AeroComm 4424200 Users Manual

LT4424-200

2.4 GHz OEM TRANSCEIVERS

Specifications Subject to Change

User’s Manual

Version 1.0.0

11160 THOMPSON AVENUE

LENEXA, KS 66219

[phone]

www.lairdtech.com

[e-mail]

DOCUMENT INFORMATION

Copyright
Information

This material is preliminary

Information furnished by Laird Technologies in this specification is believed to be accurate.
Devices sold by Laird Technologies are covered by the warranty and patent indemnification
provisions appearing in its Terms of Sale only. Laird Technologies makes no warranty, express,
statutory, and implied or by description, regarding the information set forth herein. Laird
Technologies reserves the right to change specifications at any time and without notice.

Laird Technologies products are intended for use in normal commercial and industrial
applications. Applications requiring unusual environmental requirements such as military,
medical life-support or life-sustaining equipment are specifically not recommended without
additional testing for such application.

Copyright © 2009 Laird Technologies, Inc. All rights reserved.
The information contained in this manual and the accompanying
software programs are copyrighted and all rights are reserved by
Laird Technologies, Inc. Laird Technologies, Inc. reserves the right to make
periodic modifications of this product without obligation to notify
any person or entity of such revision. Copying, duplicating, selling, or otherwise
distributing any part of this product without the prior consent of an authorized
representative of Laird Technologies, Inc. is prohibited.

All brands and product names in this publication are registered
trademarks or trademarks of their respective holders.

Limited Warranty, Disclaimer, Limitation of Liability

For a period of one (1) year from the date of purchase by the OEM customer, Laird Technologies
warrants the OEM transceiver against defects in materials and workmanship. Laird Technologies
will not honor this warranty (and this warranty will be automatically void) if there has been any (1)
tampering, signs of tampering; 2) repair or attempt to repair by anyone other than an Laird
Technologies authorized technician.

This warranty does not cover and Laird Technologies will not be liable for, any damage or failure
caused by misuse, abuse, acts of God, accidents, electrical irregularity, or other causes beyond
Laird Technologies’s control, or claim by other than the original purchaser.

In no event shall Laird Technologies be responsible or liable for any damages arising: From the
use of product; From the loss of use, revenue or profit of the product; or As a result of any event,
circumstance, action, or abuse beyond the control of Laird Technologies, whether such
damages be direct, indirect, consequential, special or otherwise and whether such damages are
incurred by the person to whom this warranty extends or third party.

If, after inspection, Laird Technologies determines that there is a defect, Laird Technologies will
repair or replace the OEM transceiver at their discretion. If the product is replaced, it may be a
new or refurbished product.

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DOCUMENT INFORMATION

Revision Description

Version 1.0.0 5/5/2009 – Initial Release Version

3/23/2006 3

TABLE OF CONTENTS

1.

OVERVIEW ......................................................................................................................................6

2. LT4424 SPECIFICATIONS.............................................................................................................7

3. SPECIFICATIONS...........................................................................................................................8

3.1 INTERFACE SIGNAL DEFINITIONS .........................................................................................................8

3.2 ELECTRICAL SPECIFICATIONS...............................................................................................................9

3.3 SYSTEM TIMING ...................................................................................................................................9

3.3.1 Serial Interface Data Rate...........................................................................................................9

3.3.2 Timing Diagrams.......................................................................................................................10

3.3.3 Maximum Overall System Throughput......................................................................................11

4. CONFIGURING THE LT4424......................................................................................................12

4.1 EEPROM PARAMETERS ....................................................................................................................12

4.2 CONFIGURING THE LT4424 ...............................................................................................................14

4.3 COMMAND REFERENCE ......................................................................................................................15

4.4 LT4424 AT COMMANDS....................................................................................................................16

4.4.1 Enter AT Command Mode.........................................................................................................16

4.4.2 Exit AT Command Mode............................................................................................................16

4.5 ON-THE-FLY CONTROL COMMANDS (CC COMMAND MODE) ............................................................17

4.5.1 Status Request............................................................................................................................17

4.5.2 Change Channel with Forced Acquisition Sync ........................................................................18

4.5.3 Server/Client..............................................................................................................................18

