3CX

3CX is a software-based business phone system founded in 2005 and headquartered in Nicosia, Cyprus. It offers a SIP-standard PBX that runs self-hosted on Windows or Linux, in containers, or in 3CX-hosted cloud, with bring-your-own SIP trunking, web client, desktop and iOS/Android softphones, plus admin and management consoles. Calling features include extensions, queues, conferencing, video meetings, live chat and CRM integrations. Pricing is licensed by simultaneous calls rather than per user: a free Standard tier covers up to 10 users, with Professional and Enterprise plans starting around USD 175 and 210 per year for four concurrent calls.