The 3CX Phone System is a software private branch exchange based on the SIP (Session Initiation Protocol) standard to allow calls via the public switched telephone network (PSTN) or via Voice over Internet Protocol (VoIP) services.

In 2006, 3CX released the 3CX Phone System as a free IP PBX for use in a Microsoft Windows environment.

[2][3][4][5] In the following years, 3CX made a number of acquisitions including eWorks technologies in 2013,[6] the Elastix project and PBX in a Flash in 2016, and Askozia in 2017.

[7] In September 2016, 3CX announced a partnership with BT Wholesale SIP Trunking platform to serve resellers.

[15] The hack was linked to the same North Korean operators that compromised the Trading Technologies app.

[18] On 8 July 2016, 3CX announced that it has become an official sponsor of Cypriot football club, APOEL FC of Nicosia, Cyprus for a period of 3 years.