4.5.4 Broadcast Mode.........................................................................................................................18

4.5.5 Write Destination Address.........................................................................................................20

4.5.6 Read Destination Address..........................................................................................................20

4.5.7 EEPROM Byte Read..................................................................................................................20

4.5.8 EEPROM Byte Write.................................................................................................................20

4.5.9 Reset ..........................................................................................................................................21

5. THEORY OF OPERATION..........................................................................................................22

5.1 HARDWARE INTERFACE......................................................................................................................22

5.1.1 TXD (Transmit Data) and RXD (Receive Data) (pins 2 and 3 respectively).............................22

5.1.2 Hop Frame (pin 6).....................................................................................................................22

5.1.3 CTS Handshaking (pin 7)..........................................................................................................22

5.1.4 RTS Handshaking (pin 8)...........................................................................................................22

5.1.5 9600 Baud/Packet Frame (pin 12).............................................................................................23

5.1.6 RSSI (pin 13)..............................................................................................................................23

5.1.7 Wr_ENA(EEPROM Write Enable) (pin 14) ..............................................................................23

5.1.8 UP_RESET (pin 15)...................................................................................................................23

5.1.9 Command/Data (pin 17) ............................................................................................................23

5.1.10 In Range (pin 20).......................................................................................................................24

5.2 SOFTWARE PARAMETERS ...................................................................................................................25

5.2.1 RF Architecture (Server-Client/Peer-to-Peer) ..........................................................................25

5.2.2 RF Mode....................................................................................................................................25

5.2.3 Random Back Off.......................................................................................................................26

5.2.4 Duplex Mode .............................................................................................................................26

5.2.5 Interface Timeout/RF Packet Size..............................................................................................27

5.2.6 Serial Interface Baud Rate.........................................................................................................27

5.2.7 Auto Config................................................................................................................................28

6. DIMENSIONS.................................................................................................................................29

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ORDERING INFORMATION.......................................................................................................30

7.

7.1 PRODUCT PART NUMBERS..................................................................................................................30

7.2 DEVELOPER KIT PART NUMBERS .......................................................................................................30

8. REGULATORY INFORMATION................................................................................................31

8.1 AGENCY IDENTIFICATION NUMBERS ..................................................................................................31

8.2 APPROVED ANTENNA LIST.................................................................................................................31

8.3 FCC/IC REQUIREMENTS FOR MODULAR APPROVAL .........................................................................31

8.4 OEM EQUIPMENT LABELING REQUIREMENTS ...................................................................................32

8.5 ANTENNA REQUIREMENTS.................................................................................................................32

8.6 WARNINGS REQUIRED IN OEM MANUALS ........................................................................................32

Figures

Figure 1 – RSSI Voltage vs. Received Signal Strength.................................Error! Bookmark not defined.

Figure 2 – LT4424 with MMCX.................................................................................................................. 29

Tables

Table 1 – Pin Definitions................................................................................................................................ 8

Table 2 – DC Input Voltage Characteristics................................................................................................... 9

Table 3 – DC Output Voltage Characteristics................................................................................................ 9

Table 4 – Timing Parameters........................................................................................................................ 11

Table 5 – Maximum Overall System Throughputs...................................................................................... 11

Table 6 – EEPROM Parameters................................................................................................................... 12

Table 7 – Baud Rate..................................................................................................................................... 27

Table 8 – Auto Config Parameters............................................................................................................... 28

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LT4424 Features

 Simple 5V TTL level serial interface for fast integration
 Frequency Hopping Spread Spectrum for security and interference rejection
 Cost Efficient for high volume applications
 Low power consumption for battery powered implementations
 Small size for portable and enclosed applications
 Very Low latency and high throughput
 Industrial temperature (-40°C to 80°C)

1. Overview

The LT4424 is a member of Laird Technologies’s ConnexRF OEM transceiver family. It is designed for
integration into OEM systems operating under FCC part 15.247 regulations for the 2.4 GHz ISM band.

The LT4424 is a cost-effective, High performance, 2.4 GHz frequency hopping spread spectrum
transceiver. It provides an asynchronous TTL level serial interface for OEM Host communications.
Communications include both system and configuration data. The Host supplies system data for
transmission to other Host(s). Configuration data is stored in an on-board EEPROM. All frequency
hopping, synchronization, and RF system data transmission/reception is performed by the transceiver.

