Does anyone have in depth knowledge of the Arduino GSM Shield2 and/or SIM's

Hello All, I have a strange issue with SIM's from a particular operator;

all other SIM's I have used work fine in the GSM Shield, all sketches work fine, everything is in order until I use one particular Operators SIM's,

the SIM is roaming, I can see it connects to the correct network, I can hear paging and I can even hear inbound ringing but I do not get the same output in the "receive call" sketch, I do not get the waiting notification or the incoming number, the call does not hang as it should according to the sketch.

If I run an AT commands sketch I can see the incoming call ringing as its notified in the serial monitor

I know this is not an issue with the shield or sketch so I would like to know if anyone has any idea about SIM's in the shield

NB if the SIM is placed in an iPhone it works as it should so it must be how the SIM interfaces with the shield...

any help would be greatly appreciated

Dan

oh and I can add that I can only get the SIM to connect or at least partially output the "receive calls" sketch by inputting a reset by setting PIN7 to high momentarily, this I do not have to do for any other SIM (I have tried many from multiple operators both roaming and local SIM's)

I am using ETSI TS 102 221 to try to understand SIM's...

Yo
Can you please tell me what company SIM you are using? Because I am using TMOBILE sim here in the USA and mine is not working. Like I get a blink every second instead of every three secodns

Hi, I didnt look at the LED's just the serial output so cannot help you there

I am using a SIM from Kyrgyzstan so I doubt its the same issue you are having as I would expect a SIM from Tmobile US to be of reasonable quality and configured correctly

Dan