User's Manual
Table Of Contents
- Contents
- Version history
- 1 Introduction
- 2 SIM900B Overview
- 3 Application Interface
- 3.1 SIM900B Pin Description
- 3.2 Operating Modes
- 3.3 Power Supply
- 3.4 Power Up and Power Down Scenarios
- 3.5 Power Saving
- 3.6 Summary of State Transitions (except SLEEP mode)
- 3.7 RTC Backup
- 3.8 Serial Interfaces
- 3.9 Audio Interfaces
- 3.10 Buzzer
- 3.11 SIM Card Interface
- 3.12 LCD Display Interface
- 3.13 Keypad Interface
- 3.14 ADC
- 3.15 Behaviors of the RI
- 3.16 Network Status Indication
- 3.17 General Purpose Input Output (GPIO)
- 4 Antenna Interface
- 5 Electrical, Reliability and Radio Characteristics
- 6 Mechanics
SIM900B Hardware Design
(1) The SIM900B does work, but deviations from the GSM specification may occur.
Table
4: Coding schemes and maximum net data rates over air interface
Coding scheme 1 Timeslot 2 Timeslot 4 Timeslot
CS-1: 9.05kbps 18.1kbps 36.2kbps
CS-2: 13.4kbps 26.8kbps 53.6kbps
CS-3: 15.6kbps 31.2kbps 62.4kbps
CS-4: 21.4kbps 42.8kbps 85.6kbps
2.2 SIM900B Functional Diagram
The following figure shows a functional diagram of the SIM900B and illustrates the mainly functional part:
z The GSM baseband engine
z Flash and SRAM
z The GSM radio frequency part
z The antenna interface
z The board-to-board interface
z The Other interfaces
SIM900B_HD_V1.03 24.06.2010
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