The LT4424 transceivers can be used as a direct serial cable replacement – requiring no special Host
software for operation. They also feature a number of On-the-Fly Control Commands providing the
OEM Host with a very versatile interface for any situation.

LT4424 transceivers operate in a Point-to-Point or Point-to-Multipoint, Client-Server or Peer-to-Peer
architecture. One transceiver is configured as a Server and there can be one or many Clients. To
establish synchronization between transceivers, the Server emits a beacon. Upon detecting a beacon,
a Client transceiver informs its Host and a RF link is established.

There are two data rates the OEM should be aware of:

• Serial Interface Data Rate – All transceivers can be configured to common PC serial port
baud rates from 110 bps to 288000 bps.

• Effective Data Transmission Rate – The LT4424 is a highly efficient, low-latency
transceiver. The RF baud rate of the LT4424 is fixed at 576 kbps and is independent of
the serial interface data rate.

This document contains information about the hardware and software interface between a Laird
Technologies LT4424 transceiver and an OEM Host. Information includes the theory of operation,
specifications, interface definition, configuration information and mechanical drawing.

The OEM is responsible for ensuring the final product meets all FCC and/or appropriate regulatory
agency requirements listed herein before selling any product.

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2. LT4424 Specifications

GENERAL

Interface 20 pin mini-connector
Serial Interface Data Rate PC baud rates from 110 bps to 288,000 bps
Power Consumption (typical) Duty Cycle (TX=Transmit; RX=Receive)

10%TX 50%TX 100%TX 100%RX Pwr-Down

LT4424-200: 115 mA 235 mA 385 mA 85 mA 15 mA
Channels (used to create independent networks) US/Canada: (200 mW) 16 Channels
Security One byte System ID
Interface Buffer Size Input/Output: 256 bytes each

RADIO

Frequency Band US/Canada (200mW): 2.402 – 2.478 GHz
Radio Type Frequency-Hopping Spread Spectrum
Output Power (conducted, no antenna) LT4424-200: 400mW typical
Effective Isotropic Radiated Power (EIRP with
5dBi gain antenna)
Voltage 5V nominal ±2%, ±50mV ripple
Sensitivity -90dBm typical
Range (based on dBi gain antenna) LT4424-200: Indoors to 500 ft., Outdoors to 15000 ft.

LT4424-200: 1000mW typical

ENVIRONMENTAL

Temperature (Operating) Industrial: -40°C to 80°C
Temperature (Storage) -50°C to 85°C
Humidity (non-condensing) 10% to 90%

PHYSICAL

Dimensions 1.65” x 2.65” x 0.20”
Antenna LT4424-200: MMCX Jack
Weight Less than 0.7 ounce

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3. Specifications

3.1 INTERFACE SIGNAL DEFINITIONS

The LT4424 has a simple interface that allows OEM Host communications with the transceiver. Table 1
– Pin Definitions, shows the connector pin numbers and associated functions. The I/O direction is with
regard to the transceiver. All I/O is 5VDC TTL level signals except for RSSI. All inputs are weakly pulled
High and may be left floating during normal operation.

Table 1 – Pin Definitions

Pin Type Signal Name Function

1 NC No Connect

2 O TXD Transmitted data out of the transceiver

3 I RXD Data input to the transceiver

4 NC No Connect

5 GND GND Signal Ground

6 O Hop Frame HOP FRAME – Active Low when the transceiver is hopping.

7 O CTS Clear to Send – Active Low when the transceiver is ready to accept data for transmission.

8 I RTS Request to Send – When enabled in EEPROM, active Low when the OEM Host is ready to

accept data from the transceiver. NOTE: Keeping RTS High for too long can cause data loss.

