I have an AT&T M2M SIM card which I have used in multiple other modems successfully, but when I try to put it in my MC7455 and connect to the LTE network, I am unsuccessful.
I can see the SIM as online in the AT&T SIM dashboard they provide, and the ppp0 interface obtains an IP address successfully via wvdial, but it doesn’t seem like I am actually registered / connected to the network.
The APN is set correctly and here is the result of a few diagnostic AT commands sent to the modem:
ATIE
Manufacturer: Sierra Wireless, Incorporated
Model: MC7455
Revision: SWI9X30C_02.24.05.06 r7040 CARMD-EV-FRMWR2 2017/05/19 06:23:09
MEID: 35907206237905
IMEI: 359072062379058
IMEI SV: 12
FSN: LQ823242490210
+GCAP: +CGSM
OK
AT+CSQ
+CSQ: 17,99
OK
AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","m2m.com.attz","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0
OK
AT+CGREG?
+CGREG: 0,1
OK
The AT!USBCOMP is set with the bitmask 50D, not sure if that makes a difference, I tried 100D as well and it had the same behavior.
Let me know if you need any more information, or want me to run any additional AT commands.
I’ve exhausted my troubleshooting methods and have scoured the web already, but no solutions I’ve found have been a help.
First, you need to check if the module attaches to the network: AT!GSTATUS? and AT+COPS? will tell. After the module attaches to the network, then next is to establish data session.
USBCOMP 50d presents 2 network interfaces and 3 USB serial ports (AT, NEMA and debug (DM))
AT!GSTATUS? and AT+COPS? result show the module attaches to the WCDMA/UMTS network. AT+CGREG? shows the module is registered to home network. You also mentioned the ppp0 interface obtained IP address, every thing looks OK. So what’s the concern?
By the way, I switched from using the AT&T SIM card I was initially trying to the Sierra Wireless smart SIM card we have to see if it makes any difference.
As far as I can tell, I am getting the exact same behavior though.
This is what wvdial shows (I ran this last night):
root@igt20:~# wvdial
--> WvDial: Internet dialer version 1.61
--> Cannot get information for serial port.
--> Initializing modem.
--> Sending: ATZ
ATZ
OK
--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
OK
--> Sending: AT+CGDCONT=1,"IPV4V6","internet.sierrawireless.com"
AT+CGDCONT=1,"IPV4V6","internet.sierrawireless.com"
OK
--> Modem initialized.
--> Sending: ATDT*99***1#
--> Waiting for carrier.
ATDT*99***1#
CONNECT 150000000
--> Carrier detected. Starting PPP immediately.
--> Starting pppd at Tue Aug 21 18:58:00 2018
--> Pid of pppd: 1877
--> Using interface ppp0
--> pppd: `X▒
--> pppd: `X▒
--> pppd: `X▒
--> pppd: `X▒
--> pppd: `X▒
--> pppd: `X▒
--> local IP address 100.71.188.140
--> pppd: `X▒
--> remote IP address 10.64.64.64
--> pppd: `X▒
--> primary DNS address 8.8.8.8
--> pppd: `X▒
--> secondary DNS address 4.2.2.2
--> pppd: `X▒
I did find this forum post in which someone else mentioned that the MC7455 may not work for some carriers with the generic firmware (which I have): no cellular service for em7455 with window10!
Using PPP with the MC’s is perfectly valid but not generally the way people do it as the interface is a little slow of you want max performance, also integrators want to use Ethernet interfaces. Are you using the Sierra Wireless drivers or the open source ones?
You might want to try using the RMNet interface rather than PPP as per the attached document, it say MC73 but is actually applicable to MC74 (and EM75) as well.