Voice mail exchange with a message recorder divided into sectors for groups of voice mail telephone sets

A voice mail exchange for a plurality of voice mail telephone sets grouped into first through N-th groups, in which N represents a predetermined number, an n-th group of said first through said N-th groups comprising an n-th group of telephone sets from among said voice mail telephone sets, where n represents one of 1 to N, both inclusive, said voice mail exchange comprising a message recorder for recording messages and switching means for switching transmission of said messages between said message recorder and the telephone sets of said first through said N-th groups, wherein:

• said message recorder comprises first through N-th memory sectors in one-to-one correspondence to said first through said N-th groups so that only an n-th memory sector of said first through said N-th memory sectors is used for the messages originating at and destined for said n-th group of telephone sets:
• said switching means judging, when said n-th memory sector should be used for storage of one of said messages that is for said n-th group of telephone sets of said n-th group, whether or not said n-th memory sector includes an idle portion for storage of said one of said messages, said predetermined number being a first predetermined number, wherein said switching means comprises:
• first through M-th transmission ports put in a port busy state of transmitting said messages to and from said first through said N-th memory sectors, where M represents a second predetermined number related to said first predetermined number in accordance with predetermined office data;
• control means for producing a switching signal in accordance with said office data and for producing control signals in accordance with said office data and in compliance with port state information and recorder state information indicative of whether or not said first through said M-th transmission ports are in said port busy state and whether or not said first through said N-th memory sectors individually include said idle portion, said control signal selectively putting said first through said M-th transmission ports in said port busy state;
• and
• switchboard means responsive to said switching signal and said control signals for switching between said first through said N-th memory sectors and the telephone sets of said first through said N-th groups through said first through said M-th transmission ports.