Description: Asterisk is an open source communications software that allows you to build telephony applications and services. It supports voice over IP, video conferencing, voicemail, auto attendant, interactive voice response, and more. It can be used to build PBX systems, call center solutions, and other communications platforms.
Type: software
Pricing: Open Source
Description: Telegram is a cloud-based instant messaging and voice over IP service. It offers end-to-end encrypted video calling, file sharing, and several other features. Telegram clients exist for both mobile and desktop systems.
Type: software
Pricing: Free