Error sending SMS after firmware update

NETWORKING SOLUTIONS
1

I’m using a TRB142 modem and in the past I developed an application to send SMS using the RS232 port and the AT commands. I deeply tested the application with the firmware version TRB1_R_00.07.05.4. Last day I tried with version TRB1_R_00.07.08.2 and my application didn’t work. Then I tried with the last available version TRB1_R_00.07.13.4 and got the same problem. Below the details of my test.

Message: test
Mobile number: 0039347*******
Message format: PDU

The log printed by my application:

Initializing modem AT+QCSQ=0
Answer: 
OK

Send AT+CMGF=0
Answer: 
OK


Send AT+CMEE=2 answer: 
OK

Send: AT+CMGS=19

Send:
<sequence of 40 2-digits hex values>1A0D0A 

Answer: 
+CMS ERROR: invalid PDU mode parameter

Note that the PDU string is terminated with a CTRL-Z char (1A) and a \r\n. I already tried all possible combination of this 3 characters, without success. I know having the PDU string may help, but that contains my real mobile number that I don’t want to share here.
Hope somebody can help. Thank you.

3

Hello,

Could you please confirm whether this issue with sending SMS in PDU mode is still present on the latest 7.14.1 firmware release?

From the initial view, it seems that the length parameter in AT+CMGS=19 doesn’t match with the PDU string length (40 hex values) – it should be a higher number. I recommend using this SMSTools3 PDU Converter PDU converter for your message, where you only have to input the receiver’s number, text and convert it.

Additionally, as a troubleshooting step, have you tried sending an SMS using text mode instead of PDU, just to verify if the basic SMS functionality works as expected?

Best regards,