Abstract: In a modem pooling system for enabling selective connection of a plurality of data terminal units 5.sub.1 to 5.sub.n to a modem 9, each of the data terminal units 5.sub.1 to 5.sub.n is detected as to whether active or inactive; one data terminal (e.g. 5.sub.1) is selected as a responsive terminal unit from among the data terminal units determined to be active in accordance with a predetermined priority order; and the modem 9 is connected to the selected responsive terminal unit (e.g. 5.sub.1), prior to an incoming call response of the modem 9.

Abstract: In a key telephone system in which a plurality of data terminals 371 . . . 37n such as personal computers are connected to a key service unit 1 connected to a plurality of telephone lines 251 . . . 25m, a modem 43 is pooled so as to be usable in common for the plural data terminals 371 . . . 37n. In response to a called party number signal from the Telephone line (e.g. 251), the key service unit 1 selects a single data terminal among the data terminals 371 . . . 37n now being in standby status, and closes a communication channel between the selected data terminal (e g 371) and the modem 43, so that a status equivalent to that where the selected data terminal 371 and the modem 43 are directly connected to each other can be established. Thereafter, the key service unit 1 indicates a called party number signal reception to the modem 43, and the modem 43 transmits a call to the selected data terminal 371.

Abstract: In a key telephone system in which a plurality of data terminals 37l . . . 37n such as personal computers are connected to a key service unit 1 connected to a plurality of telephone lines 25l . . . 25m, a modem 43 is pooled so as to be usable in common for the plural data terminals 37l . . . 37n. In response to a called party number signal from the telephone lines (e.g. 25l) in dial-in service, the key service unit 1 selects a single data terminal designated by an extension telephone designation signal in dial-in service from among the data terminals 37l . . . 37n, and closes a communication channel between the selected data terminal (e.g. 37l) and the modem 43, so that a status equivalent to that where the selected data terminal 37l and the modem 43 are directly connected to each other can be established. Thereafter, the key service unit 1 indicates a called party number signal reception to the modem 43, and the modem 43 transmits a call to the selected data terminal 37l.

Abstract: In a key telephone system in which a plurality of data terminals 37l . . . 37n such as personal computers are connected to a key service unit 1 connected to a plurality of ISDNs 23l . . . 23m, a terminal adapter (TA) 41 is pooled so as to be usable in common for the plural data terminals 37l . . . 37n. In response to a setup signal from an ISDN (e.g. 23l), the key service unit 1 selects a single data terminal designated by a subaddress included in the setup signal from among the data terminals 37l . . . 37n, and closes a communication channel between the selected data terminal (e.g. 37l) and the TA 41, so that a status equivalent to that where the selected data terminal 37l and the TA 41 are directly connected to each other can be established. Thereafter, the key service unit 1 transmits a setup signal to the TA 41, and the TA 41 transmits a call to the selected data terminal 37l.

Abstract: A dial information character code which designates an address of a remote facsimile apparatus is included in an input character code and the input code or a picture signal corresponding thereto is sent to an addressed remote facsimile apparatus corresponding to the dial information character code.