JP2000125065A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device which can reduce the consumption of a line current and has no risk of causing malfunction of an exchange. SOLUTION: Photocouplers A1 and B1 for line polarity detection which are connected in parallel and have mutually opposite polarities are switched over at a constant cycle by a pulse generating circuit (OSC) 121. At the start of transmission, the output states (combination of pulses or high-level outputs) of the photocouplers A1 and B1 detected through buffers 122 and 123 are stored as line polarity data in a RAM and then the stored line polarity data are compared with the line polarity data outputted by the photocouplers A1 and B1 to detect whether or not the output change of the side which has bee in the high level at the start of the transmission is present, thereby discriminating the change of the line polarity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a communication device that performs a predetermined communication process and performs a predetermined communication control according to a change in line polarity, a control method thereof, and a computer-readable recording medium storing the control program.

[0002]

2. Description of the Related Art In analog communication lines, tone or pulse dial signals as well as line polarity have been used for a long time as information for line switching. For example, polarity reversal detection is used for determining incoming and outgoing calls, etc. In recent years, it has also played an important role in various information notification services (outgoing telephone number notification and other information notification services) in the telephone network.

A communication device such as a facsimile device can be no exception as long as it is connected to an analog line.
In order to perform various communication controls, it is necessary to detect the polarity of the line and determine the operation based on the result.

For this reason, in a conventional communication device such as a facsimile device, a polarity detection circuit is provided in an NCU (network control device). In many cases, the circuit is driven and its output is used to determine the line polarity.

[0005]

For example, communication control related to line polarity in a facsimile machine includes:
When performing transmission, if the other party releases the line during transmission, an operation of detecting the polarity reversal of the circuit, immediately stopping the transmission, and opening the line is mentioned.

In order to detect that the other party has released the line, a circuit using the above-described photocoupler has been conventionally used. However, in the method in which the photocoupler is always driven as described above, the line current is always used for polarity detection. , And a DC loop is formed, which may cause a malfunction of the exchange.

An object of the present invention is to solve the above-mentioned problems, to provide a communication device which can reduce line current consumption and does not cause a malfunction of a switch.

[0008]

According to the present invention, there is provided a communication apparatus connected to a line for performing predetermined communication processing and performing predetermined communication control according to a change in line polarity. In a computer-readable recording medium storing the control method and the control program, a polarity detection means for detecting a line polarity is driven at regular intervals by a pulse drive signal, and the polarity detection is performed at a predetermined timing during communication. The line polarity data output from the means is stored in the storage means. During the communication, after the predetermined timing, the stored line polarity data is compared with the line polarity data output by the polarity detection means to change the line polarity. Is identified, and a predetermined communication control is performed based on the identification result.

According to the above configuration, the line polarity data output by the polarity detection means at a predetermined timing during communication is stored in the storage means, and thereafter, the stored line polarity data and the line polarity data output by the polarity detection means are output. Are compared to identify a change in line polarity. According to this configuration, it is possible to reduce the consumption of the line current by driving the polarity detection means at regular intervals, and since a DC loop is not formed, the line polarity can be prevented without causing the switch to malfunction. Can be identified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of a facsimile apparatus employing the present invention. In FIG. 1, reference numeral 2 denotes a CPU that controls the operation of the entire apparatus. The CPU 2 is supplied with an output clock of an oscillator 1 as a reference clock.

The CPU 2 is connected to a ROM 4, a RAM 5, a timer 3, a PIO 7 (peripheral I / O), and a modem 6 by a data and address bus.

The modem 6 is composed of a well-known FAX modem chip or the like.
1, connected to L2 to perform facsimile communication.

An operation unit (OPCN) connected to the PIO 7
T) 10 performs detection of key input of a keyboard on the operation panel, LCD display, and lighting control of LEDs in accordance with a command from the CPU 2.

Reference numeral 8 denotes an image reading unit (R), which comprises a document conveying system, an optical scanner of a predetermined system, and the like. Motor drive control of the document conveying system of the image reading section 8 and input / output of read image data are performed via the PIO 7.

