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
Table
20: Working state of the NETLIGHT
State SIM900B function
Off SIM900B is not running
64ms On/ 800ms Off SIM900B does not find the network
64ms On/ 3000ms Off SIM900B find the network
64ms On/ 300ms Off GPRS communication
The reference circuit is shown as the following figure:
300R
4.7K
47K
MODULE
NETLIGHT
VBAT
Figure 31: Reference circuit of NETLIGHT
SIM900B_HD_V1.03 24.06.2010
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