SIM7600CE-T 'Garbled' received messages

userHead Zachary.Jones 2022-12-19 06:45:21 836 Views2 Replies

I'm having issues in the accuracy of SMS messages received. Quite often either the wrong characters are read/found or character mystery marks are displayed. Below is a example of my testing. I have changed some of the phone number numbers because I don't want to post my phone number. This is only a issue with receiving text messages and initialization.

+CMT: #+4420408320a9","","22/12/19,10:57:40+52"
Testing 123

+CMT: "+442040832019","","22/12/19,10:57:57+52"
TESVING 321

+CMT: "+462040832019"\"","22/12/18,10:58:09+51"
123 testing

+CMT: "+442040832019","",B22/12/19,10:58:25+52"
321 TESTING

)CMT: "+442040832019","","22/12O19,10:58:45+52"
TESTING 567

As seen characters are randomly 'garbled' in the date, system characters displayed and messages. I don't get this problem with the SIM900 chip, and I've tried multiple methods of programming using two SIM7600CE-T 4G(LTE) controllers to insure its not just a outlier in hardware. The programming for this test displayed is the example code provided in the tutorial using a 115200 baud rate. My conclusions are that this is either caused from some strange serial communication problem, maybe the aerial isn't the right size (using the aerial provided with the chip), maybe the cellular frequency's are incompatible in New Zealand on 900Mhz and 1800Mhz, or the SIM7600CE-T 4G(LTE) chips are just not accurate in cellular communication. I would like to know the cause of this problem and how to fix it.

 

DF tutorial: https://wiki.dfrobot.com/SIM7600CE-T_4G(LTE)_Shield_V1.0_SKU_TEL0124#target_5

 

 

Thanks for the help!

2023-01-02 07:39:23

Hi Zachary,

 

Im a complete newbie and just got the sim7600ce before Christmas. I followed the details in the link https://wiki.dfrobot.com/SIM7600CE-T_4G(LTE)_Shield_V1.0_SKU_TEL0124#target_5 and downloaded the code but same  issues as you. Any chance you could  forward me a copy of your sketch with the changes please.

 

Also thanks for posting as I have been very frustrated the last few days.

userHeadPic mejtom
2022-12-27 15:26:50

solved 

-The chips default buad rate is too fast and needs to be set to a lower rate by setting the Arduino to 115200, then setting the chip to a rate such as 19200, then setting the Arduino's boad rate to 19200. Use following code for the fix. 

 

GSM.begin(115200); // for GSM shield 

 

GSM.print("AT+IPR=19200\r"); //for SIM7600 

 

Serial.begin(19200); 

 

GSM.begin(19200);

userHeadPic Zachary.Jones