GL-X300BRC4 will not register T-Mobile SIM

Technical Support for Routers 4G LTE, 5G NR, USB modems
1

I purchased a GL-X750 and it worked fine but because I could not use any external 4G antenna, I purchased a GL-X300B. While my T-Mobile SIM with an active data plan works fine in the X750, it will not auto configure with the same SIM. The X300B shows that the SIM cannot be registered.

The firmware on the X300B is updated to the latest firmware and I manually entered the APN that is shown is auto configured in other routers -- fast.t-mobile.com. Still there was not change in the 'unregistered' result.

I have run out of things to try. Does anybody have any thoughts to help?

2

Doesn't the X300B also have an external antenna?
You didn't install it?

3

Yes, the X300B has an external antenna and I did install it. My comment about not having an external antenna was a reference to the X750(Spitz) that I purchased first. I then bought the X300B because it did have an external 4G antenna.

4

Try this method

AT+QGMR

Look at the module models of the X300B

5

AT+QGMR produced +CREG: 0,1

6

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There is an AT instruction page on the web page

7

the response is: EG25GGCR07A02M1G_30.200.30.200

8

Try changing your imei?
Back up your original imei before modifying it

9

The X300B now seems to connect to T-Mobile BUT there are issues. See the screenshot.
It shows good signal strength but "2G" but the SIM is 4G LTE SIM with a T-Mobile static IP address. The 192.0.0.4 is not my static IP.

10

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11

This is a CGNAT address, what LTE bands did the x750 connect to and which modem does the x750 have?

12

For the X750...
AT+QGMR returned EC25AFFAR07A08M4G_01.001.01.001

It shows the my assigned static IP access and the Cell Info shows Band 4

13

Is this the same APN you used in the X750?

Take a look AT this AT command
Try to change mtu to 1420

AT+QENG="servingcell"
14

Sorry for the delay. I have been tied up with something else earlier today.

Yes, the APN is the same for both the X750 (which works) and for the X300B (which does not work).

As info: When I enter AT_QNWINFO, I get the following returned.
+QNWINFO: "EDGE", "310260", "GSM 1900", 610.

Why is it the X300B trying to use GSM???

The Cell Info is:
0 servingcell
type servingcell
state NOCONN
mcc 310
mnc 260
lac A263
cellid 53E
rxlex -80
rat GSM (note: this line is in red while the others are black)
1 neighbourcell
2 neighbourcell
3 neighbourcell

15

To disable GSM

AT+QCFG="nwscanmode",3

To band scan

AT+QOPS

Quectel AT commands are available as a 317 page manual if needed.

Can you see Band 4 with the EG25?

16

Both the "AT+QCFG" and the "AT+QOPS" suggested 'failed to execute'.

When I set device to /dev/ttyUSB3, it will not work at all.
When I set it to /dev/cdc-wdm0, it connects but with GSM

I am still total confused as why the auto configure will not work on the X300B like it does on other products...

17

I'm wondering if you have a loose cable.
Can you open the x300 and share a photo of the modem connections

18

I have 2 of these X300B devices and they both exhibit the exact same results. I purchased these and received them a week ago. These are pictures of one of the two devices.

IMG_5976
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IMG_5975
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19

Without DV wired in you are not going to see any LTE signals, Band 4 requires Receive Diversity.

20

WOW! So the only X300B that supports LTE is the -GPS version? With all the information on the website, I would have thought this would have been made clear somewhere. The implication is that all of the Collie models support LTE.
I guess the two that I bought will get returned this week for credit!