AT command for R11e-LTE7 to disable incoming voice calls

vniic · May 18, 2026, 7:25am

(for certain reasons, I can't get an answer through the support portal, so I'm creating a thread here)

I am currently migrating from a hAP ax lite LTE6 (FG621-EA modem) to an SXT LTE7 kit, which is equipped with the R11e-LTE7 modem (in the logs and in the photo on the website it is called "r11l-LTE7", but in the description on the site for some reason it's "r11e-LTE7").

On the previous device (FG621-EA), I was able to disable the modem’s reaction to CSFB (Circuit Switched Fallback - i.e., the automatic fallback from LTE to 3G upon an incoming voice call) by using the following AT command:
/interface lte at-chat lte1 input="AT+GTSET=\"CALLBREAK\",1"

When this command was applied, the modem completely blocked incoming voice calls and remained registered in LTE mode even when a call was received. The caller would hear that the subscriber was unavailable, and the call was rejected directly by the modem.

This command was specific to the previous modem manufacturer (Fibocom).

For the new R11e-LTE7 modem, I have not been able to determine the manufacturer, and the above command does not function on this device.

I’d like some advice on two questions:

Is there an equivalent AT command for the R11e-LTE7 modem that allows complete disabling of incoming voice calls and/or prevents CSFB behaviour ?
If such functionality is not supported via AT commands on this model, is it possible to enable VoLTE on the R11e-LTE7 modem ? While the modem itself would not handle traditional circuit-switched voice calls, enabling VoLTE (if supported) would allow the device to remain in LTE mode during incoming calls and avoid fallback to 3G.

I can't completely disable incoming voice calls through my mobile operator and/or block the modem in LTE mode – I need SMS messages, and blocking LTE or disabling voice through the operator also blocks incoming SMS.

optio · May 19, 2026, 5:34pm

If this is Quactel manufacured modem I think there is no specific AT command to disable CSFB only for voice call, but you can lock modem scan for LTE network only with AT command AT+QCFG="nwscanmode",3; or better use ROS config on lte interface and unset all network modes except LTE.

vniic · May 20, 2026, 8:36am

I tried to 'lock' it to LTE, and it blocks incoming voice calls, but in LTE mode (if we disable 3G in the LTE interface properties via ROS), USSD requests don’t work: if we disable 3G support and leave only LTE (through Winbox, for the lte1 interface) - commands like /interface lte at-chat lte1 input="AT+CUSD=1,"*121#",15" stop working (the command executes, but the result is empty).

If USSD is not needed, then the method with the LTE mode "lock" works, thanks.

Who the modem manufacturer is - unclear, neither on the Mikrotik website nor on the separate modules sold (r11l-lte7) is the manufacturer listed. Possibly some OEM made specifically for Mikrotik.

optio · May 20, 2026, 3:51pm

Does AT command ATI works on your modem and if does which is response?

In my case on Chateau 5G R17 ax is:

> /interface/lte/at-chat lte1 input="ATI"
  output: Quectel
          RG650E-EU
          Revision: RG650EEU00AAR01A04G8G
          OK

In product brochure for Chateau 5G R17 ax modem manufacturer Quectel is not mentioned, but this AT command outputs it.

vniic · May 21, 2026, 6:28am

For your Chateau 5G R17, the description from Mikrotik says "RG650E-EU" (the full model name is S53UG+5HaxD2HaxD-TC&RG650E-EU, for versions with a modem, the modem name is given after the '&'), which immediately comes up in a search at https://www.quectel.com/product/5g-rg650e-series/

For my model, a search finds nothing, but the response to "ATI" looks like a "custom OEM":

> /interface/lte/at-chat lte1 input="ATI"
output: MikroTik
OK

Also:
> /interface/lte/at-chat lte1 input="AT+CGMI"
output: +CGMI: MikroTik
OK

> /interface/lte/at-chat lte1 input="AT+CGMM"
output: +CGMM: R11l-LTE7
OK

> /interface/lte/at-chat lte1 input="AT+CGMR"
output: R11l-LTE7_V005
OK

if we create a supout.rif file and search for "LTE7" in all sections, then in the hardware(0F) section we see:

1 location="1-1" parent=1-0 type=usb vendor="MikroTik" name="R11l-LTE7" serial-number="123456789ABCD" vendor-id="0x2cd2" device-id="0x0006" speed="480" usb-version=" 2.10"
irq=0 owner="system" device-path=""

vniic · May 21, 2026, 6:34am

More about the modem, about this new r11l-LTE7 (though maybe it's the same with other models — I don't have any other models to compare right now) — sometimes SMS PDU show up in ROS with some kind of 'junk', for example:

> /tool/sms/inbox/print detail
0 source="lte1" phone="MiXX" type=class-0 timestamp="2026-05-20 09:33:40+03:00" message="? ???? ???????? MiXX ????????? ?????? ?? ?????? ? "???????". ?????"
pdu="07919740430901F44407D0CD34160B0008625002903304218A0500038803010412002004320430044804430020043F043E0434043F04380441043A04430020004D00690058005800200434043E043104300432043B0435043D043000200441043A0
4380434043A04300020043D0430002004370430043A04300437044B00200432002000220424043B043004430432043004430022002E00200412043E0441043F043E\r\n"

but directly from the modem – everything is fine:
> put ([/interface lte at-chat lte1 input="AT+CMGL=4" wait=yes as-value]->"output")
+CMGL: 1,1,,155
07919740430901F44407D0CD34160B0008625002903304218A0500038803010412002004320430044804430020043F043E0434043F04380441043A04430020004D00690058005800200434043E043104300432043B0435043D043000200441043A0438043404
3A04300020043D0430002004370430043A04300437044B00200432002000220424043B043004430432043004430022002E00200412043E0441043F043E

