JP3008708B2 - A communication device that is connected to a telephone line by branching a telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device which is connected to a telephone line by branching to a telephone line.

[0002]

2. Description of the Related Art Conventionally, telephone lines are used as data communication lines, such as facsimile machines and telex communication lines, in addition to telephones. With the spread of data communication, facsimile machines and the like have become widely used in ordinary households. A dedicated telephone line is not prepared for data communication, and both telephone and facsimile machines can communicate with one telephone line. Use is increasing.

[0003] Both facsimile machines and telex machines communicate data after establishing communication according to a similar protocol. Here, the relationship between a telephone and a communication device will be described using a facsimile machine as an example. Simply connecting the telephone and the facsimile device to the telephone line in parallel, if there is an incoming call, regardless of whether the telephone is off-hook, the facsimile device starts responding,
Since the communication sound of the protocol is turned on, it is not possible to branch connect the facsimile machine to the telephone.

Conventionally, an attached telephone or a sub telephone can be connected to a facsimile apparatus, and communication between the telephone and the facsimile can be performed by an NCU (network control circuit) of the facsimile apparatus. As the communication mode, generally, a manual incoming call mode and an automatic incoming call mode are known. In the manual incoming call mode, the incoming call at the telephone is prioritized, and when the incoming call is a facsimile, the operator who has gone off-hook switches to the facsimile reception. There are various types of automatic call reception modes. When a call is received, the facsimile apparatus monitors a facsimile identification signal, for example, a CNG signal, and performs a facsimile procedure when the CNG signal is detected within a predetermined time. However, if no CNG signal is detected, the telephone is placed under the control of the facsimile machine, such as calling the attached telephone and the child telephone.

[0005] Therefore, a person who has an existing telephone,
In order to install a facsimile apparatus by sharing the same line, the facsimile apparatus must be installed at the place where the telephone is located, and an attached telephone must be used instead of the existing telephone. In order to install the facsimile machine in a place different from the place where the telephone is placed, there is a problem that the line of the child telephone must be extended, and the child telephone must be purchased separately.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to realize a communication device capable of branch connection to a telephone line.

[0007]

SUMMARY OF THE INVENTION The present invention is a communication device which is connected to a telephone line by branching with a telephone, wherein the telephone is directly connected to a telephone line connected to the communication device, and a hook of the telephone is provided. Off-hook detection means for detecting a state, identification signal detection means for detecting an identification signal, and silence detection means for detecting continuation of a silence state, wherein the identification signal is output when the off-hook detection means detects an off-hook of the telephone. The detection means and the silence detection means are operated.

[0008]

According to the present invention, the off-hook / on-hook of the branch telephone can be detected irrespective of the operation of the communication device by using the off-hook detecting means for detecting a change in the line voltage of the telephone line. Further, since the detection of the identification signal or the silent state is performed after the off-hook of the branch telephone, the transmitting side does not cause an unpleasant signal sound to be transmitted.

[0009]

FIG. 1 is a block diagram of a main part of an embodiment in which the present invention is applied to a facsimile apparatus. In the figure, 1 is a line, 2 is a branch telephone, 3 is a facsimile connection terminal,
4 is a facsimile machine, 5 is a slave telephone connection terminal, 6 is an attached telephone connection terminal, 7, 8 are off-hook detection circuits,
10 is a changeover switch, 11 and 12 are transformers, 13 is a modem, 14 is a dial circuit, 15 is an incoming call detection unit, 16 is a voltage monitoring unit, 17 is a calling voltage generation unit, 18 is a display unit,
9 is an operation unit, 20 is a ROM, 21 is a RAM, 22 is a timer unit, 23 is a document reading unit, 24 is a recording unit, 25 is a speaker, 26 is a silence detection unit, 27 is a CNG detection unit, and 28 is a DTMF detection unit. , 29 are main control units (CPU).

