SIM800 vs SIM900: What is the difference/Similarities?

Hi tech freeks, this post is to answer an important question from our customers, about is the difference in SIM800 and SIm900 GSM Modules. The short answer is “there is not much difference…”. Long answer is described below.


AT command is 99 percent same.

Notable difference is that the SIM800 module has support for Blutooth. So the AT command is extended for Bluetooth/FM functionality.

Similarities in AT commands




Call a number



Hang up a call



Message send



Message read



Message delete



This means most of the Arduino Libraries newer mind using SIM800 or SIM900 based GSM Chip.

Difference in hardware design?

  • SIM800,SIM800C modem operates from 3.4V to 4.4V supply range (Reduced operating range  !)
  • SIM900, SIM900A modules operate from 3.2V to 4.8V supply range.
  • SIM800 is having a Pin to connect with Bluetooth Antenna

Apart from these differences the hardware design is almost similar. The same hardware circuit can be used for the SIM IC if the generated supply is within 3.4V to 4.4V for both types..

Why you should switch to SIM800.?

  • SIM800 is the newly released chip, which is an alternate to SIM900 from SIMCOM

  • SIM900 is under obsolescence.

  • SIM800 is having better signal reception capability.

  • SIM800 has more functionality like Bluetooth 3.0

  • Less costly than SIM900 ICs

  • SIMCOM nolonger releases the firmware updates to SIM900.

Where to buy the hardwares:

We supply SIM800 based USB, RS232, TTL modules for easy prototyping.

Purchase Links:–380–266–260

All the existing blogs and sample codes are fully compatible with SIM800, even if SIM900 is mentioned in the blogs.

Hardware Interfacing blog posts:

For example try out the code in the below link from out GitHub page. You can see the same code works for both SIM800 and SIM900 modules.

Sample code:

Arduino Forum about the topic:

Other Links:


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