JPH08289039A - Communication terminal equipment - Google Patents

Abstract

PURPOSE: To avoid mistake in on-hook/off-hook detection of a branch telephone set by discriminating a voltage change by a voltage detection circuit even under an environment such that a line voltage is changed slowly or unstability is caused due to the effect of noise. CONSTITUTION: In the communication terminal equipment in which a line voltage detection circuit 6 is connected in parallel with a telephone line 2 which a branch telephone set 3 is connected, a sampled line voltage V(n) and a line voltage V(n-T) sampled at a preceding fixed time T to the sampled time are sequentially compared for every sampling of the line voltage and a state change of the branch telephone set is discriminated when the result of discrimination that the voltage difference is larger than reference levels α, βreaches consecutively a prescribed number of times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device such as a facsimile device which can be used by connecting telephones in parallel to a telephone line.

[0002]

2. Description of the Related Art Recently, it has been widely used to connect telephones in parallel to a facsimile machine and use them as so-called branch telephones. However, in such a facsimile device, on-hook of the branch telephone,
Since the off-hook state cannot be detected, various problems occur when using an attached telephone or an external telephone.

FIG. 6 is a DC equivalent circuit diagram showing the connection state of the line voltage detection circuit according to this proposal. Each of the branch telephone 3, the auxiliary telephone 4, the external telephone 5, and the modem M of the facsimile apparatus F has an internal resistance as a load, and a telephone line having a predetermined specific resistance derived from the telephone exchange 1. At the end of 2, hook switch FS, C
The contacts are connected in parallel via the contact rs of the ML relay.

When the hook switch FS of the telephone set 3, 4, 5 is closed to go off-hook, or the contact rs of the CML relay of the facsimile apparatus F is closed to enter the incoming or holding state, the telephone line 2 is terminated. Since the combined resistance value generated in 1 is a value obtained by connecting the internal resistances of the telephone set off hook and the facsimile apparatus F in the on-hold state and the receiving state in parallel, if the number of units connected in parallel to the telephone line 2 increases. , Its combined resistance value decreases.

The line voltage detection circuit 6 is a hook switch F.
The shared voltage of the combined resistance formed at the end of the telephone line 2 is detected when S is closed or the contact rs of the CML relay is closed. For example, in a normal telephone line, DC48V is supplied from the telephone exchange 1. , The telephone line 2 has a one-way specific resistance of 500Ω to 2KΩ,
Branch telephone 3, accessory telephone 4 and external telephone 5
Have an internal resistance of 300Ω. The resistance value of the telephone line 2 varies depending on the installation locations of the telephones 3 to 5, but can be considered to be almost constant at the same installation location.

Therefore, under such a condition,
When the number of telephones connected to the telephone line 2 by off-hook (including a facsimile apparatus in an incoming state) increases, the combined resistance formed at the end becomes small and the fluctuation range thereof also becomes small. FIG. 7 shows the basic operation of the line voltage detection circuit 6, in which both the attached telephone 4 and the external telephone 5 connected to the telephone line 2 are in the on-hook state, and the facsimile apparatus F receives and holds the call. In the non-closed state that is not in, that is, in the standby state, the Vo level voltage (that is, the voltage corresponding to 48V) is detected.
When one of the telephones goes off-hook or the facsimile apparatus F receives a call, the DC circuit is closed and the level of the detected voltage drops to V1. The combined resistance of
As the number of off-hook telephones that exhibit the characteristic that the level of the detected voltage drops to V2, the voltage level difference that drops is gradually decreasing.

Conventionally, in order to detect the off-hook of the branch telephone, the facsimile device F stores the detection voltage levels V1 and V2 in advance and compares them with the voltage detected by the line voltage detection circuit 6. Since the line voltage varies depending on the country, region, and place of use, the detected voltage level V
1, it was necessary to adjust V2. Moreover, since the voltages were simply compared, they were easily affected by noise and the like.

[0008]

SUMMARY OF THE INVENTION The present invention has been developed in view of such circumstances, and a line voltage for detecting off-hook of a branch telephone even if the country or region where the communication terminal device is used is changed. You do n’t have to adjust the level,
An object of the present invention is to provide a communication terminal device using a method of discriminating a branch telephone with less malfunction even when it is susceptible to fluctuations due to noise and the like.

[0009]

The present invention, which is proposed to achieve the above object, is characterized by the following configurations. That is, the present invention proposed in claim 1
In the basic configuration in which the line voltage detection circuit is connected in parallel to the telephone line connected to the branch telephone, the sampled line voltage and the line voltage sampled a fixed time before the sampling time are compared for each sampling, The configuration is such that the on-hook and off-hook state changes of the branch telephone are first detected when the result of the determination that the difference is larger than the reference width reaches a predetermined number of times in succession.

Further, the invention proposed in claim 2 is such that the telephone line of the communication terminal device is closed, for example, the line holding state, an attached telephone, or an attached answering machine is connected to the telephone line. When you are in
The change in the on-hook and off-hook states of the branch telephone is detected by using the determination result obtained by executing the comparison / determination method mentioned in claim 1.

Further, the present invention proposed in claim 3 is characterized in that, when the line voltage sampled a predetermined time ago exceeds a predetermined reference level, the line voltage is replaced with a predetermined level for comparison.

[0012]

According to the communication terminal device of the present invention, each time the line voltage is sampled, it is compared with a preset reference level to judge the change in the state of the branch telephone. The sampled line voltage is sampled at a certain time before the sampling time and is compared successively with the line voltage fetched as previous data in the sampling memory. In the case of a gradual change with the passage of time (for example, the power is cut off and then gradually decreased), the change in the state of the branch telephone is not detected, so that no malfunction occurs.

