Abstract: A communication control device for controlling communication performed over a communication line includes a voltage-value acquirer for acquiring a value of a line-to-line voltage of the communication line in an on-hook state, a first determiner for determining whether the voltage value is continuously equal to or lower than a threshold voltage for a first predetermined duration, a current-value acquirer for acquiring a value of a current flowing through the communication line in an off-hook state when the voltage value is continuously equal to or lower than the threshold voltage for the first predetermined duration, a second determiner for determining whether the current value is continuously equal to or smaller than a threshold current for a second predetermined duration, and a disconnection determiner for determining that the communication line is disconnected when the current value is continuously equal to or smaller than the threshold current for the second predetermined duration.

Abstract: A communication control device for controlling communication performed over a communication line includes a voltage-value acquirer for acquiring a value of a line-to-line voltage of the communication line in an on-hook state, a first determiner for determining whether the voltage value is continuously equal to or lower than a threshold voltage for a first predetermined duration, a current-value acquirer for acquiring a value of a current flowing through the communication line in an off-hook state when the voltage value is continuously equal to or lower than the threshold voltage for the first predetermined duration, a second determiner for determining whether the current value is continuously equal to or smaller than a threshold current for a second predetermined duration, and a disconnection determiner for determining that the communication line is disconnected when the current value is continuously equal to or smaller than the threshold current for the second predetermined duration.

Abstract: An image forming apparatus includes, a network interface for connecting the image forming apparatus to a network as a network terminal, an electronic mail communication control unit for communicating an electronic mail with another network terminal through said network interface, a memory for storing an address of a predetermined network terminal, a sensor for detecting an abnormal condition of the image forming apparatus, a controller for producing the electronic mail according to the address stored in the memory, and wherein the electronic mail communication control unit sends an electronic mail produced by the controller to the predetermined network terminal when the sensor detects an abnormal condition such as when the sensor detects a paper jam, toner empty and paper-out.

Abstract: A first ISDN terminal transmits a receipt result information report to a second ISDN terminal via a D-channel after the first ISDN terminal receives a data from the second ISDN terminal. The data comprises image information. The image information is transmitted via a B-channel. The receipt result information report indicates a result of receiving of the image information for confirmation by the second ISDN terminal of the receiving at the first ISDN terminal. The D-channel is used for transmitting predetermined protocol information between the ISDN terminals. The predetermined protocol information includes an identification information. The identification information is used for controlling a connection between the ISDN terminals.

Abstract: A facsimile machine in conformity with an information services digital network (ISDN) basic interface having a single signal channel and two information channels, includes a communication circuit, which has a first device of exchanging transmission and reception image signals with an ISDN through one of the two information channels (B-channels), a second device of exchanging the transmission and reception image signals with the ISDN through the other information channel, a third device of separately establishing the two information channels through the single signal channel, and a fourth device of controlling the first and second devices to independently exchange the transmission and reception image signals with the ISDN in parallel.