DOS-based card-type voice mail system

A card-type voice mail system connected to a key telephone system, said voice mail system comprising:

• a key telephone system interface connected to a universal slot of the key telephone system for interfacing with said key telephone system;
• a codec connected to said key telephone system interface for digitizing analog data received through said key telephone system interface from said key telephone system, and for converting the digitized data into analog data to supply said analog data to said key telephone system through said key telephone system interface;
• a voice mail card connected to said codec and to said key telephone system interface for compressing data digitized from said codec, and for restoring the compressed data to supply the restored data to said codec;
• a storage device connected to said voice mail card, to said codec, and to said key telephone system interface for storing data compressed by said voice mail card, and for supplying the stored data to said voice mail card;
• a memory for loading a universal operating system;
• and
• a controller connected to said memory, to said voice mail card, to said codec, and to said key telephone system interface for controlling said card-type voice mail system in accordance with said loaded universal operating system.