Verizon LTE CAT-1 Radio Unable to Store SMS
MultiTech's LVW3 and LNA3 CAT-1 cellular radio products are incapable of storing SMS to memory for radio firmware prior to 20.00.014. Even if SM or ME have storage indexes available no messages will get stored. Applications must be written to set 2nd and 4th CNMI values to 2 and process messages in real time. Any messages received when an application is not watching for them will be accepted by the module and discarded. Telit has provided a beta firmware 20.00.014 which has resolved the issue, but there has not been any carrier approval for that version yet. When a SIM has storage, the response to AT+CPMS is like the following. This response indicates there are 15 total memory areas available in SM (SIM) of which 0 are being used to store messages: AT+CPMS? +CPMS: "SM",0,15,"SM",0,15,"SM",0,15 OK When a SIM has no storage, the response to AT+CPMS is like the following. This response indicates there are 0 total memory areas available in SM (SIM) of which 0 are being used to store messages: AT+CPMS? +CPMS: "SM",0,0,"SM",0,0,"SM",0,0 OK So, due to the way that specific SIM SKU is configured by Verizon, the module has no ability to write messages to the SIM if there is no storage on the SIM. If that same SIM were inserted into our LVW2 products, then the same issue would exist. On the LVW3/LNA3 Verizon modules with pre-20.00.014 firmware: -No messages can be stored to SIM memory (SM) or module memory (ME) -When the SIM does have memory storage available, the message will be output to terminal if command AT+CNMI=1,2,0,2,0 is issued. -When the SIM does not have memory storage, the available message will not be output to terminal if command AT+CNMI=1,2,0,2,0 is issued. The current solution to receive SMS is to: A. Get a SIM which has indexes available B. Have the application set CNMI value such as AT+CNMI=1,2,0,2,0 to cause message to be output to terminal upon arrival. C. The application must monitor the ports of the module 100% of the time the module is powered on in order to process any SMS messages. If the module receives an SMS during a period of time when the application is not monitoring, then the messages will be lost.