Arduino Sim900 shield; receiving sms text in hex????

I have a remote control project using the Nano and Sim900 shield.
Working fine when sending sms but when receiving sms something odd is happening:

This is the output from serial monitor:

[12:24:45:311] +CMT: "+47xxxxxxxx","","16/11/13,12:24:41+04"␍␊
[12:24:45:327] 000A00480076006F00720020007600610072006D00740020006500720020006400650074D83DDE00␍␊

Converting the hex string gives me the following:


The original message sent is (in norwegian);

Hvor varmt er det:-)

Init of Sim900 shileld is:

[12:23:17:782] OK␍␊
[12:23:17:782] AT+CMGF=1␍␍␊
[12:23:17:782] OK␍␊
[12:23:17:799] AT+CNMI=2,2,0,0,0␍␍␊
[12:23:17:799] OK␍␊

Anybody have a clue??????


Show us the line used to print the SMS to the serial monitor. It looks like your reading a character at a time and printing it (including the null terminator) as HEX.


These are the lines used sending it to monitor:

if(SIM900.available() >0)
{; //Get the character from the cellular serial port.
Serial.print(incoming_char); //Print the incoming character to the terminal.

I have also tried the most of other solutions amnong Serial.write(incoming_char);
and making even buffers ......



Hi Kjartan,

I'm having difficulty finding the SIM900 library your using so can you please post details of where the library came from and maybe post the code (or a working part of it) that shows the SMS receive problem.

Hi kjartani

It may be better to some of the control has been Form (controlpPanel), in real time. Web Form, Android or Windows?
I am interested in this topic, my projects are also associated with the remote control.

Hi Revi.
Im not using Sim900 library.
The commands sent to the Sim900 are the ATs.commands, and I use the SoftwareSerial for communication.
But I will explore the Sim900 library.....