9 NC No Connect

10 PWR VCC 5V ± 2%, ± 50mV ripple

11 PWR VCC 5V ± 2%, ±50 mV ripple

12 I/O 9600_BAUD/

Packet Frame

13 O RSSI Received Signal Strength Indicator - An analog output giving a relative indication of received

14 I WR_ENA EEPROM Write Enable – When pulled logic Low, it allows the Host to write the on-board

15 I UP_RESET RESET – Controlled by the LT4424 for power-on reset if left unconnected. After a Stable power-

16 GND GND Signal Ground

17 I Command/Data When logic Low, transceiver interprets Host data as command data. When logic High,

18 NC No Connect

19 NC No Connect

20 O IN_RANGE In Range – Active Low when a Client radio is in range of a Server on same Channel with the same

9600_BAUD – When pulled logic Low before applying power or resetting the transceiver’s

serial interface is forced to a 9600, 8, N, 1 rate. To exit, transceiver must be reset or power-

cycled with 9600_Baud logic High.

*Note: 9600_BAUD should only be used to recover the radio from an unknown baud rate and

should not be used during normal operation.

Packet Frame – When programmed in EEPROM, Packet Frame will transition logic Low at the

start of a received RF packet and transition logic High at the completion of the packet.

signal strength while in Receive Mode.

EEPROM. Resetting the transceiver with this pin pulled Low may corrupt EEPROM data.

on (250ms) a 50us logic High pulse will reset the LT4424. Do not power up the transceiver

with this pin tied Low.

transceiver interprets Host data as transmit data.

System ID.

I = Input to the transceiver O = Output from the transceiver

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3.2 ELECTRICAL SPECIFICATIONS

Table 2 – DC Input Voltage Characteristics

Pin Type Name High Min. High Max. Low Min. Low Max. Unit

3 I RXD 0.2Vcc+0.9 Vcc+0.5 -0.5 0.2Vcc-0.1 V

8 I RTS 0.2Vcc+0.9 Vcc+0.5 -0.5 0.2Vcc-0.1 V
12 I 9600_Baud 0.2Vcc+0.9 Vcc+0.5 -0.5 0.2Vcc-0.1 V
14 I WR_ENA 0.7Vcc Vcc+1 -0.3 0.5 V
15 I UP_RESET 0.7Vcc Vcc+0.5 -0.5 0.2Vcc-0.1 V
17 I Command/Data 0.2Vcc+0.9 Vcc+0.5 -0.5 0.2Vcc-0.1 V

Table 3 – DC Output Voltage Characteristics

Pin Type Name High Min. Low Max. Unit

2 O TXD Vcc-0.7 @ -30μA 0.4 @ 1.6mA V
6 O Hop Frame Vcc-0.7 @ -30μA 0.4 @ 1.6mA V

7 O CTS Vcc-0.7 @ -30μA 0.4 @ 1.6mA V
12 O Packet Frame Vcc-0.7 @ -30μA 0.4 @ 1.6mA V
13 O RSSI See Figure 1 See Figure 1 V
20 O IN_RANGE Vcc-0.7 @ -30μA 0.4 @ 1.6mA V

3.3 SYSTEM TIMING

Care should be taken when selecting transceiver architecture as it can have serious effects on data
rates, latency timings, and Overall System Throughput. The importance of these three characteristics
will vary from system to system and should be a strong consideration when designing the system.

3.3.1 Serial Interface Data Rate

The Serial Interface Data Rate is programmable by the Host. This is the rate the Host and transceiver
communicate over the serial bus. Possible values range from 110 bps to 288,000 bps. The only

supported mode is asynchronous – 8-bit, No Parity, 1 Start Bit, and 1 Stop Bit

.

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3.3.2 Timing Diagrams

Addressed Acknowledge Mode with Interface Timeout:

Local_RXD

Local_RF_TXD

Remote_RF_TXD

Remote_TXD

Hop_Frame

Local_RXD

Local_RF_TXD

Remote_RF_TXD

Remote_TXD

Packet Data

Wait for Hop

RF Packet

RF Acknowledge

Rec eived Data

I nterface Timeout

Hop Period

Hop Time

Addressed Acknowledge Mode with No Interface Timeout:

Packet Data

Wait for Hop

RF Packet

RF Acknowledge

Received Data

Hop Period

Hop_Frame

Local_RXD

Local_RF_TXD

Remote_RF_TXD

Remote_TXD

Hop_Frame

Hop Time

Broadcast Acknowledge Mode with No Interface Timeout:

Packet Data

Wait for Hop

RF Packet

Received Data

Hop Period

Hop Time

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