A line telephone 1 is connected to a branch telephone 2, and the line 1 to which the branch telephone 2 is connected
A facsimile device 4 is connected in parallel at the connection terminal 3. The modem 13 of the facsimile machine 4 is connected to the line 1 via the transformer 11 and the changeover switch 9. The slave telephone and the accessory telephone are connected to the slave telephone connection terminal 5 and the accessory telephone connection terminal 6, respectively. With the changeover switch 9,
The connection of the line 1 to the incoming call detection unit 15 and the modem 13 is switched, and the changeover switch 10 switches the slave telephone and the attached telephone to the line 1 or the ringing voltage generation unit 17. The ringing voltage generator 17 is configured as a DC voltage source,
When the attached telephone and the sub telephone are disconnected from the telephone line, a DC voltage is supplied to them so that the off-hook / on-hook can be detected by the off-hook detection circuits 7 and 8. The changeover switches 9 and 10 are controlled and switched by the CPU 29.

The dial circuit 14 transmits a dial pulse corresponding to the telephone number of the other party when calling. The incoming call detection circuit 15 is composed of a photocoupler,
Is connected to the line 1 side, and the ON / OFF state of the phototransistor is monitored by the CPU 31 at a predetermined sampling cycle, whereby a call signal (16 Hz) of the exchange arriving on the line 1 can be detected. . The off-hook detection circuits 7 and 8 detect the off-hook state of the attached telephone and the sub telephone, respectively, and the detection results are monitored by the CPU 31. The transformer 12 transmits the tone signal from the line 1 from the transformer 12 to the modem 13 when the changeover switch 9 is switched to the incoming call detection unit 15 side.
The silent state detecting unit 26 and the CNG detecting unit 27 detect a silent state and a CNG signal. The detection of the silence state is performed when silence continues for a predetermined time, for example, 6 seconds.
Make a silent state.

The voltage monitor 16 detects the voltage of the line 1. If the branch telephone 2 goes off-hook when there is an incoming call on the line 1, the voltage of the line 1 drops.
On hook can be detected. The display unit 18 displays the status of the facsimile machine and data input from the operation unit 19. The document reading unit 23 reads a transmission document or a copy document, and the recording unit 24 prints out a reception document or copy data. The speaker 25 outputs a pseudo bell sound and a warning sound. A main control unit (CPU) 29 controls the entire facsimile machine based on control programs and fixed data stored in the ROM 20.

FIG. 4 shows a specific example of the voltage monitoring unit 16.
In the figure, 1 is a line, 2 is a branch telephone, 31 is a voltage detection unit, 32 is a voltage storage unit, and 33 is a comparison unit. The voltage detector 31 converts the detected line voltage into a digital value. The voltage storage unit 32 stores output data of the voltage detection unit 31 according to a command from a CPU (not shown). The comparison unit 33 stores the output data of the voltage detection unit 31 in the voltage storage unit 32
And outputs an H or L signal according to the comparison result. The output signal is transmitted to a CPU (not shown). For example, when there is an incoming call, the DC voltage of line 1 is 4
The voltage is about 8 V, and the voltage detector 31 converts the detected voltage into a digital value. This digital value is stored in the voltage storage unit 32 as a reference voltage of the comparison unit 33. The DC voltage of the line 1 when the telephone is off-hook is, for example, about 5 V. Therefore, if the branch telephone 2 is off-hook after an incoming call, the comparator 33 detects that the difference has exceeded the threshold, and the branch telephone 2 Off-hook can be detected. The threshold may be selected according to the situation to be detected. For example, when the line is closed in both the facsimile unit and the branch telephone, it is possible to detect a small voltage change when the branch telephone 2 is hooked on with different sensitivity from a large voltage change when off-hook. it can. Voltage storage unit 32 does not necessarily need to store data from voltage detection unit 31. As mentioned above, 48V and 5V
When a situation where the difference is large is detected, an intermediate voltage value may be stored. Also, an analog circuit such as a differential amplifier circuit may be used in correspondence with the comparison unit, and the voltage detection unit may detect the analog voltage and compare it with the comparison voltage. Good.

As described above, the voltage monitoring unit detects the line state due to the off-hook / on-hook of the branch telephone, so that it can also be detected by the off-hook detection circuit 7. In order to detect a differential change in the line voltage, for example, it is also possible to detect a voltage change within 100 msec. Alternatively, the detection may be made based on the line current. That is, if there is an incoming call and the branch telephone is on-hook, the current of the line is small. If the branch telephone is off-hook, the line current increases. Therefore, the off-hook / on-hook of the branch telephone can be detected by directly detecting the line current. The magnetic field due to the line current may be detected using a Hall element or the like. However, when detecting the line current, the detector must be provided closer to the office than the branch telephone, so it is necessary to consider the arrangement of the detector.

