Unable to switch to LTE on MC7700

IoT Modules MC/EM Series
1

I’ve noticed that in areas of LTE coverage, my modem is not using LTE, and only using HSPA+.

My carrier is AT&T (US).

I just updated the firmware to SWI9200X_03.05.29.03ap (AT&T DIP), but I got the same result with the current and previous versions.

Result of AT!SELRAT=?
!SELRAT: Index, Name
00, Automatic
01, UMTS 3G Only
02, GSM 2G Only
03, Automatic
04, Automatic
05, GSM and UMTS Only
06, LTE Only
07, GSM, UMTS, LTE
11, UMTS and LTE Only
12, GSM and LTE Only

Result of AT!SELRAT=6
ERROR

Result of AT!SELRAT=7
ERROR

Result of AT!SELRAT=1
OK

Result of AT!SELRAT=2
OK

Result of AT!BAND=?
Index, Name
00, All bands
01, Europe 3G
02, North America 3G
03, Europe 2G
04, North America 2G
05, GSM ALL
08, WCDMA ALL

2

Finally figured it out!!!

For those who encounter the same issue:

I ran AT!ENTERCND=“A710” for password-protected commands.
Then AT!NVBACKUP=0 to backup the factory calibration.
AT!NVDEF to restore default configuration.
Finally, AT!NVRESTORE=0 to restore factory calibration, and AT!RESET to restart modem.

NOTE!!! All settings will be erased, and have to be reprogrammed!

But, I can finally enable LTE using AT!SELRAT.

3

Hello,

I used your procedure except the AT!NVRESTORE so I made the RESET by mistake. Now the MC7700 is not detected anymore.

Is there any emergency procedure to fix this issue?

Regards