The onboard two set power supply interface VCC5 5V power supply, VCC4 interface, 3.5--4.5V power supply, optional power on self starting (default) and control start.

The onboard SMA (default) and IPXmini antenna interface, SIM900A interface reserved reset.
The size of the module is 49*50, all the new and original device.
The computer can give early computer debugging USB module power supply, a very large amount of data under the condition of the recommended current more than 1A. Standby dozens of MA data can be set to provide dormancy, dormancy of 10MA low power. Support 2, mobile phone 3,4G card.
The serial port circuit: support for 3.3V single chip microcomputer. TTL serial port support
3.3 and 5V single chip microcomputer.
The SIM card circuit to increase the SMF05C ESD chip.
Antenna circuit: guarantee short and straight, so as to ensure the signal strength.
PCB display screen printing mark: each interface, convenient development two times, the SIM900/A hardware is completely follow the design when the design manual.
Two power supply interface: VCC5, 5V DC above 1A. Computer 5V power supply can be early computer USB. DC long data circuit over larger recommended 5V1A. VCC4, 3.5--4.5V power supply, ibid., suitable for lithium battery.
Control pin all leads.
A TTL level, compatible with 3.3V and 5V.
The two antenna interface, the default SMA straight head, connector for IPXmini antenna.
One way of speech interface, the way Mike interface.
The control interface of each pin description:
SIMR SIM900A RXD, TTL level, can not be directly connected to the 232 level
SIMT SIM900A TXD, TTL level, can not be directly connected to the 232 level
RST - SIM900A reset, active low
VCC_MCU when the SIM900A module and 5V TTL level communication, this pin is connected to DC 5V; when the level of communication of SIM900A and 3.3V TTL, this pin is connected to DC 3.3V.
VCC5----DC 5V input.
VCC4------DC3.5--4.5 input
Onboard Resources:
  • Serial port circuit(with protection)
  • Antenna interface circuit(SMA bend female port)
  • SIM card circuit(flip SIM slot)
  • 4*3.5 fixture hole 4pcs
  • SIM900A serial port output terminal
Package Includes:
  • 1 x SIM900A V3.8.2 kit
  • 1x Power Cable
  • 1x Antenna

  • Size:49mm x 47mm
  • Net Weight:28g
  • Weight: 38g 

Question & Answer

Total 31 questions

Q: He he he ! Very amusing Chi(E)nglish description ! Questioned by suntop, 09-Oct-2015

Q: When it's going to be available again. Questioned by btalha2, 23-Nov-2015

Within a week hopefully. Answered by A.R, 23-Nov-2015 09:33 AM

Q: When it's going to be available again. Questioned by btalha2, 23-Nov-2015

Q: Can this be connected to Arduino UNO/Mega using normal cables from RX and TX? Or do I need something more Questioned by RifatH, 07-Jan-2016

Q: is it one kind of breakout board for sim900? will this board work independently? Questioned by rabbyctg, 20-Jan-2016

Board is as it is shown in the pic. Please see the description well. whole package contents are mentioned. Answered by A.R, 20-Jan-2016 14:38 PM

Q: Can I connect it's rx, tx pin directly with microcontroller and use it. Please reply. Questioned by Sadique14, 30-Jan-2016

Q: এটাতে AA Battery Holder দিয়ে power দেয়ার জন্য কোন wire টা লাগবে? Questioned by Sadique14, 11-Feb-2016

Copper wire or male-male jumper must be soldered to the power pin. Answered by A.R, 11-Feb-2016 21:53 PM

male-male jumper wire খুজে পাচ্ছি না। please, link দেন। Answered by Sadique14, 12-Feb-2016 21:42 PM Answered by A.R, 14-Feb-2016 09:52 AM

Not available. Any way to use another wires? Answered by Sadique14, 20-Feb-2016 13:00 PM

Q: how can i connect TXD and RXD to microcontroller. Is there any way? I have to connect TXD to PD0 port of MC and RXD to PD1 port of MC Questioned by farzad, 14-Feb-2016

Those pins are all out here. You can easily connect them using jumpers. Answered by A.R, 14-Feb-2016 20:25 PM

Q: Can you give me data sheet of this device. Questioned by Milon_Sarkar, 04-Mar-2016

Q: How do i connect Rx and Tx to my computer. Questioned by smbakhtiar, 14-Mar-2016

With USB to serial converter. Answered by A.R, 15-Mar-2016 01:40 AM

Q: Thanks for the reply. So i have to purchase 1. SIM900A V4.0 Kit 2.USB to serial converter 3. Power supply. which work as gsm modem. Questioned by smbakhtiar, 15-Mar-2016

Please see this vid for more idea. You'll find more in the youtube. Answered by A.R, 15-Mar-2016 09:49 AM

Q: Thanks for the tutorial. But i am not use Arduino to connecte my pc , without Arduino uno is it possible to connect gsm module to my pc. Questioned by smbakhtiar, 15-Mar-2016

This question is also covered in the video a little bit. As we said earlier, you will need USB to serial converter. Answered by A.R, 15-Mar-2016 14:34 PM

Q: So if i buy SIM900A evaluation board then what step will follow to complete the gsm modem construction. I think i need following, Please help me. 1. SIM900A evaluation board 2. usb to serial converter. 3. power supply is any think else or if you have any other product which cover my requirement please tell i will purchase it. So what i need i have to connect gsm modem to my pc for simulation testing , than my MC. Please help me Questioned by smbakhtiar, 15-Mar-2016

