Ok I open /dev/ttyUSB2
with sudo minicom -d /dev/ttyUSB2
.
However the first strange thing is that I see a few AT commands at the output of /dev/ttyUSB2
, even if I don’t type anything on the keyboard. For example:
AT+CIND?
+CIND: 0,5,1,0,1,0,1,0
OK
AT+CSQ
+CSQ: 28,0
OK
I see these “internal commands” continuously, about every 20-30 seconds. It seems there is something internal that sends these AT commands that are echoed to /dev/ttyUSB2.
I sometimes received URC +CIEV
too, but I couldn’t find any info about it on the manuals.
In this situation is difficult to send my AT commands, because what I type is intermixed with these “internal commands”.
Anyway, I tried again to send ATD<num>;
and I receive NO CARRIER.
ATD0039....;
OK
+CIEV: 1,3
+CREG: 5,"A064","3427",0
+CGREG: 5,"A064","3427",0
+CIEV: 7,3
AT+CIND?
+CIND: 0,3,1,0,1,0,1,3
OK
AT+CSQ
+CSQ: 16,0
OK
+CIEV: 3,0
+CIEV: 7,0
NO CARRIER
+CIEV: 1,5
+CREG: 5,"A44B","1363B0B",7
+CGREG: 5,"A44B","1363B0B",7
I noticed the +CREG URC after ATD. It seems the modem goes in fallback to GSM (2G). Why doesn’t it use VoLTE, staying in 4G mode?
ATI
Quectel
EG25
Revision: EG25GGBR07A08M2G
OK