AT commands are very helpful for troubleshooting your device and changing the settings that are not available from standard Windows settings. For example, you can choose the access technology – 2G, 3G, 4G and even stick to particular frequency bands.

EM7345 is using Intel (formerly Infineon) AT command set and it’s not compatible with Quallcomm AT command set. All basic AT commands like AT+CFUN are more or less the same for all 3G/4G devices, but advanced ones, starting from AT+X, are unique to Intel XMM platform devices.

No official documentation for AT commands was released by Intel, all I was able to find is some source code fragments for Samsung phones (that are based on the earlier XMM platform, like XMM 6380, or so) on GitHub.

To use AT commands, first you have to enable EM7345 AT command port, as I described in this post.

There are many cases when your newly installed EM7345 doesn’t work. Let’s start step by step.

AT+CFUN?

should return: +CFUN: 1,0

1 means the device is turned on. If it’s not 1, make sure your EM7345 is turned on in Windows Connection Manager. Or try to turn it on using the AT command:

AT+CFUN=1

Let’s check if the SIM card is working and recognized by the EM7345:

AT+CIMI

should read from your card and display your IMSI number.

Check your SIM card status:

AT+CPIN?

should return: +CPIN: READY. That means your SIM card is properly recognized and no SIM card PIN is required to enter.

Let’s check if your EM7345 is SIM locked:

AT+CLCK=”PN”,2

should return +CLCK: 0

0 means your device is not locked and can work with any SIM card. If it is 1, then bad luck, your EM7345 is SIM locked and will work only with SIM card of the operator it is locked to.

Let’s check which access technology is currently used:

AT+XREG?

returns something like +XREG: 0,8,BAND_LTE_20,0

it means your device is currently using LTE, frequency band 20. For 3G, the band will be BAND_UMTS_I, for example. That means 3G band I. All actual band frequencies you can find in Google.

How to change the access technology?

AT+XACT=n

where n is: 0 – for 2G (EDGE), 1 – for 3G, 2 – for 4G/LTE.

You can also check your current access technology configuration:

AT+XACT?

response: +XACT: 0,0,,900,1800,1900,850,1,2,4,5,8,101,102,103,104,105,107,108,113,117,118,119,120

the first number is n number above. Then come numbers 900,1800,1900,850. Those are bands currently enabled for 2G technology. So the configuration is to use only 2G, and use the above bands. If the band is not listed, it won’t be used by the EM7345. This is very useful when you want to stick to only one access technology and even some particular band. Then we see numbers 1,2,4,5,8. Those are 3G bands. And finally, numbers starting from 101 and up to 120. Those are 4G/LTE bands. 101 means LTE band 1, 102 stands for LTE band 2 and so on.

How do we set the bands? For example to use only LTE band 20, use the following command:

AT+XACT=2,,,120

To stick to LTE bands 7 and 20, use:

AT+XACT=2,,,107,120

You get the idea.

What about automatic selection of access technologies? For example in some areas where 4G is not avaialble and you want the device to use 3G and then go back to 4G when you’re back to the coverage? Use this:

AT+XACT=6,2,1,900,1800,1900,850,1,2,4,5,8,101,102,103,104,105,107,108,113,117,118,119,120

That tells your device to use all access technologies and the bands listed in the command (6 number) with the priority of 4G/LTE. This is the default factory EM7345 setting. What 2 and 1 numbers mean I don’t know yet.

If your SIM card seems to be ok, but you cannot get a working connection, try to check for connection errors:

AT+XEER

AT+CEER

AT+NEER

Each of it will get you some text error report if your EM7345 cannot connect to a network.

Your device is frozen or you get “1 CDC error”? No need to reboot your laptop, just use:

AT+CFUN=16

This will reboot your EM7345, and it will reappear in Device Manager shortly.

Want to check your EM7345 for internal errors? Use:

AT+XLOG=0

This will list all recorded errors (exceptions). Firmware version 1.1 had some bugs, and every time “1 CDC” error appeared, it got logged and appeared in this list. Since version 1.2 (1415.09) I see no errors in this log.

To clear this list of errors, use:

AT+XLOG=2