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
Road safety comes first! Do not use a hand-held cellular terminal or mobile when driving a
vehicle, unless it is securely mounted in a holder for hands free operation. Before making a
call with a hand-held terminal or mobile, park the vehicle.
GSM cellular terminals or mobiles operate over radio frequency signals and cellular networks
and cannot be guaranteed to connect in all conditions, for example no mobile fee or a invalid
SIM card. While you are in this condition and need emergent help, Please Remember using
emergency calls. In order to make or receive calls, the cellular terminal or mobile must be
switched on and in a service area with adequate cellular signal strength.
Some networks do not allow for emergency call if certain network services or phone features are
in use (e.g. lock functions, fixed dialing etc.). You may
have to deactivate those features before you can make an emergency call.
Also, some networks require that a valid SIM card be properly inserted in the cellular terminal
or mobile.
SIM900B_HD_V1.03 24.06.2010
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