GPRS/GSM Study Notes (i)--gprs/gsm introduction

GSM 's English is globalsys-temformobilecommunica-tion, the global mobile communication system, proposed by the European Standardization Commission. GSM system has good anti-theft copy ability, large network capacity, rich number resources, clear calls, strong stability is not easy to be disturbed, information sensitive, call dead-ends less, mobile phone low power consumption characteristics.

GPRS is the abbreviation of Generalpacketradioservice, Chinese is the general wireless packet business. It has the advantages of real-time online, metered, fast login, high-speed transmission and easy switching.
The use of GPRS Internet is different from WAP, with WAP Internet is like at home in the Internet, first "dial-up connection", after the internet can not use the telephone line, but with GPRS download data and calls can be carried out , that is, the call continued to use GSM, and the transmission of data can use GPRS.
Simple understanding:GSM is a mobile phone voice network, is the telephone to send text messages network, and GPRS is to use mobile phone to send and receive data online.


SIM300 Module appearance

The SIM300 is a three-band Gsm/gprs module that operates on a global scale of egsm 900MHz, DCS 1800MHz, PCS 1900MHz Three frequencies, provides up to 10 GPRS multi-channel types, and supports CS-1, CS-2, CS-3 and CS-4 four kinds of GPRS coding schemes.

SIM300 internal function modules are:
Keyboard and SPI type LCD interface for users to develop their own application equipment.
Two serial ports with debug and data output to help developers develop products more easily.
Dual audio channels with two mic inputs and two mic outputs for easy configuration of the operating mode at the AT command.

The SIM300 has two RF antenna interfaces: One is an antenna connector and one is an antenna solder joint .  The antenna connector model is Murata mm9329-2700, which allows the user to weld the antenna itself through the antenna solder joints. The SIM300 supports voltage range 3.4~4.5v. The SIM300 has a low power design and consumes only 2.5mA of current in sleep mode. The SIM300 integrates the TCP/IP protocol stack and extends the TCP/IP at directive, making it particularly easy and convenient for users to develop data transmission devices using this module.

SIM300 all IO ports

Functional Features:
Size: 7.5* 6cm
Product chip: SIM300
Interface: Standard 2.54MM double-row pin, all IO ports.
Power supply Mode: Integrated 4V power conversion chip. Direct 5V power supply
led Indicator:GSM Signal Indicator
Antenna interface: Standard GSM antenna
Interface: SIM card holder, headphone microphone interface.