Description: CSipSimple is an open source SIP client for Android that allows you to make VoIP calls over Wi-Fi or mobile data. It supports common SIP features like call transfer, call forwarding, call waiting, 3-way conferencing, etc.
Type: software
Pricing: Open Source
Description: Ubuntu is a free and open source Linux distribution based on Debian. It is easy to use, highly customizable, and has a large community supporting it.
Type: software
Pricing: Free