Ai Thinker A9 GPRS Series Module can be used in a wide range of IoT applications and is ideal for IoT applications for home automation, industrial wireless control, wearable electronics, wireless location sensing devices, wireless location system signals, and other IoT applications. The A9 is a complete quad-band GSM / GPRS module in a compact design SMD package. Its stable performance, the appearance of compact, cost-effective, could meet the diverse needs of customers. Features: Supports GSM/ GPRS frequency: 800/ 900/ 1800/ 1900 MHz. Supports voice calls and SMS messages. The data rate is 85.6 Kbps Supports firmware upgrade via serial port Support PBCCH Supports 3 serial ports, one download serial port, one AT command port. Working temperature: -30 -80 Working voltage: 3.5v 4.2v (its best to power by 4v) Power voltage: >3.5 Volts Low power consumption: Sensitivity GPIO level: 2.8 volts Package includes: 1 x Ai Thinker A9 GPRS Series Module Additional information Model Name A9 Package SMD54 Frenquency 850/900/1800/1900MHz GPRS Multi-slot Class 12 GPRS Mobile Station Class B Power supply 3.5~4.2V typical value 4.0V Current 1.14mA@DRX=5 1.03mA@DRX=9 AT command 3GPP TS 27.007, 27.005 GPRS Class 12 Max 85.6kbps (Up & Down) Coding scheme CS 1,2, 3, 4 PBCCH support SIM Card 1.8V/3V UART 3pcs (including firmware upgrade serial port)baud rate support 2400~1843200bps, default115200bps Antenna Pad Communication Interface I2C,USB,UART,SDMMC,GPIO,ADC Working Temperature -20C ~ 75C Length (mm) 19.2 Width (mm) 18 Height (mm) 2.5 Weight (gm) 3 * Product Images are shown for illustrative purposes only and may differ from actual product.