CPMS SM ERROR from SIM900 Module Arduino

Hey guys,

Can anyone tell me what CPMS Error is?

I was using my sim chip successfully to make calls and send SMS.

I used to get a CPMS log in the serial monitor with something like:

CPMS = 79,100,39,50,100

Then I tried to add an entry to my sim phonebook using this code:


And now calls and sms dont work and I get this CPMS error:


The message you see with:

CPMS = 79,100,39,50,100

It's related to the preferred internal storage for SMS, which is the CPMS. It has the number of messages you have stored there, and the maximum capacity of the storage area. I think the error you see is because the Inbox and Sent folders are full, and you can't send nor receive any more messages until you delete them.

Sorry, at some point I cut off the error part. Its like this:


Im using the library from MarcoMartines at github here:

So I was wondering if this meant the CPMS was damaged and couldnt be accessed anymore but no, because even after buying the new sim, it worked, the same code.

The weird thing is that I did get this error again the first time i ran the code on the new sim. But then i ran it again and it worked perfectly and has since.

So Im not sure if its hardware or software. I wrote to simcom tech support and they werent very helpful.

Hi alfamaster,

Sorry it took a while to answer but I got sidetracked.

I tried AT+CMGL=“ALL” but I get ERROR.
I tried AT+CMGD=1 but I also get ERROR.

I checked the docs about the error and all I can find on many AT commands is a reference to:

“If error is related to ME functionality:

but surprisingly enough I cant find anything about ME functionality in the doc itself, what it means or how to fix it.