Manual for more detailed information about setting up

different topologies using the advanced API features in the RM024 family of radios.

Modes of Operation

The CL024 has three different operating modes:

 Transmit/Receive Mode
 Command Mode

If the transceiver is not communicating with another radio, it is in Receive mode actively listening for packet
from another transceiver. A transceiver enters Transmit or Command mode when the OEM host sends data
over the serial interface. The contents of the data on the serial interface determine which of the two modes
the radio enters.

Transmit/Receive 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, see the RM024 Embedded
Module User Manual). To prohibit transceivers from receiving broadcast packets, Unicast only can be enabled.

When a radio has data to transmit, it will transmit it at the next available data slot.

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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 is interpreted as command data. Command Data may exist as either EEPROM Configuration or On­The-Fly commands. For more information on EEPROM Configuration and On-the-Fly commands, download
the RM024 Embedded Module User Manual).

Figure 1: Pending RF data received over RF

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Figure 2: Pending RF data in buffer flow

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Spread Spectrum History

Spread Spectrum, or SS, dates back to World War II, when actress Hedy Lamarr and composer George
Antheil were granted a U.S. patent on a simple frequency hopping continuous wave (CW) system. These early
research and development efforts tried to provide countermeasures for radar, navigation beacons, and
communications.

How Spread Spectrum Works

SS radio communication has long been a favourite technology of the military because it resists jamming and
is hard for an enemy to intercept. And now, this very same technology is widely used in the commercial,
industrial and even consumer markets. The reason: SS signals distribute over a wide range of frequencies and
then collect onto their original frequency at the receiver, making them so inconspicuous they are almost
transparent. Just as they are difficult to intercept by a military opponent, so are they unlikely to interfere with
other signals intended for business and consumer users – even ones transmitted on the same frequencies.

Spread signals are intentionally made to have a much wider band than the information they are carrying and
use special pseudo noise codes to make them more noise-like. It is this very characteristic that makes SS
signals difficult to detect, intercept, and demodulate. SS signals are hard to detect on narrowband equipment
because the signal's energy spreads over a much wider bandwidth. Further, SS signals are harder to jam
(interfere with) than narrowband signals and have a much lower probability of being intercepted, which is
why the military has used SS for so many years.

The spread of energy over a wide band makes SS signals less likely to interfere with narrowband
communications. Narrowband communications, conversely, cause little to no interference to SS systems
because the receiver effectively integrates the signal over a wide bandwidth to recover it.

Besides being hard to intercept and jam, spread spectrum signals are also difficult to exploit or imitate. Signal
exploitation is the ability of a non-network member to listen to a network and use information from the
network without being a valid network member or participant. Imitation is the act of falsely or maliciously
introducing false traffic or messages into a network. SS signals also are naturally more secure than
narrowband radio communications. Thus SS signals can have any degree of message privacy that is desired.
Messages can also be encrypted to any level of secrecy desired. The very nature of SS allows military or
intelligence levels of privacy and security with minimal complexity. While these characteristics may not be very
important to everyday business or consumer needs, these features are important to understand.

Frequency Hopping Spread Spectrum

An FHSS radio does just what its name implies – that is, it “hops” from frequency to frequency over a wide
band. The specific order in which it occupies frequencies is a function of a code sequence, and the rate of
hopping from one frequency to another is a function of the information rate.

CL024 Security Features

In addition to FHSS technology, Laird has implemented two levels of security in the CL024. All levels associate
with their own EEPROM parameter that you may program for permanent operation or change during system
operation in volatile memory using On-the-Fly commands (see the RM024 Embedded Module User Manual).
The two levels of security configure and establish a network of transceivers and are defined as the RF
Channel Number and System ID.

The RF Channel Number represents a specific hopping sequence and provides physical separation between
collocated networks. Thus, all transceivers in a network must use the same RF Channel Number. There are a
total of 43 or 79 Channel Numbers depending on the RF Rate chosen

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System ID is similar to a password character or network number and makes network eavesdropping more
difficult. A receiving radio will not go in session (communicate) with another radio on a different System ID.
There are a total of 256 System ID values.

PROGRAMMING THE CL024

Laird provides the easy-to-use CL024 Configuration Utility software for programming the CL024. The GUI
based software does not require any hardware configuration and works by itself. The software is compatible
with Microsoft® Windows. CL024s are plug-and-play devices that work with minimal or no configuration.

This section provides instructions for quick and simple setup of CL024 networks. The Laird Configuration
Utility User Manual provides a full description of the software tool’s functionality and features.

CL024 customers who need advanced features and functionality like Transmit/Receive API can unlock these
and other features in the Laird Configuration Utility software (see Enabling the Security Pane ). The Info
Center located on the Configure tab of the Laird Configuration Utility provides a quick explanation of all
CL024 features. Detailed descriptions for all available RM024 features are found in the RM024 Embedded

Module User Manual.

