SIM900A module\SMS\development board\GSM\GPRS\STM32\wireless data transmission super TC35i Sim900a Sim900 Mini V4.0 Wireless Data Transmission Module Gsm Gprs Board Kit W/antenna C83

1. Introduction to SIM900A Module

        The power supply requirements of this module: 5V power supply, thecomputerUSB power supplycan meet the requirements in theinitial stage ofcomputerdebugging.Because we added a large capacitor of 1000UF.Long-term data transmission requires a large amount of power. It is recommended to use a DC above 1A, and the TTL level serial port is adaptively compatible with 3.3V and 5V microcontrollers.It can be directly connected to the microcontroller.The standby mode is around 80MA, and the sleep state can be set to around 10MA for low power consumption.Both USB--232 and USB--TTL can be used for computer debugging, depending on each person's accessories.Support SMS, data, MMS, Internet, etc.The reset pin is led out to realize unattended remote reset on site, with DTMF function to realize remote control function.The biggest advantage of the module is that it retains 232 ports, and can monitor the execution of 51 low-end single-chip microcomputers and module instructions during learning or development, which can find out the cause faster and save development and learning time. [Support 2,3,4G mobile phone card 】.This is the default.

       The SIM900A module is also sold with a DC power supply of 3.5-4.5V or more than 1.5A, suitable for 3.7V lithium battery power supply. Need to contact customer service. The TTL level of this module is compatible with the 3.3V system, and the 5VTTL system needs to pass the 232 control module. 

Advantages of this module: 

• Serial port circuit: TVS and magnetic bead protection devices are used to protect the board, so that the board will not be damaged by surges and high voltages.
• SIM card circuit: Add SMF05C electrostatic discharge chip.
• Antenna circuit: Keep it short and straight, so as to ensure the signal strength.
• PCB display: Each interface is marked by silkscreen, which is convenient for secondary development, and the design completely follows the SIM900A hardware design manual.
• One way 5V power supply interface: We have done protection, even if it is reversed, it will not burn the board. The computer USB power supply is sufficient for the initial debugging of the computer ; long-term data transmission requires a large amount of electricity, and we recommend a DC above 1A.
• One TTL interface: supports 3.3V single-chip microcomputer and 5V single-chip microcomputer. In other words, it supports 51 types of 5V single-chip microcomputers and STM32 single-chip microcomputers.
• Two antenna interfaces: SMA antenna interface, IPX MINI antenna interface (no welding by default).
• One 232 level interface: In other words, you can directly connect the module to the computer through a 232---USB serial cable. It can also be connected to a computer via USB-TTL, depending on personal accessories. No need to spend more money to buy accessories. This is the biggest difference from other sellers.