As far as we are concerned , to connect it with PC you will need USB to serial converter and USB cable, just like any other GSM module shown in our GSM tutorials. After adding a valid SIM, it must work fine. However, you are requested to see the video we gave earlier and visit the sites shown in that video to find out the proper pinout , power supply etc. For connecting it with microcontroller and arduino, you do not need any converter. Just make direct connection as shown in the video. Answered by A.R, 16-Mar-2016 10:25 AM

Q: Thanks for reply. I congratulate you. I want complete gsm modem. Where i can plug the cable play with at command just like other modem. Do you have this kind of product ready made. If so i will purchase it. Questioned by smbakhtiar, 16-Mar-2016

Oh. No. Sorry. We sell components actually. Not full furnished products. Answered by A.R, 16-Mar-2016 12:37 PM

Q: Thanks. If i buy SIM900 Development Board then my it will solved what i want. What i want is connect SIM900 Development Board to my pc using converter and PC will detected the device. Then i play it using AT command. Please suggest me. Questioned by smbakhtiar, 16-Mar-2016

Yes. Possible. Answered by A.R, 16-Mar-2016 13:05 PM

Q: If i buy SIM900 Development Board . What additional component will need to buy. Questioned by smbakhtiar, 16-Mar-2016

Which product? This one or another? Answered by A.R, 16-Mar-2016 13:57 PM

Q: Not this one. this one SIM900 Development Board Questioned by smbakhtiar, 16-Mar-2016

If you are talking about this ( then please at first see all the documents in the documents section. For any further info contact Mr. Rezwanul Islam at [email protected] .He made that board. We are just selling his device. Answered by A.R, 16-Mar-2016 14:30 PM

Q: jumper takontar sathe konta short a rakhte hoy ektu janale khub upokar hoy Questioned by Skylarkk, 09-Apr-2016

Please follow the description of this product. Answered by FAHIM_REAZA, 09-Apr-2016 17:37 PM

Q: Dear Concern, I purchase SIM900A V4.0 Kit just 11/04/2016 . but i am unable to connect it to my pc . where i am using usb to serial converter. can you help me to find out that which pin is connected to which pin . Because i can not find any direction on description page. Please help me. Questioned by smbakhtiar, 12-Apr-2016

Our "Technical Team" has already contacted with you and we think your problem has been solved. Thanks for with us. Answered by FAHIM_REAZA, 19-Apr-2016 12:33 PM

Q: Yes, He solved my problem. He performance is excellent.And also he is good person.I thanks to him also TECHSHOP. Questioned by smbakhtiar, 19-Apr-2016

Q: i JUST HAVE BROUGHT IT. WHERE IS TX AND RX. PLEASE ME? Questioned by aminur99rahman, 22-Jul-2016

Please follow the 6-pin yellow color male connector. The middle two pin RX and TX. Answered by FAHIM_REAZA, 23-Jul-2016 11:28 AM

Q: You guys didn't provide the antenna. :/ Questioned by swapnilsayansaha, 24-Aug-2016

The package included with an antenna and also a power connecting cable. Answered by FAHIM_REAZA, 28-Aug-2016 09:12 AM

Q: Can it be used with arduino to make http requests? If yes can you please tell me how? Questioned by niloy369, 20-Dec-2016

Please see the AT command list of SIM900A. Answered by A.R, 21-Dec-2016 10:23 AM

Q: I have purchased SIM900A module. I supplied 5V,2A power supply and inserted GP sim card. but the led is blinking fast. That means it is not getting the network. Could you please help me to solve this problem? Questioned by shamsulalam53, 09-Mar-2017

What is your order id? Answered by A.R, 09-Mar-2017 10:25 AM

Order Information #134675 Answered by shamsulalam53, 10-Mar-2017 10:16 AM

Please send the product back with a copy of your invoice. We must check that first. Answered by A.R, 11-Mar-2017 09:48 AM

Q: Atate Audio output kora jabe ki vabe ? Questioned by Asif3883, 01-Jun-2017

Not possible. Answered by A.R, 01-Jun-2017 10:09 AM

Q: kit ta te 3.7 volt ar battery die power dibo ki vabe ? Questioned by Asif3883, 05-Jun-2017

You must solder male header with battery. Answered by A.R, 07-Jun-2017 11:40 AM

Q: Does it support 3G or 4G Questioned by nargisakhter, 05-May-2018

Sorry. This is not for video call. Only sms, phone related works. Answered by A.R, 06-May-2018 11:00 AM

Q: Is this have rx and tx socket? Questioned by Shovonmondol0055, 22-Sep-2018

Rx, Tx pinout given. Please see here: Answered by A.R, 23-Sep-2018 09:46 AM

Q: Can I give 3.3 volt in it? Questioned by Shovonmondol0055, 22-Sep-2018

5V. Answered by A.R, 23-Sep-2018 09:42 AM

Q: Power status light is not blinking. It keeps continuouslu glowing not blinking. Is it power supply issue or other problem..plz guide. Questioned by Salahuddinsami, 24-Aug-2020

That is not a problem at all! POwer LED is supposed to glow and NETWORK LED is supposed to blink. KIndly see all the tutorials given in the 'documents' section. Answered by A.R, 25-Aug-2020 10:53 AM

Q: Which SIM card I am supposed to use. Grameen Phone does not work Questioned by faizullah1190, 16-Jan-2021

SIM900A Kit works fine with all registered networks in Bangladesh. Please check the device antenna connection and the network availability. If you are facing any further problems, please don’t hesitate to contact us (Customer Care: 09 678 110 110). Answered by FAHIM_REAZA, 17-Jan-2021 15:35 PM

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