off-hook voice announce - Computer Definition
A key telephone system (KTS) feature that enables the system attendant to announce another incoming call even if the station user is off-hook and engaged in another call. In some implementations, the announcement is through the telephone speaker, with the station microphone muted so that the other party does not hear the announcement. In other implementations, the announcement is through the handset receiver so that the other party is not muted, as the muting is noticeable. See also KTS.