Using the nRF9160 against Anritsu MT8821C In Signaling Callbox Mode

Using the nRF9160 against Anritsu MT8821C In Signaling Callbox Mode

This is a guide showing how to use the Anritsu MT8821C tester against Nordic's nRF9160.

Please use at least Cat-M version 40.10#205, NB IoT version 40.00#013 and Platform SW v40.10S#205 or later versions to have all required MT8821C implementations available when testing against the nRF9160

Setting up

The RF attenuations between the nRF9160 and MT8821C can be modified from "External Loss"

Use Nordic proprietary AT commands for selecting LTE-M1 or NB-IoT mode.



Before triggering an attach with AT+CFUN=1, you need to send AT+CFUN=4 for the detach procedure first.

The full list of AT commands supported by Nordic can be found here:

Cat-M Common settings

Cat-M Call Processing settings

NB-IoT Call Processing settings

Use SIM model number P0035 when the default Anritsu SIM card is used in "Authentication / Integrity"
Use integrity protection other than "Null" as the "Null" algorithm might not be supported in all nRF9160 builds (also in "Authentication / Integrity" selection)

Always enable "Half Duplex" functionality where selectable in Cat-M1 testing (full duplex will not work properly against nRF9160)

To enable UE to go to RRC idle mode after registration, use "RRC Release During Registration" from "RMC". This needs to be selected before starting the attach procedure.
To enable UE to go to RRC idle mode after other connections, select "use RRC state transition" from selection "General->Packet"

The selection "Inactivity Timer" in "Call Processing->Packet" keeps NB-IoT RRC connection alive until timer expires (in case there is no any data exchange ongoing).
For signaling RF testing, RRC connected mode is required (for RF related testing, it is recommended to use RMC mode from "Common->Signal->Channel Coding->RMC")

For the RSRP and RSRQ measurements being reported by nRF9160 on the own cell, select "Common->General-Scenario type 6" and EventA1 from "General->Measurement report" and enable measurement reporting from the GUI.
You can also use periodic measurements by selecting "General->Measurement->Periodical"

For the IP data application (Using Iperf and Ping from MT8821C (internally, without Control PC) can be found from "IP data"):
Cat-M1 : Set following parameters as below :
"Common->General->Scenario->Type 6"
"Common->Signal->Channel Coding->Packet"
"Call Processing->RMC->Test Mode->Off"

NB IoT :
"Common->Signal->Channel Coding->Packet"
"Call Processing->RMC->Test Mode->Off"
"Common->UL RMC->MCSIndex->"at least 4""

Options for Cat-M1 & NB IoT IP data testing :
- Cat-M1 & NB IoT IP Data Transfer SW options needed.

Taking logs

Select "menu" from UI : "Log->Save signaling log", saved *.lge log might be enough for debugging.
The *.lge file can be viewed with PA3 viewer and will help in debugging (along with the nRF9160 modem trace).

Recallable Anritsu MT8821C configuration files
- files are available on request for both M1 and NB IoT. For recalling use "Menu->Parameter Save/Recall->Recall" and select file to be recalled.

  • Hello,

    Thank you for the question.

    We haven't connected to the internet as MT8821C has Windows OS and doesn't have all the latest security updates.
    From nRF9160 point of view only APN configuration should be enough, see chapter 7.18 in AT command specification:

    Was this set in your testing: "Common->Signal->Channel Coding->Packet" ?

    Best regards,


  • Hello,

    I face another scenario where my 9160 connected to the 8821C, and I can ping the computers in the same local network ( But I can not ping to the internet ( Is there a gateway setting in 9160? Or something I need to configure in order to access the internet?

  • Hello, 

    Very nice to hear that nRF9160 is now working correctly against Anritsu MT8821C in your test lab.

    I will check why might not work as it should.

    Merry Christmas!

    Best regards,


  • Hello,

    I just came to let you know that now everything seems to be working between Anritsu and nRF9160.  

    Anritsu's customer support provided the latest Cat-M1 FW (40.105#206 ) to the test lab very quickly, but we didn't get to try it right away.

    However, that Anritsu's configuration file ( you shared earlier didn't work even with the latest FW. Anrtisu announced again "illegal file" when they tried to recall the file to the Anritsu. However, this doesn't matter anymore.

    And I have to admit that the instructions in this article are up to date and correct. We should have just immediately trusted the note at the beginning of the article and requests the latest FW version from Anritsu.. Thanks for your patience and Merry Christmas!

    Best regards


  • Hi,

    And thanks again for the quick reply. The test laboratory has now contacted Anritsu and asked about the firmware in question. I'll let you know when we get to try it.

    Best regards