FIG. 2 is a flowchart for explaining one embodiment of the operation of the facsimile apparatus of FIG. The flow starts with the branch telephone priority mode selected. As described above, since the line voltage is monitored and the off-hook / on-hook of the branch telephone 2 is detected from the change, the line voltage before the incoming call is detected in S1 and the value is stored in the RAM 21. Keep it. Then, S2
Then, the bell sound is detected. With no incoming calls,
The loop from S2 to S1 is repeated to be in a standby state. When there is an incoming call, the output of the incoming call detection unit 15 is transmitted to the CPU 31, a bell sound is detected, and the process proceeds from S2 to S3. In this state, the branch telephone 2 rings a bell, and repeats the loop from S3 to S2. When the branch telephone 2 goes off-hook, the voltage of the line 1 decreases. The voltage monitoring unit 16 stores the detected voltage value in the RAM 21
, The off-hook is detected, the process exits the loop, and proceeds to S4. The detected voltage value is stored in the RAM 21. When the slave telephone or the attached telephone is off-hook, a call is made with the slave telephone or the attached telephone, and the off-hook detection circuit 7
Or 8 and the off-hook of the child or attached phone is C
Although it is detected by the PU 29, its description is omitted.

When the branch telephone 2 goes off-hook,
In the branch telephone, a call can be made, and if the incoming call is a call, the call is made. In parallel with this, the timer is started in S4, and the process proceeds from S5 to S6, where the silent state detecting section 26 and the CNG detecting section 27 detect a silent state or a CNG signal. This detection is S
5, S6, S7, and S8 are looped. The timer is set to, for example, 70 seconds,
By the time up, the flow becomes S5, S7, S
Loop 8 As described above, the timer limits the time during which the silent state or the detection of the CNG signal is performed. Since this restriction is not always necessary, it is not necessary to provide a timer. In that case, S4 and S5 can be omitted.

If the incoming call is a telephone call, since no sound or no CNG signal is detected, a telephone call is made with the branch telephone while the above-described loop is repeated. When the call ends, the branch telephone 2 is turned on and the line voltage rises. Therefore, the on-hook is detected by the voltage monitoring unit 16, and the flow ends from S8 and returns to the start.

If a silent state or a CNG signal is detected in step S6, the flow shifts to step S9, where the changeover switch 9 is switched by a command from the CPU 29, and
To close the line. Then, a transition to the facsimile procedure is performed. In order to inform the branch telephone 2 that the incoming call is a facsimile, the modem 13 is sent to the branch telephone 2 in S10.
A beep sound is sent out via. If the branch telephone 2 goes on-hook after hearing the signal sound, the process proceeds from S11 to S12.
And the facsimile procedure is performed. Note that S9
Since the line is closed by the facsimile side,
The branch telephone 2 and the facsimile machine 4 are connected to the line 1 in parallel. In this state, the line voltage has a lower value. When the branch telephone 2 is hooked on in step S11, only the facsimile apparatus is connected to the line 1, and the line voltage is higher than when a parallel load is applied. Therefore, the branch telephone 2 in S11
Can also be detected by the voltage monitoring unit 16.

In the loop of S5, S6, S7, and S8 or the loop of S5, S7, and S8, if the start button of the facsimile apparatus 4 is pressed, the facsimile procedure can be started.

When the procedure has shifted to the facsimile procedure, the receiving side sends out CED and DIS. CCITT T. 3
0, CED and DIS are transmitted up to 30 to 4
You need to do it for 0 seconds. In the present invention, CED and DIS can be sent once or twice. In the present invention, C
The facsimile procedure is shifted to the facsimile procedure after the fact that the facsimile is received is detected by the detection of NG or silence, so that the facsimile procedure can be started without any problem even if the number of CED and DIS transmissions is small. Further, even if the silent state is not detected by facsimile, the line can be quickly released after the off-hook of the branch telephone.

