I’m running into an issue with a Quectel RG255C-GL.
I can attach to the network, define a PDP context, and dial a data call successfully (e.g. ATDT99**1# over Telnet to the module). The PPP session comes up fine.
If I then drop back to command mode (+++) and hang up with ATH0, the call ends as expected. I also tried deactivating the context with AT+CGACT=0,1 and/or detaching/reattaching with AT+CGATT=0 / AT+CGATT=1.
The problem: after this, any attempt to redial with ATDT99**1# just returns NO CARRIER.
The only way to get it working again is to reset the module.
root@debian-sd:/home/display/btros/ppp# telnet <some_IP> 23
Trying <some_IP>...
Connected to <some_IP>.
Escape character is '^]'.
AT
OK
AT+CGACT?
AT+CGACT?
+CGACT: 1,1
+CGACT: 2,1
+CGACT: 3,0
OK
AT+CGPADDR
AT+CGPADDR
+CGPADDR: 1,"<some ip>"
+CGPADDR: 2,"<some ip>"
+CGPADDR: 3,
OK
AT+CGATT?
AT+CGATT?
+CGATT: 1
OK
ATDT*99***1#
ATDT*99***1#
CONNECT 150000000
^]
telnet> quit
Connection closed.
root@debian-sd:/home/display/btros/ppp# (sleep 1; echo -n "+++"; sleep 1) | socat - TCP:<some_IP>:23
root@debian-sd:/home/display/btros/ppp# telnet <some_IP> 23
Trying <some_IP>...
Connected to <some_IP>.
Escape character is '^]'.
AT+CGACT?
+CGACT: 1,1
+CGACT: 2,1
+CGACT: 3,0
OK
AT+CGATT=0
AT+CGATT=0
OK
AT+CGACT?
AT+CGACT?
+CGACT: 1,0
+CGACT: 2,0
+CGACT: 3,0
OK
AT+CGATT=1
AT+CGATT=1
OK
AT+CGACT?
AT+CGACT?
+CGACT: 1,1
+CGACT: 2,1
+CGACT: 3,0
OK
AT+CGPADDR
AT+CGPADDR
+CGPADDR: 1,"<some_IP>"
+CGPADDR: 2,"<some_IP>"
+CGPADDR: 3,
OK
ATDT*99***1#
ATDT*99***1#
NO CARRIER