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SIM

To get your modem going with a new SIM card and make things as easy as possible, follow these steps:

1. Activate the SIM Card

This might not be necessary in your country, but at least in the EU you will have to activate your SIM card with your provider. You can usually do this on the website of your chosen provider or in person when you buy the SIM card. You will need some kind of ID.

2. Test in Phone & disable PIN

Insert your SIM card in a phone, make sure it registers with the network and that you can connect to the internet. Preferably - if your phone allows it - lock it to 4G/LTE.

In the security settings, disable the PIN. Reboot your phone, make sure it does not ask for the PIN anymore and that you still register with the network and connect to the internet.

3. Test in Modem

Insert your SIM card in the modem and start the streamer.

NOTE: You will need to start the streamer with the SIM card inserted or you will have to manually reboot the modem after inserting the SIM card: AT+CFUN=1,1

Web Interface

TODO

CLI

From the CLI connect to the modem:

minicom -D /dev/ttyACM0 -b 115200

Check that the modem is available

AT

# Result
AT

Check that SIM is recognized and PIN is disabled

AT+CPIN?

# SUCCESS
+CPIN: READY

# FAIL - SIM not recognized
+CME ERROR: 10

Check tat the SIM is registered with the carrier

AT+COPS?

# SUCCESS
+COPS: 0,2,"23201",7

On success you should always see a 7 at the end, indicating that the access technology is LTE.

23201 is the carrier code. First three numbers are country code, last two carrier code - in our case 232 is Austria and 01 is A1.

Check context and IP assignment

AT+CGDCONT?

# SUCCESS IPv4 AND v6 (1)
+CGDCONT: 1,"IPV4V6","ctnet","IPV4:10.0.28.161    IPV62001:4BB8:02CC:18F7:0000:0000:E33A:AA8E",,,,0,,,,,,1,,

# SUCCESS IPv4 (2)
+CGDCONT: 1,"IP","magenta","10.145.10.20",,,,,,,,,,,,

# FAIL

In case (1) we have an IPV4V6 context. Also we are using the ctnet APN - for chinese telekom. But we are not registered to this carrier - still we get an IP address and internet is working. This means that most likely the provider ignores the wrong APN and rewrites to the default APN on the backend.

When checking the public IP address, it turns out, that it in-fact belongs to A1.

Setting APN

We want to prefer IPv4 and in cases where no APN is assigned, we can do so ourselves. A valid APN might not be necessary and the provider might ignore it, but it is a good idea to use the official one.

Automatically This will set context 1 to an IPv4 context without an APN assigned, it should then be automatically assigned by the carrier after modem reboots:

AT+CGDCONT=1,"IP",""
AT+CFUN=1,1

Check:

AT+CGDCONT?

# SUCCESS
+CGDCONT: 1,"IP","webapn.at","10.73.79.219",0,0

Manually Explicitly set the APN of your carrier:

AT+CGDCONT=1,"IP","webapn.at"
AT+CFUN=1,1

Check:

AT+CGDCONT?

# SUCCESS
+CGDCONT: 1,"IP","webapn.at","10.73.79.219",0,0

Switching SIMs

Switching between SIM cards is easily possible if you ran through the setup steps above. Just insert the new SIM card and powercycle the streamer (or reset the modem via AT commands).

AT+CFUN=1,1

Quirks

We have found that some SIM cards will not automatically register when roaming is enabled. This means that you should always disable roaming when setting or locking bands:

AT*BAND=5,0,0,482,149,1,1,0

Roaming is the third to last parameter, you can verify it the following way:

AT*BAND=5,0,0,482,149
AT+CFUN=1,1

If your SIM does no longer automatically connect, pass the parameter to disable roaming and see the SIM automagically register:

AT*BAND=5,0,0,482,149,1
AT+CFUN=1,1

Alternatively you can try forcing registration with a certain carrier:

#AT+COPS=1,2,"<MNC+MCC>"
AT+COPS=1,2,"23201"

Miscelanious and maybe helpful

Full reset and auto connect setup 

AT+CFUN=0
AT+COPS=0
AT*BAND=5,0,0,482,149,1
AT+CGDCONT=1,"IP",""
AT+CFUN=1,1

Checking things: 

AT+CPIN?
AT+CGATT?
AT+COPS?
AT+CGDCONT?
AT+CGPADDR
AT*BANDIND?

# Scan
AT+COPS=?

AT*BAND command explained

AT*BAND=<mode>,<GSMband>,<UMTSband>,<LTEbandH>,<LTEbandL>,<roamingConfig>,<srvDom>,<bandPriorityFlag>
  • mode 5 only - LTE network
  • GSMband 0 only - not relevant
  • UMTSband 0 only - not relevant
  • LTEbandH depends on region
  • LTEbandL depends on region
  • roamingConfig 0,1,2 (yes, no, no-change)
  • srvDom can only be 1
  • bandPriorityFlag 0,1,2 (default, TDD, FDD)