TABLE OF CONTENTS
1. INTRODUCTION ...................................................................................................................................................1
1.1 Why Spread Spectrum? ...................................................................................................................................1
1.2 Frequency Hopping vs. Direct Sequence ........................................................................................................2
2. RADIO OPERATION .............................................................................................................................................4
2.1. Synchronization and Registration ..................................................................................................................4
2.2. Data Transmission .........................................................................................................................................5
2.2.1. Point-to-Point .......................................................................................................................................5
2.2.2. Point-to-Multipoint ................................................................................................................................6
2.2.3. TDMA Mode .........................................................................................................................................6
2.2.4. Full Duplex Communication .................................................................................................................8
2.2.5. Error-free Packet Transmission Using ARQ ........................................................................................8
2.3. Modes of Operation ........................................................................................................................................9
2.3.1. Control and Data Modes ......................................................................................................................9
2.3.2. Sleep Mode ..........................................................................................................................................9
2.3.3. Low Power Mode and Duty Cycling .................................................................................................. 10
2.3.4. RF Flow Control Mode ....................................................................................................................... 10
3. PROTOCOL MODES ......................................................................................................................................... 11
3.1. Packet Formats ........................................................................................................................................... 13
3.1.1. Data Packet ...................................................................................................................................... 13
3.1.3. Connect Packet ................................................................................................................................. 14
3.1.4. Disconnect Packet (base only, receive only) ................................................................................... 14
4. MODEM INTERFACE ........................................................................................................................................ 15
4.1. Interfacing to 5 Volt Systems ...................................................................................................................... 16
4.2 Evaluation Unit and OEM Module Differences ............................................................................................ 16
4.3 Three Wire Operation .................................................................................................................................. 16
4.4 Power-On Reset Requirements .................................................................................................................. 17
5. MODEM COMMANDS ....................................................................................................................................... 18
5.1. Serial Commands ........................................................................................................................................ 18
5.2. Network Commands .................................................................................................................................... 19
5.3. Protocol Commands .................................................................................................................................... 21
5.4. Status Commands ....................................................................................................................................... 24
5.5. Memory Commands .................................................................................................................................... 25
5.6. Modem Command Summary ...................................................................................................................... 26
6. WIT2420 DEVELOPER’S KIT ............................................................................................................................ 27
6.1. COM24/WinCOM24 .................................................................................................................................... 27
6.2. Demonstration Procedure ........................................................................................................................... 28
6.3. Troubleshooting .......................................................................................................................................... 29
7. APPENDICES ..................................................................................................................................................... 31
7.1. Technical Specifications .............................................................................................................................. 31
7.1.1 Ordering Information .......................................................................................................................... 31
7.1.2. Power Specifications ........................................................................................................................ 31
7.1.3. RF Specifications .............................................................................................................................. 31
7.1.4. Mechanical Specifications ................................................................................................................ 31
7.2. Serial Connector Pinouts ............................................................................................................................ 32
7.3. Approved Antennas ..................................................................................................................................... 32
7.4. Technical Support ....................................................................................................................................... 32
7.5. Reference Design ....................................................................................................................................... 33
7.6. Mechanical Drawing ...................................................................................... Error! Bookmark not defined.
7.7. Warranty ........................................................................................................ Error! Bookmark not defined.
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