A facsimile apparatus includes a first detection unit, a second detection unit, a third detection unit, and a determination unit. The first detection unit detects a line voltage in an on-hook state. The second detection unit detects a line voltage in an off-hook state. The third detection unit detects a line current in an off-hook state. The determination unit determines a line impedance based on the line voltage detected by the first detection unit, the line voltage detected by the second detection unit, and the line current detected by the third detection unit.

The facsimile apparatus of the present invention, and the method of controlling the same, switches a connection between a telephone device and a telephone line between connected and cut off, has a power supply for supplying power to the telephone device, and, in a state where the telephone device and the telephone line are connected and supply of power from the power supply to the telephone device is stopped, in a case that an off-hook of the telephone device is detected by a detection unit for detecting an off-hook and an on-hook of the telephone device, controls to start supply of power from the power supply to the telephone device.

Disclosed is a facsimile communication device, including: a line voltmeter that measures a voltage of a line used for a facsimile communication; and a hardware processor that: detects a predetermined change in the voltage of the line, in the facsimile communication; and judges whether a facsimile device of an opposite side opens the line or not according to whether the predetermined change is detected.

The facsimile apparatus of the present invention, and the method of controlling the same, switches a connection between a telephone device and a telephone line between connected and cut off, has a power supply for supplying power to the telephone device, and, in a state where the telephone device and the telephone line are connected and supply of power from the power supply to the telephone device is stopped, in a case that an off-hook of the telephone device is detected by a detection unit for detecting an off-hook and an on-hook of the telephone device, controls to start supply of power from the power supply to the telephone device.

A facsimile apparatus includes a storage unit, a first detection unit, and a second detection unit. The storage unit stores a parameter based on a connection standard of a telephone-line connected to the facsimile apparatus, and an apparatus direct-current resistance of the facsimile apparatus. The first detection unit detects a first voltage that is a voltage at a line-open time of a telephone line connected to the facsimile apparatus. The second detection unit detects a second voltage that is a voltage at a line-capture time of the telephone line. By using the first voltage, the second voltage, the parameter, and the apparatus direct-current resistance, a voltage to be a threshold for determination of line capture is determined. By using a voltage detected from the telephone line and the voltage to be the threshold determined by the first determination unit, whether the telephone line is captured is determined.

The present invention provides a technique that enables an image communication apparatus capable of performing voice communication and T.30 in-band FAX communication over the IP network to positively detect a CNG signal and achieve switching to FAX reception in the answerphone connection mode and the FAX/TEL-switching mode. The communication apparatus includes a MODEM that controls facsimile communication and a SLIC that controls a telephone. A selector includes switches for connecting the IP network and the MODEM, and switches for connecting the IP network and the SLIC. A CPU controls the switches of the selector such that signals from the IP network are supplied to both of the MODEM and the SLIC.

An image forming apparatus includes a first connection portion, a second connection portion, a communication processing portion, a switch processing portion, and a connection determination processing portion. To the switch processing portion, the first connection portion and the second connection portion are connected in parallel. The switch processing portion breaks a communication path between the second connection portion and the switch processing portion when the facsimile communication process is executed by the communication processing portion. The connection determination processing portion, when a predetermined determination start condition is satisfied, causes the switch processing portion to break the communication path, and then when a predetermined line voltage is applied to the switch processing portion, determines that a connection between the first connection portion and the public switched telephone network is normal.

Disclosed is a facsimile communication device, including: a line voltmeter that measures a voltage of a line used for a facsimile communication; and a hardware processor that: detects a predetermined change in the voltage of the line, in the facsimile communication; and judges whether a facsimile device of an opposite side opens the line or not according to whether the predetermined change is detected.

The present invention is intended to inhibit off-hook using a hook key in an operation unit to make a caller ID function stably usable in an image communication apparatus connectable to a telephone line and having a caller ID display function. According to one embodiment, the image communication apparatus includes an off-hook unit configured to perform the off-hook using the hook key in the operation unit, a detection unit configured to detect polarity reversal of a telephone line, a receiving unit configured to receive an information service signal, which arrives via the telephone line, after the detection unit has detected the polarity reversal, and a control unit configured to perform control to inhibit the off-hook by the off-hook unit based on the detection of the polarity reversal by the detection unit.

An information processing apparatus capable of preventing a user from unnecessarily taking a wasteful action. Whether a communication line is connected to the information processing apparatus and an off-hook state in the information processing apparatus are detected. Whether to turn on a display unit is controlled. When connection of the communication line to the information processing apparatus and the off-hook state are detected the display unit is controlled to turn on. When non-connection of the communication line to the information processing apparatus and the off-hook state are detected, the display unit is controlled not to turn on.