M66 modem shuts down when 4G sim card is used

IoT Modules GSM Module
1

Hello,

             I  have a pcb board with M66 R1.0  modem , when i use a 2G sim card  , the Modem can detect the sim card , its IMSI etc is  retrieved  through  AT  commands , but when i put a 4g sim card on it , modem automatically powers off within 1 or 2 minutes of powering on , when 4g sim card is removed and  a power on signal is applied again the Modem will stay on and answer AT commands, it answers all networks related commands like AT+COPS etc , i have tried putting the  4g sim in a 2g phone , making a call through it and then  putting it back in the board with no success .

i tried 2 different 4G sim card from Vodafone idea, and one from Reliance JIO.

ATI command to modem .
Quectel_Ltd
Quectel_M66
Revision: M66FAR01A12BT

2

Hi,
I’m sorry to reply you so late.
If your problem still exists, please contact us. You need to grab the log for us to analyze.Thanks.

3

What??? M66 is only 2G module.

4

HI ,

M66 is 2G module only and it can work with companies supporting 2G network such as Vodafone , airtel but it cant work with 4G only network such as reliance Jio who doesn’t have any 2G fallback .

5

M66 works with 4G sim card , in 2G mode if network has support for 2G , this problem is solved ,
higher value capacitor was required on Modem Power Pin , M66 apparently requires more capacitance on Power Pin ( > 470 uF) compared to similar modems from other vendors .