Reference numeral 9 denotes a recording section (W), a recording paper transport system,
It comprises a recording mechanism of a predetermined system (for example, a bubble jet system or a laser beam system). The control of the recording paper transport motor and the input and output of image data to be recorded are performed via the PIO 7.

Reference numeral 11 denotes a speaker (SPK), and CP
In accordance with the instruction from U2, an error sound or the like is output as sound from the PIO 7. The output voice is a voice synthesized by a voice synthesis circuit (not shown), a voice recorded by a recording unit (not shown), a buzzer sound generated by an oscillator (not shown), or the like.

The NCU 12 has an analog line L1,
It includes a circuit for switching connection between L2, telephone (TEL) 20, and modem 6 for facsimile communication, and a circuit for detecting line polarity described later. The CPU 2 controls the operation of the NCU 12 via the PIO 7.

FIG. 2 shows the circuit configuration of the NCU 12 of FIG. 1 in detail.

In FIG. 2, a telephone line is connected to terminals L1 and L2, and a telephone (TEL) is connected to terminals T1 and T2.
20 are connected. The modem 6 is connected via an interface circuit CP1 including a transformer and a capacitor.

The relay CML connects the line to the modem side or
A relay for switching connection to the connection terminals T1 and T2 (TEL) of the telephone set 20, and the relay CML is a CPU
2, the switching operation is performed based on the switching signal transmitted through the PIO 7.

Reference numerals A1 and B1 denote photocouplers for detecting the polarities of telephone lines, which are connected in parallel with opposite polarities as shown in the figure, and are connected to lines L1 and L2 via resistors R1 and R2.
Inserted between them. In the present invention, the photocouplers A2 and B2 and the pulse generation circuit (OSC) are not always driven.
The switching is performed at regular intervals by the switch 121. A pulse generation circuit (OSC) 121 causes the LED sections of the photocouplers A2 and B2 to emit light by a pulse signal having a predetermined waveform such as a rectangular wave, and intermittently switches the line in which the photocouplers A2 and B2 are inserted.

The protection varistor V1 is connected in parallel to the parallel circuit of the photocouplers A1 and B1 (and the phototransistor portions of the photocouplers A2 and B2) to the series circuit of the resistor R2.
Is inserted.

The collector outputs of the photocouplers A1, B1 are supplied to buffers (CNT-A, CNT-B) 122, 12
3 is input to the PIO 7, whereby the CP of FIG.
U2 detects a change in line polarity.

Hereinafter, photocouplers A1, B1, A2, B
Operation 2 will be described. The positive and negative polarities of the lines L1 and L2 are not generally guaranteed, but are determined by the connection of the telephone line (for example, connection work during construction). In the present embodiment, A1 is assumed on the assumption that L1 is positive and L2 is negative during standby.
The 1 and B1 outputs will be described with reference to FIG.

FIG. 5 shows a change in pulse output of the photocouplers A1 and B1 when the line L1 is positive and L2 is negative.

First, in the case of the above-mentioned polarity setting, in the normal state, that is, when there is no call from the line,
Is not communicating on both the on-hook and facsimile (relay CML is off), the photocoupler B1 is non-conductive, the collector output is at H level, and the photocoupler A
1 is a pulse output according to the lighting cycle of the pulse generation circuit (OSC) 121 (FIG. 5A: non-communication / communication state).

The telephone 20 goes off-hook or the relay C
Even when the ML is turned on and facsimile communication is started, the state remains the same until a call connection is established (FIG. 5).
(B): Call / communication start).

When a call is made from the line, an AC signal (call signal) of a predetermined frequency is generated between the lines L1 and L2,
As a result, both the photocouplers A1 and B1 alternately output pulses during the input period of the calling signal having the predetermined frequency.

In response, the facsimile apparatus or telephone 20 responds, that is, in the case of a facsimile, the relay CML is turned on by a call signal detection circuit (not shown). When the call connection is established due to the hook-off, the polarities of the lines L1 and L2 are inverted, whereby the output states of the photocouplers A1 and B1 are inverted (FIG. 5C). This is the same when the call connection is established from the call / communication start state in FIG.

