The power supply requirement of this module: 5V power supply, the computer USB power supply can meet the requirements in the initial stage of computer debugging. Because we added a big 1000UF capacitor. Long-term data transmission power consumption is recommended more than 1A DC, TTL level serial adaptive compatible with 3.3V and 5V microcontroller.

1. Introduction to SIM900A module

The power supply requirement of this module: 5V power supply, the computer USB power supply can meet the requirements in the initial stage of computer debugging. Because we added a big 1000UF capacitor. Long-term data transmission power consumption is recommended more than 1A DC, TTL level serial adaptive compatible with 3.3V and 5V microcontroller. Can be directly connected to the single chip computer. Standby at about 80MA, you can set the sleep state at about 10MA low power consumption. Computer debugging USB-232 and USB-TTL are available, depending on each person's accessories. Support SMS, data, MMS, Internet, etc. Reset pin extraction, can achieve unattended remote reset, with DTMF function to achieve remote control function. The advantage of the module is that it retains 232 ports, which can monitor the execution of 51 low-end single-chip computers and module instructions when learning or developing, which can find out the reasons faster and save the time of development and learning.[Support 2,3,4G mobile phone card].

The TTL level of this module is compatible with 3.3V system, and the 5VTTL system needs to pass the 232 control module.

Advantages of this module:

Serial circuit: TVS and magnetic bead protection devices are used to protect the board, so that the board will not be harmed by surge and high voltage.
SIM card circuit: Add SMF05C static release chip.
Antenna circuit: Ensure that it is short and straight, so as to ensure signal strength.
PCB display: Each interface is screened to facilitate secondary development, and the design fully follows SIM900A hardware design manual.
One 5V power supply interface: we have made protection, even if the connection is reversed, it will not burn the board. Computer initial debugging computer USB power supply can be; Long time data transmission power consumption is larger we recommend more than 1A DC.
One TTL interface: Support 3.3V single chip microcomputer and 5V single chip microcomputer. That is to say, it supports class 51 5V microcontrollers and STM32 microcontrollers.
Two antenna ports: SMA antenna port, IPX MINI antenna port (not welded by default).
One 232 level interface: This means that you can connect the module directly to the computer via a 232- USB serial cable. You can also use USB-TTL to connect to your computer, depending on your accessories. You don't need to spend more money on accessories that's the difference from other sellers.
Description of the SIM900A module:

Computer control module method:

In a word, it is to control the module by sending instructions (AT instructions) through the serial port. The following describes the two common ways to control the SIM900A module:
Kinds: Through CP2102 USB to TTL module this shop has sales, computer debugging SIM900A module.

The second: Connect the module to the computer through the USB-232 serial port line, and then access the 5V power supply.

Default shipping list
sim900a module *1
GSM module antenna *1
Module power cable *1,