Module:SIM900A                                                       
Network:GSM/GPRS (2G)                                                  
Frequency Bands:GSM 900 MHz, DCS 1800 MHz   
GPRS Class:Class 10                                          
Data Speed:Up to 85.6 kbps (download), 42.8 kbps (upload)
SMS:Text mode and PDU mode                                 
Voice Calls:Supported  
USSD:Supported   
TCP/IP Stack:Built-in 
Protocols:TCP, UDP, HTTP, FTP, PPP  
Interface:UART (Serial TX/RX)                                      
AT Commands: GSM 07.07, GSM 07.05, SIMCom Enhanced AT Commands
Baud Rate:1200–115200 bps (default 9600 bps) 
SIM Card:1.8V/3V SIM                      
Supply Voltage (Module):3.2V–4.8V (typical 4.0V)  
Supply Voltage (Development Board):Usually 5V DC input                                            
Current Consumption:Sleep: ~1.5 mA; Average transmit: ~250 mA; Peak transmit: up to 2 A 
Operating Temperature:-40°C to +85°C                                                     
Dimensions (Module):24 × 24 × 3 mm   
Antenna:External GSM antenna (typically SMA or IPEX connector):([y-ic.com][1])