Thereafter, while the line is connected to the other party, the photocoupler B1 outputs a pulse and the collector of the photocoupler A1 outputs an H level. However, if the other party disconnects the line in the off-hook state, the polarity of the line is lost. Are reversed, the photocoupler B1 returns to the H level, and A1 returns to the pulse output (FIGS. 5D and 5E). FIG. 5D shows a case where the telephone 20 is off-hook, that is, when the other party hangs up from the talking state. 5 (E) shows the case where the telephone 20 is on-hook, that is, the other party has disconnected from the facsimile communication state).

As described above, since the combination of the output states of the photocouplers A1 and B1 changes depending on the polarities of the lines L1 and L2, the polarity inversion can be determined by detecting the combination of the output states. That is, at a certain timing during communication, the photocouplers A1 and B
1 is stored in the RAM 5 and a change in the output state of the photocouplers A1 and B1 is detected thereafter, whereby a change in the polarity can be determined.

For example, in the process of disconnecting a line from a partner station during facsimile communication described in the section of the conventional example, as shown in the processing of FIGS. Line polarity (buffer 1
22 and 123) are stored in the RAM 5, and it is intermittently determined based on the polarity data stored in the RAM 5 whether or not the polarity has been reversed by an interrupt processing routine during the transmission operation, and the polarity has been reversed. As soon as it is determined, the transmission operation can be stopped and the error can be terminated.

FIGS. 3 and 4 show the control executed by the CPU of FIG. 1 at the time of transmission. The illustrated procedure is a program of the CPU 2 in the ROM 4 (or other storage media: these storage media are the storage media of the present invention). (Corresponding to a medium).

In step S1 of FIG. 3, when the line is connected to the transmission destination and the apparatus starts an image transmission operation, in step S2, a document is inserted in response to pressing of a transmission button on the keyboard on the operation unit 10, and an LCD monitor is displayed. Display on,
In addition, various initializations required for image transmission are performed.

Next, in step S3, the polarity of the line,
That is, the output state of the buffers (CNT-A, CNT-B) 122 and 123 for outputting the polarity data of the line in FIG. At this time, the storage format in the RAM 5 only needs to store a flag or a binary constant corresponding to whether the output of each buffer is a pulse output or a fixed level (high level).

Then, in a loop of steps S4 and S5, facsimile image transmission (processing such as image reading, sampling, encoding, etc. is known, so that the description is omitted). When facsimile transmission is completed, in step S6, Reset processing such as discharging the original and turning off the LCD display is performed.

The loop of steps S4 and S5 is shown in FIG.
It is implemented by interrupt processing as shown in (1). The interrupt routine shown in FIG. 4 is executed every time one byte of image data is transmitted.
256 times per session (approximately 53 kbps).

In step M1 of FIG. 4, the output states of the buffers (CNT-A, CNT-B) 122 and 123 are input, and in step M2, in step M1 already stored in the RAM in step S3 of FIG. If the states match with the input polarity data, it is determined that the polarity is not inverted, and the process proceeds to step M3. Step M2 above
In the case where the line L1 is positive and the line L2 is negative as shown in FIG. 5, it is easier to compare whether or not the pulse output side is not the same, that is, the CNT-B side in FIG. It also gives good results.

On the other hand, in step M2, the buffer 1
The output states of the outputs 22 and 123 are compared with the polarity data input in step M1, and if the states do not match (unless the CNT-B side matches in FIG. 5), it is determined that the polarity is inverted, and the process proceeds to step M4.

If the polarity is not inverted, one byte of image data is transmitted via the modem 6 in step M3. On the other hand, in the case of polarity reversal, the process proceeds to step M4, where error processing is performed. This error processing is the same as the error processing based on disconnection of the other party in the conventional facsimile machine. Here, line release, LCD error display, motor off, error sound output, software reset, etc. are performed. .

