
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: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Telephone is an open source SIP softphone and VoIP client for making audio and video calls over the internet. It supports standard telephony features like call waiting, call forwarding and voicemail.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API