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: The present invention relates to a system (FDD) for driving such a magnetic disc as a floppy disc, in which, in a stand-by mode where recording or reproducing operation is not carried out, a magnetic head is moved to a track position in the vicinity of the innermost peripheral part of the disc or the disc is intermittently rotably driven so that an adsorbent phenomenon can be prevented from taking place between the magnetic head and the disc and even in the case of occurrence of such a adsorbent phenomenon, the magnetic head or disc can be easily released from such adsorbent binding, thus preventing any destruction of information recorded on the disc.

Abstract: A telephone system which allows external releasing of a holding state set by a holding operation of a telephone set. A signal receiving circuit of the system receives a holding-state releasing signal such as a DTMF signal or the like sent from a central office line to release the hold state of the telephone set on the basis of an output of the circuit.

Abstract: A method of setting operating data is provided wherein a display, at a predetermined key telephone set, indicates the capabilities of all sets of the system to perform the various functions of which the system's key telephones are capable. The display indicates three conditions: whether all telephones are capable of performing the indicated function, whether no telephones are capable of performing the function, or whether at least one but not all telephones are so capable. The setting of operating data is facilitated by this display. Changes made in operating data are not permanent until a setting key is depressed. Before that, the original operating data may be recovered.

Abstract: This system is a key telephone system of a type setting operating data for controlling the operations of respective key telephone sets and the entire system by using the keys of the key telephone sets. This key telephone system has a plurality of key telephone sets and a main unit, and the main unit has first and second memories for storing the operating data. The main unit takes the first mode for operating the system in accordance with the operating data of the first memory and the second mode for setting the operating data. The second memory stores the reference operating data and transfers the data into the first memory as required.

Abstract: A method for testing communication paths of an electronic exchange which has at least one pair of time-sharing communication highways and in which a plurality of port circuits are connected to one another in time-sharing fashion through the first and second communication highways. In the method, test data are allotted to prescribed time slots and are transferred to receiving means through the communication highways. The test data are fed back from the port circuits whose hybrid transformers are in non-matching state, then allotted to different time slots, and finally transferred to a dual tone multi-frequency signal receiver through the communication highways.