VoLTE support


VoLTE feature is supported by default on Amari callboxes but it frequently happens that the feature is locked at UE side , for many different reasons.

This wiki page aims to list tricks that can help you to unlock the feature at UE side and test VoLTE feature using our callbox .

NOTE : For a tutorial about testing VoLTE, click here.


VoLTE option in phone menu

VoLTE is an option and can be disabled by default in phone menu .

  1. Check that VoLTE option is enabled in phone setting menu > network∼ menu

There is also a hidden menu on some Devices where VoLTE can be enabled .

  1. Dial *#*#4636#*#* on your phone
  2. Go in phone information menu and toggle the VoLTE option if disabled

Note : If you face difficulties to find phone that supports VolTE, please contact We can provide you with models that support the VoLTE even with test sim cards.


Test SIM card

When using test sim cards, it may happen that UE locks the VoLTE feature if "UE operation mode" byte is not set to "type approval operations" in USIM Elementary File Administrative Data(EFad).

Solution :

  1. Set "UE operation mode" byte as "type approval operations" in USIM's Elementary File Administrative Data(EFad) field.
  2. Or use Amarisoft Test sim card



Some devices have a white list of authorized PLMN where VoLTE can be enabled. If you run your test with a test sim card ( with mcc/mnc 00101 as instance), VoLTE may be turn off automatically

Solution :


SMS is OK but not VoLTE

It frequently happens that when testing IMS functionality , SMS looks OK but VoLTE is not .

This may simply signify that IMS service is not active and SMS has been sent over SG (as our IMS server is acting as SMSC as well) and that VoLTE fails because circuit switch fallback (CSFB) is not supported in 4G .

In both case , IMS service is not involved and means that VoLTE is disabled at UE side


Android Carrier Privileges

Other interesting info regarding VoLTE lock and solution:



In order to troubleshoot VoLTE, you can trace the IMS server and MME using our webgui (port 9003 and 9000 respectively)

You should see REGISTER and INVITE messages if UE supports VoLTE

UE must trigger a PDN with the well known "IMS" APN and get in return the p-CSCF IP address .Note: By experience , most of the UE have this APN name (IMS) hardcoded. Setting manually a APN "IMS" doesn't unlock the VoLTE functionality