I was able to get it to work! install minicom:
opkg update
opkg install minicom
Check the baud rate:
stty -F /dev/ttyUSB2
speed 9600 baud; line = 0;
min = 1; time = 5;
ignbrk -brkint -icrnl -imaxbel
-opost -onlcr
-isig -icanon -iexten -echo -echoe -echok -echoctl -echoke
Connect to the modem:
minicom -b 9600 -D /dev/ttyUSB2
Enable Local Echo to see entered commands:
CTRL+A then E
AT+CMGF=1 then hit Enter
AT+CMGS=“+phonenumber” then hit Enter
> write your message which does not appear on minicom then hit CTRL+Z+CMGS: 8
OK
To exit
CTRL+A then Q then Enter
NOTE: the first and second AT commands needs to be entered as fast as possible! Otherwise you will receive the +CMS ERROR: 304
Screenshot PoC:
First time it failed because of the delay in pasting the second command!