MC5728V: SMS over CnS

I am attempting to send SMS messages through CNS commands on a MC5728V. The code I’ve written can receive and process incoming messages, but when I try to send a message, the message will be sent to it’s destination completely blank. The modem doesn’t report any errors when I write the message, and reports that there was no error when it is sent.

Here is the log of the communication between the host and the modem:

#send SMS header 
Sending  : 7E 00 C6 2B 00 20 03 03 00 F0 05 BA 11 00 BC 10
           11 00 01 00 B6 00 00 06 40 00 01 00 00 00 02 00
           00 00 00 0A   --NUMBER TO SEND SMS TO--   00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
           00 00 00 00 00 02 13 06 28 15 27 55 00 00 00 00
           00 00 00 00 00 00 00 00 00 00 01 7E
#modem acknowledges          
Receiving: 7E 00 0A 6B 00 20 03 04 00 F0 05 BA 11 00 00 7E
#Send (only) data packet 
Sending  : 7E 00 1C 2B 00 20 03 03 00 F0 05 BA 11 00 12 10
           11 01 03 00 0C 48 65 6C 6C 6F 20 57 6F 72 6C 64
           21 7E
#modem acknowledges           
Receiving: 7E 00 0A 6B 00 20 03 04 00 F0 05 BA 11 00 00 7E
#Register to receive the sent message notification
Sending  : 7E 00 0A 2B 00 20 05 05 00 F0 05 BA 11 00 00 7E
#modem acknowledges
Receiving: 7E 00 0A 6B 00 20 05 06 00 F0 05 BA 11 00 00 7E
#Send outbox to network
Sending  : 7E 00 0A 2B 00 20 04 03 00 F0 05 BA 11 00 00 7E
#modem acknowledges
Receiving: 7E 00 0A 6B 00 20 04 04 00 F0 05 BA 11 00 00 7E
#notification 
Receiving: 7E 00 10 6B 00 20 05 07 00 00 00 00 00 00 06 10
           11 00 00 00 00 7E

As far as I can tell, based on the CnS reference document, this should result in an SMS containing “Hello World!” should be sent to the phone number in the header. An SMS is sent to that phone number, but it contains no text, it is completely blank. To make sure the modem was working properly, I sent an SMS via AT command, and it arrived in good order, so I’m pretty sure this isn’t a hardware or configuration problem. Has anyone else had similar problems? If so what were your solutions?

Hi,

Could you please try sending sms using watcher :question:

While sending sms, monitor the CnS port using any port monitoring tool to capture CnS logs.

Thanks

Sorry I didn’t specify, I’m trying to do this on linux. So using watcher isn’t an option for me. Using the Linux SDK example code I was able to send an SMS successfully, but every serial sniffer I’ve tried has intercepted the packets rather than passed them through.

Hi
I want to access the CnS port and am looking for code samples. Where (exactly) can I download this Linux SDK ?
Thanks

I figured out my problem, I was setting the parameter bit-mask of the SMS header incorrectly, and it resulted in the User-data flag not getting set. fixing that problem resolved the issue.