KEY TELEPHONE SYSTEM

PURPOSE: To control the output to a facsimile equipment by enabling the efficient use of a facsimile equipment and displaying the annexed information on received image data on the display part of a key telephone set. CONSTITUTION: At the time of the transmission from a facsimile equipment 7, lines except a facsimile line 5 A are used. In the case of a reception, the contents is received by a reception modem 63-1, the contents is analyzed by a protocol analysis part 63 and the contents is stored in an information data storage part 64 storing annexed information and an image data storage part 65. Subsequently, the efficient use of the facsimile equipment 7 is enabled by the the transmission during a reception and the reception during the transmission by using a transmission modem 63-2 and transfering data to the facsimile equipment 7. The contents of the image data storage part 65 can be reoutputted to the facsimile equipment 7 through the protocol analysis part 63 by displaying the information such as opposite party information, etc., on a key telephone set 4x as necessary based on the contents of the annexed information of the information data storage part 64.