This "\r\n" sometimes (!) gets added to the PDU hex (!) property, but not always; sometimes it’s there, sometimes it’s not.
(redirecting to a file by adding "file=filename" doesn't help either — the file still has these "garbage" "\r\n" as such "control words" meaning CRLF, i.e., it's not a problem with output to the terminal window)

Tried switching "/tool/sms/set sms-storage=" from "sim" to "modem" – it doesn’t help.

For now, when parsing SMS, I manually look for these "\r\n" in the hex string and remove them, it’s clearly some kind of "junk".

Regarding the original issue (blocking incoming voice calls) - for now I left it in LTE mode (unchecked the 3G option). USSD commands don't work, but at least the modem doesn't 'fall back' to 3G for incoming voice calls.

optio · May 21, 2026, 2:42pm

It seems modem is branded for MT, but original manufacturer can be still Quectel, this can be checked if some Quectel specific AT command works (with AT+Q prefix), like AT+QCFG=? this should output current modem config settings if is Quectel.

vniic · May 22, 2026, 6:35am

Thanks for the information about the AT+Q.. command set.

I won’t have access to this modem for the next two weeks, but I’ll definitely check afterwards if it supports commands from Quectel.

vniic · June 1, 2026, 6:39am

I tried commands with the AT+Q prefix – I got an "error" on all of them:

> /interface/lte/at-chat lte1 input="AT+QCFG=?"
output: ERROR

On a third-party forum, in a post from 2018, I found some info about the r11e-lte (an older one, but also "from Mikrotik" and without specifying the actual manufacturer): "In fact, it’s a MIFI modem on a PXA1802 chip" and a link to a set of commands for the "luat lte module." I tried some – they work, for example:

> /interface/lte/at-chat lte1 input="AT^HVER" 
output: ^HVER:"Rev 0000"
OK

> /interface lte at-chat lte1 input="AT*MRD_SN=R" 
output: *MRD_SN:0201,Thu Jan 1 07:59:59 1970,HK803JX1QYF
OK

> /interface lte at-chat lte1 input="AT+CLCK=?"        
  output: +CLCK: ("CS", "PS", "PF", "SC", "AO", "OI", "OX", "AI", "IR", "NT", "NM", "NS", "NA", "AB", "AG", "AC", "FD", "PN", "PU", "PP", "PC" )
          OK

 > /interface lte at-chat lte1 input="AT+CLCK=\"AI\",2"  
  output: 
...
          ^MODE:17,17                          
...
          +CLCK: 0                             
          OK

Then I tried the AT+CLCK="AI",1 command:

> /interface lte at-chat lte1 input="AT+CLCK=\"AI\",1" 
output: +CME ERROR: operation not supported

didn’t work. I tried different passwords, but it gives the same response every time.

Result: I stopped looking for other options and turned off 3G, leaving only LTE — even if USSD doesn’t work, at least incoming voice calls get blocked.

optio · June 1, 2026, 3:55pm

I see, so it's modem from different manufacturer... FYI here is AT commands manual for PXA1802 modem https://manuals.plus/m/7c9f38f0fece78fc7672b6cc148ecd6f118d4dd45b0e151eaa7dbf7b93a4ccb1 if it helps...

vniic · June 2, 2026, 6:22am

Is it really the case that nobody else bothers with blocking incoming voice calls to avoid CSFB ?

If it's a common 'problem,' the RouterOS developers could add a 'switch' in the interface to toggle the necessary key for a specific modem, if the modem is built-in and from the list chosen by Mikrotik engineers/programmers.

(About a month ago, I checked this question with tech support on the portal, but regarding the Fibocom modem, they gave me a command for a specific modem, not a general solution)

vniic · June 2, 2026, 11:52am

Yes, you have the same documentation as I do (mine is above, the link with the word 'luat lte module', 167 pages 'Luat LTE Module. AT Command Interface. User Manual. Rev1.0')

optio · June 2, 2026, 6:54pm

Ah, didn't notice that URL in your post...

Regarding why is this not common issue, could be that most users which use LTE router have only data plan, I have for example, call to my number is blocked by MO and I don't need to disable 3G because of CSFB issue because call is not even reaching modem.

Try with MT support, open ticket there with issue description and maybe they will provide AT command(s) which can mitigate this.

vniic · June 2, 2026, 7:08pm

The problem is that, for some reasons, at the moment (something changed in their policy in the last month, because back at the end of April 2026 - requests were accepted and responded to) tech support does not accept my requests: requests are accepted, they ask for the Supout.rif file, and when I send it - they find something in it and reply that "We are unable to continue providing the requested service due to mandatory and binding regulations of the European Union, United Nations, and/or USA (e.g. Office of Foreign Assets Control (OFAC)) on export control and economic sanctions against your region."

Therefore, I posted the question here on the forum.

optio · June 2, 2026, 7:14pm

It seems you are from country that is under sanctions. I didn't know that even MT support needs to follow such regulations, bad luck I guess.

Maybe will someone respond who had similar issue...