MC7354 Stops receiving SMS after 50 messages

I have a linux system where I want to use an MC7354 to receive SMS messages . I have an application that opens the port (/dev/ttyUSB2) and sets they MC7354 to receive messages and send to the terminal in PDU format (at+cmgf=0 and at+cnmi=1,2).

This works using other modems from other vendors. It works for the MC7354 for 50 messages, and then the MC7354 stops notifying the terminal that any messages are received. I have also seen this with the MC7304, so I believe there may be some sort of common issue with this modem family.

Has anyone seen this sort of problem or know of a way to fix it?

I updated to the latest firmware (Build4544-Approved-7354-EXE) but doesn’t seem to fix the problem.


i have similar problem here:

But with command at+cnmi=1,2 i am able to receive only MMS messages, not normal SMS. Normal SMS i can receive by at+cnmi=0,0 or at+cnmi=1,1.

I also faced the same issue with SMS on MC7304.This issue is observed only with at+cnmi=1,2 setting. with other settings it’s working fine.
I found that it’s because there is no eough memory.

The RAM can be release if you set up the testing with following steps.

  1. at+cmgf=1
  2. at+cnmi=1,2,0,2,0
  3. at+csms=1 //this command tell the ME that the TE shall send an ACK to the ME when a SMS is received.
  4. send the SMS to the modem.
  5. Each time the SMS is recived input at+cnma to the modem, at+cnma tells the ME the SMS has been received by the TE please release the buffer.

You can see my AT log in attachment :slight_smile:
ATlog.txt (3.86 KB)


I finally had time to get back to testing this. It appears that you found the solution. Sending an “at+cnma=0” allows the message to be acknowledged and I can continue to receive messages. I don’t think this should be required since I have “at+csms=0”, but it works so I can move on to other things. Thanks for your help and observations, this allows me to move past this problem.



after at+cnma i get +CMS ERROR: 340 on modem EM7305. I still have problem with stop receiving SMS after 50 received SMS. Only modem reset helps.

Are you following the steps mentioned in the attachment?
Can you share your AT log? Also module firmware?