The steps S10 and S11 may be omitted. That is, in S9, the line is closed on the facsimile machine side, and the process immediately proceeds to the facsimile procedure in S12. When the facsimile procedure is started, the branch telephone 2 can hear the signal sound of the facsimile communication, so that it is sufficient to go on-hook at that time.

In this embodiment, if the incoming call is a facsimile when the branch telephone 2 goes off-hook in S3, the process can proceed to S9 by continuing the silence. Further, even when facsimile transmission is performed after a call by manual transmission from the transmission side, silence is continued at the time of switching to facsimile transmission, so that the process shifts to S9 and facsimile reception can be performed. In view of manual reception, it is better to omit steps S4 and S5.

FIG. 5 is a time chart for explaining an incoming call state. If there is an incoming call (CI) from the line (LINE), the line voltage drops when the branch telephone goes off-hook. From the time the line voltage drop is detected, a silent state or a CNG signal is detected.
As shown in the X loop A, when the CNG signal is detected, the procedure shifts to the facsimile procedure.

FIG. 3 is a flow chart for explaining another embodiment of the operation of the facsimile apparatus of FIG. The flow starts with the branch telephone priority mode selected. Steps similar to those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. In this embodiment, when the off-hook of the branch telephone 2 is detected due to a decrease in the line voltage in S3, the process proceeds to S9, where the changeover switch 9 is switched by a command from the CPU 29, and the line is closed by the transformer 11. I do. Thereafter, S6, S7 and S8 are looped to detect a silent state or a CNG signal. This detection is performed by the silence detecting unit 26 and the CNG detecting unit 27 by transmitting the tone signal from the transformer 11 via the modem 13. In this embodiment, S4 and S5 described in FIG.
Is not used, but it goes without saying that this timer may be provided. In S6, a silent state or CN
When the G signal is detected, the flow shifts to S10 and subsequent steps described in FIG.

In the case of the embodiment of FIG. 3, in the time chart of FIG. 5, as shown in FAX loop B, when the branch telephone goes off-hook, the FAX loop starts up and starts detecting a silent state or a CNG signal. I do.

In the above description of the embodiment, the branch telephone priority mode has been described. However, it is needless to say that the conventional automatic reception mode and manual reception mode may be provided together and selected. is there.

[0027]

As is apparent from the above description, according to the present invention, a facsimile apparatus can be connected in parallel to a branch telephone, so that the facsimile apparatus can be connected regardless of the installation position of the telephone without regard to the wiring. The placement location can be set freely. Further, since the facsimile procedure is not performed until the branch telephone is off-hook and the silent state or the CNG signal is detected, it is possible to cause the transmitting side to send an unpleasant facsimile signal sound when the incoming call is a call. There is no effect.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an embodiment in which the present invention is applied to a facsimile machine.

FIG. 2 is a flowchart of one embodiment of the operation of the facsimile machine of FIG. 1;

FIG. 3 is a flowchart of another embodiment of the operation of the facsimile machine of FIG. 1;

FIG. 4 is a block diagram of a specific example of a voltage monitoring unit.

FIG. 5 is a time chart illustrating an incoming call state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Line 2 Branch telephone 3 Facsimile connection terminal 4 Facsimile device 16 Voltage monitoring unit 26 Silence detection unit 27 CNG detection unit 31 Main control unit (CPU)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-142159 (JP, A) JP-A-4-242364 (JP, A) JP-A-63-82156 (JP, A) JP-A-4-142159 307845 (JP, A) JP-A-63-294048 (JP, A) JP-A-3-58561 (JP, A) JP-A-1-151654 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04M 11/00-11/10 H04M 1/00 H04M 1/72

Claims (1)

(57) [Claims] 1. A communication device connected to a telephone line by branching with a telephone, wherein the telephone is directly connected to a telephone line connected to the communication device, and off-hook detection means for detecting a hook state of the telephone. Identification signal detection means for detecting an identification signal, and silence detection means for detecting the continuation of a silence state, the identification signal detection means and the silence detection means when the off-hook detection means has detected the off-hook of the telephone A communication device branch-connected to a telephone line to a telephone line, wherein the communication device is operated.