To program the CL024, follow these steps:

Start the Laird Configuration Utility. Click here to download. 1.
Connect a CL024 unit to the serial port on the PC (refer to the Serial Interface section). 2.
Attach the antenna to the CL024 unit; make sure the connection is secure. 3.
Connect the power supply to the CL024 unit. Make sure the Pwr LED is on. 4.
In the PC Settings tab in the Configuration Utility, select Connex024 from the Product drop-down. 5.
Click Find Port. 6.
From the Port drop-down menu, select the COM port that is connected to the CL024. 7.
Select the Baud Rate from the drop-down menu. 8.

Note: All CL024 units ship with a default baud rate of 115200 (unless units have been pre-

configured to match specific serial settings). If the Interface Baud Rate of the CL024 unit is
changed, the PC Setting baud rate must match the device baud rate to allow proper
programming of the units.

Click Open Port and verify that the Port (1/2) status bar at the bottom of the window shows the correct 9.

COM number, is OPEN, and CTS is Low.

Go to the Configure tab and click Read Radio. 10.
Change settings based on the type of network needed. 11.

Note: The Laird Configuration Utility automatically programs the mode (point-to-point or point-to-

multipoint) based on the radio’s current settings:

If the Destination Address field is set to any value other than
data only to the radio whose MAC matches that specified in the Destination Address field (point­to-point).

If the Destination Address field is set to

transmits to all transceivers in range with the same System ID and RF Channel (point-to­multipoint).

For more information on settings, see the Info Center in the Laird Configuration Utility or the

RM024 Embedded Module User Manual.

FF FF FF FF FF FF

FF FF FF FF FF FF

, it is set to Broadcast mode and

, the radio sends

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Problem

Solution

Read Radio displays error

message: “Radio not
responding.”

Make sure the PC Settings are correct and that the CL024 unit uses the
right serial cable. Refer to Error! Reference source not found..
If any other program using the same COM port as CL024 is open, close that
program and try to read the radio again.
Reset the radio by cycling power after each unsuccessful read.

Write Radio displays error:
“Radio not responding.”

Cycle radio power. Read the radio, make changes and click Write Radio.
Garbled Data received.

Check Data Encryption Standard settings.

Client Link LED won’t light.

Make sure the unit is connected to power. Cycle power to the radio.

Link LED is on, but data does
not get transmitted or
received.

Make sure the CL024 unit or units connect to the correct COM port.
Check the COM port settings for correct baud, parity, and either Hardware
or No Flow Control. May be caused by Flow Control set to Xon/Xoff.
Try increasing the Maximum Transmit Attempts (clients) and/or Broadcast
Attempts (servers) in small increments until communication is established.
Connect a Null Modem adapter between the client and its host device.
Check the Destination Address setting.

Note: The

After all changes are made, click Write Radio to save the changes. 12.

Show Defaults

current default settings of the radio.

button can display sample Radio Settings. These settings

APPENDIX I: TROUBLESHOOTING

may not

reflect the

If these tips do not resolve the problem, please call our toll free number at [phone], option 2 for
technical support. Hours are Monday through Friday, 8:00 am to 5:00 pm Central Standard Time.

Force 9600 Baud Recovery

To force the serial interface to a known value, perform the following steps (this also sets the RF Packet Size
and Interface Timeout to default values):

Remove power from the radio. 1.
Remove the screws on the case and slide the radio out. 2.
Reapply power to the radio. 3.
Press and hold both pushbuttons S1 and S2. (see Figure 3) 4.

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Figure 3: Switch buttons S1 and S2

Release pushbutton S2 while still holding down pushbutton S1. 5.
Wait 5 seconds, then release pushbutton S1. 6.
Connect the radio to the PC via a straight through cable. 7.
On the PC Settings tab, click Find Ports. 8.
Select the appropriate port from the drop-down list. 9.

Set the rest of the settings to: 10.

 Baud Rate: 9600
 Parity: None
 Handshaking: Hardware
 Data Bits: 8
 Stop Bits: 1

Under Options, ensure the
Ensure the

Port Status

Read/Write with AT Commands

is open. 12.

check box is selected. 11.

On the Configure tab, click Read Radio. 13.
Set the
Set the

Interface Baud Rate
Baud Rate

on the PC Settings tab to the baud rate you configured on the radio. 15.

to the appropriate value and click Write Radio. 14.

On the Configure tab, click Read Radio. 16.

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RELATED DOCUMENTS AND FILES

The following additional CL024 technical documents are also available from the Laird RM024 product page
under the Documentation tab:

 ConnexLink Product Brief
 CL024 Hardware Integration Guide

The following downloads are also available from the Laird CL024 product page:

 Configuration Utility
 USB Drivers