A group of users can be created with a purpose of receiving voice announcements through the speaker of a telephone set, but it has to be in the waiting mode.
This is a Voice over Internet Protocol (VoIP) and streaming media service based on the Session Initiation Protocol (SIP) by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers equipped with SIP-based private branch exchange (IP-PBX) and Unified Communications facilities