Differences between "typed" and "sent" commands.

Hi, I’ve noted strange behaviour, using modules like WMOD2, WMoi3 and Integra.

Let’s imagine I have the following AT command:


If I type the command through keyboard (connected through serial COM) I have the correct answer (I can see SMS stored).
If I send out the same string through a PIC I have no answer.
I’ve been thinking there was a trouble in the code, but if I change the command (AT or AT+CSQ) I have the correct answer.

I also placed a serial log across the serial line, modem sends me echo of sent characters correctly.
The serial speed (keyboard and microcontroller) is correct.
I also placed a 200ms delay between every char.
What can be wrong?

https://forum.sierrawireless.com/t/fastrack-go-command-duplexing/4258/9 :question: