VoIP / SIP Settings on different versions of Android

Android phones come with a native VoIP client that works great. The settings are placed in different paths though, in this post I'll list the path to the setting on different versions of Android:

Android 4.2.2 (Jelly Bean) - (Huawei Y330):
Dialer App -> Settings -> Internet Call

Android 5.0 (Lollipop) -  Asus Fonepad 7 FE171CG:
Settings -> Call Settings -> Phone account settings

Android 5.1.1 ((Lollipop)  - Huawei Redmi 3:
Phone App -> Settings -> Advanced Settings -> SIP Settings

Android 9 (Pie) - Mi A3 / A1:
Phone App -> Settings -> Calling Accounts

How to configure VoIP on GreenPacket DT-350

آموزش راه اندازی تلفن اینترنتی VoIP بر روی مودم TD-LTE DT-350 ایرانسل

Irancell TD-LTE TD-350 modem offers a hardware VoIP client and one can connect a phone to the RJ45 port on the modem to use this feature. However, VoIP settings are disabled by default and it is not possible to enable it using the admin user since this user is an Enduser and not a Superuser.

 

Thanks to this post, it is possible to find the superuser defined for Greenpacket modems. Irancell has set the username for superuser on its modems to administrator and the password is also administrator: 

User: administrator

Pass: administrator

This user has privileges to manage many more settings including VoIP settings :

And Voila! It works pretty well!