As described above, since the polarities of the lines are not generally guaranteed, when the polarities of the lines L1 and L2 are reversed, the change in the output state of the photocouplers A1 and B1 shown in FIG. The opposite is true. Therefore, contrary to the above, when the line L1 is negative and L2 is positive, the buffer 122
The polarity inversion may be determined by focusing on the side of (CNT-A).

Note that, as described above, the buffer 122 (CN
In order to detect the polarity reversal by inspecting the non-pulse output side of TA-A) or the buffer 123 (CNT-B), the initial polarity of the line is detected in advance when the device is reset. Alternatively, the buffer to be inspected in step M2 may be determined based on the detection result of the polarity state in step S3 in FIG. 3 (for example, the non-pulse output side in step S3 is inspected in step S2). Do).

Although a single facsimile apparatus has been described above as an example, the present invention is not limited to a facsimile but can be applied to any apparatus for detecting the polarity of a communication line. For example, it goes without saying that the technology of the present invention can be applied to an information processing device such as a personal computer having a built-in modem for facsimile or data communication, a line interface portion of a digital copying machine having a communication function, and the like. The control shown in FIG. 4 may be executed by a CPU for communication control or main control of these devices. The control procedure shown in FIGS. 3 and 4 can be stored not only in the ROM but also in a floppy disk, a hard disk, various memory cartridges and cards.

[0045]

As is apparent from the above, according to the present invention, the line polarity data output from the polarity detection means at a predetermined timing during communication is stored in the storage means.
Since a configuration is employed in which the change in line polarity is identified by comparing the stored line polarity data with the line polarity data output by the polarity detection unit, the line detection unit is driven at regular intervals, thereby Current consumption can be reduced, and since a DC loop is not formed, a change in line polarity can be identified without causing a malfunction of the switch, and predetermined communication control can be performed based on the result. There is an excellent effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a facsimile apparatus employing the present invention.

FIG. 2 is a circuit diagram showing a configuration of a main part of the NCU in FIG. 1 in detail.

FIG. 3 is a flowchart illustrating a flow of communication control of a CPU in FIG. 1;

FIG. 4 is a flowchart illustrating a flow of communication control of a CPU in FIG. 1;

5 is a table illustrating an output state of a polarity detection buffer of FIG. 2 and a state of a line polarity;

[Explanation of symbols]

 3 Timer 4 ROM 5 RAM 6 Modem 7 PIO 8 Image reading unit 10 Operation unit 20 Telephone (TEL) 121 Pulse generation circuit 122, 123 Buffer (CNT-A, CNT-B) A1, A2 Photocoupler B1, B2 Photocoupler

Claims (3)

[Claims] 1. A communication device connected to a line for performing predetermined communication processing and performing predetermined communication control in accordance with a change in line polarity, comprising: a polarity detection unit for detecting a line polarity; Pulse driving means for driving at regular intervals by a pulse driving signal; storage means for storing line polarity data output from the polarity detection means at a predetermined timing during communication; and Control means for identifying a change in line polarity by comparing the line polarity data stored in the storage means with the line polarity data output by the polarity detection means, and performing predetermined communication control based on the result. A communication device comprising: 2. A control method for a communication device connected to a line for performing predetermined communication processing and performing predetermined communication control in accordance with a change in line polarity. At a predetermined time during communication, and at a predetermined timing during communication, the line polarity data output from the polarity detecting means is stored in the storage means. During the communication, after the predetermined timing, the stored line polarity data, A control method for a communication device, comprising: identifying a change in line polarity by comparing line polarity data output by a polarity detection unit; and performing predetermined communication control based on the identification result. 3. A computer-readable recording medium which is connected to a line and stores a control program for a communication device which performs a predetermined communication process and performs a predetermined communication control according to a change in the line polarity. A control step of driving the polarity detection means to be detected at regular intervals by a pulse drive signal; a control step of storing line polarity data output from the polarity detection means in a storage means at a predetermined timing during communication; After the predetermined timing, the stored line polarity data is compared with the line polarity data output by the polarity detecting means to identify a change in the line polarity, and a predetermined communication control is performed based on the identification result. A recording medium storing steps.