How to answer phone call using gsm module and computer

How to answer  phone call using gsm module and computer:

In this article you will learn how to answer to a phone call using gsm module and computer. To answer a phone call your gsm module should be interfaced with speaker and head phone. You can purchase Mikro C gsm development board. It have all the things connected with it, you need to answer a phone call using gsm module. I have already posted 4 articles related to gsm interfacing with computer, microcontrollers and projects based on GSM. You can also check following articles :

There are many gsm modules are available in market. But I recommend you to use latest gsm module. I will be dealing with SIM900D gsm module in this article. SIM900D gsm module have two microphone and two speaker connections. You can either interface speakers and headphones with gsm module or you can buy read to use gsm development board. Gsm development board should have speaker and headphone interfaced with it like Mikro C gsm development board. Microphone will be used to communicate your voice to end-user and speaker will be used to listen to end-user. Mikro C gsm board also have amplifiers attach with microphone and speaker to increase or decrease level of voice.




How to interface gsm module with computer :

First you need to interface gsm module with computer to make settings of gsm module. I have already explained in how to make call using gsm module article about how to connect gsm module with computer. Basic circuit diagram to connect gsm module is shown in figure below:

gsm module interfacing with computer

how to make call using gsm module

In diagram label 2 is gsm module which is connected with max232 voltage level converter IC and label 1 should be connected with com port of your computer. Max232 is voltage level converter IC. Gsm module work on 5 volt logic and computer serial port work on 12 volt logic. Therefore we need to used MAX232 voltage level converter IC to make them compatible with each other for serial communication. After connecting gsm module with computer follow following instruction to answer to a phone call.

How to answer phone call using gsm module :

After connecting gsm module, open hyper terminal of your windows for serial communication with gsm module. If your system don’t have gsm module you can download it from any website related to software’s. After opening hyper terminal, write following commands in hyper terminal.

  • “AT+CHFA = 1” this command is used to select Audio channel of gsm module. 1 mean selection of channel 1 of gsm module.
  • “AT+CMIC = 1, 0 ” It is used to select gain of microphones.

After that whenever any one call on your number which you used in gsm module sim jacket. You will see a message ring on hyper terminal and also speaker will give a sound of ring. Now to answer phone call using gsm module, Type following commands in hyper terminal.




  • ATA type this command in hyper terminal and hit enter. Now you are ready to talk with the person who called you.
  • ATH if you want to end call at any time, you can type this command in hyper terminal and hit enter. call will be terminated.
  • AT+CLCC you can check the number of caller using this command.

I hope after reading this article you will be able to answer phone call using gsm module and computer. Thanks for coming to our blog. Do share with friends. This is what you can do for me in return 🙂

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