Further, according to the present invention, the line voltage rises above and below the reference width under an unstable condition in which the line voltage fluctuates in a short period due to the influence of noise or the like. Even if the change over is repeated, the fluctuation range of the line voltage is continuously detected for a fixed time or longer, and the off-hook and on-hook detection of the branch telephone is not performed, so the reliability is high.

According to another aspect of the communication terminal device of the present invention, since the telephone line of the communication terminal device is closed, the line voltage level becomes low. Therefore, the voltage at the time of the state change of the branch telephone due to on-hook or off-hook is changed. When the variation difference becomes small, the comparison / discrimination method mentioned in claim 1 is executed, so that the state of the branch telephone can be discriminated without causing a malfunction in an environment where a malfunction easily occurs.

According to the communication terminal device of the third aspect,
In claim 1, when the line voltage sampled a predetermined time ago exceeds a predetermined reference level, the line voltage is replaced with a predetermined reference level for comparison. Therefore, while sampling the required number of line voltages, the branch phone goes off-hook and immediately returns to the on-hook state, or vice versa, on-hook and immediately returns to the off-hook state. In any case, the data stored during the sampling period is compared as the previous data held at a predetermined reference level (at least a level at which on-hook / off-hook can be clearly judged from this level), and therefore At the time of sampling, the state change is reflected and the state change of the branch telephone can be detected without error.

FIG. 5B shows a rapid change in the off-hook state and on-hook state of the branch telephone set solved by the third aspect. FIG. 5B shows the branch telephone set from the on-hook state to the off-hook state. It shows the state of changing to.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a diagram showing an example of the internal configuration of the facsimile apparatus F which is an embodiment of the present invention. In this facsimile apparatus F, branch telephones 3 are connected in parallel to the same telephone line 2, and in the main body of the facsimile apparatus F, a built-in accessory telephone 4 and an external telephone 5 connected to a telephone terminal are provided with switching means. It is connected in parallel to the telephone line 2 through the constituent H and L relays. Although not shown, a built-in answering machine may be connected instead of the external telephone 5, or a built-in answering machine may be newly added.

In the main body of the facsimile device F,
A line voltage detection circuit 6 is connected in parallel to the telephone line 2, and a polarity reversing circuit 7 is connected to the telephone line 2 via a contact rs of a CML relay. One attached telephone 4,
The external telephone 5 is switched and connected to the telephone line side and the extension circuit side via H relays and L relays which are control switching relays having switching contacts a and b which are switching-controlled by the CPU 11. On the extension circuit side, the extension power supply circuit 8 and the pseudo bell generation circuit 9 that outputs a ringing tone for an extension call are switched by extension switching relays T1 and T2 having switching contacts a and b. In addition, hook detection circuits OH1 and OH2 for detecting the off-hook and on-hook of the handset and the ringing signal (16 Hz) from the outside line are respectively detected in the attached telephone 4 and the external telephone 5. The ringing signal detection circuit 10 is connected.

Here, each of the hook detection circuits OH1 and OH2 has a photo coupler, the facsimile apparatus F is in a standby state, and each of the telephones 4 and 5 is connected to the telephone line 2 by the H and L relays. While the handset is off, the handset of each of the telephones 4 and 5 is detached, the respective hook switches FS and FS are closed, and when it goes off-hook, the off-hook is detected by the loop current flowing from the telephone line 2 to the photocoupler, and the transmission When the handset is placed, the hook switches FS and FS are opened, and the loop current does not flow when it goes on-hook, the on-hook is detected, and the detection signal is input to the CPU 11 and is judged here. In the present embodiment, the hook detection circuit is configured by the photocoupler, but the hook detection circuit can be configured by a hook switch having a contact for hook detection. In this case, since there is no influence of the line voltage and current, the off-hook of the telephones 4 and 5 can be detected more accurately.

Me is the sampling data of the line voltage taken in as the previous data, and the first and second reference widths α necessary for judging the on-hook and off-hook states of the branch telephone when the line is closed or not closed. , Β, etc. are stored in the internal memory. Therefore, a part of this is used as a sampling memory to store the line voltages sampled from T time ago to immediately before and sequentially updatable. As the sampling memory, a shift register can be used as it is, which stores the data T hours before the sampled current data and sequentially erases the oldest data of the latest data.

In addition, the CPU 11 causes the call signal detection circuit 10 to call the call signal C of 16 Hz when calling from an outside line.
When I is detected, the contact rs of the CML relay is closed, the modem M is connected to the telephone line 2, and when the facsimile apparatus F receives the call and is in the hold state, the contact rs of the CML relay is held in the closed state. . Furthermore, if the answering machine is set to the answering machine mode, the automatic answering function of the built-in answering machine enables an automatic incoming call. C1 is a capacitor,
C1 is connected in parallel to the contact rs of the CML relay, and even if the contact rs of the CML relay is open, the modem M is connected to the telephone line 2 for AC signals.

An extension call can be made between the attached telephone 4 and the external telephone 5. Therefore, either one, for example, the telephone 4
When the other party's extension number is designated by turning off the hook and operating the ten-key pad, the CPU 11 closes the contact a of the L relay and further closes the contact a of the extension switching relay T2 to operate the pseudo bell generating circuit 9. Then, the other party's telephone 5 is called. On the other hand, when the called telephone 5 of the other party goes off-hook, the CPU 11 keeps the contact a of the L relay closed and the contact b of the extension switching relay T2 closed to connect the extension power supply circuit 8. Make a call.
At this time, the contact a of the H relay is closed and the extension switching relay T
1 is such that the contact b is closed.

Steps 100 to 107 of FIG. 1 are flowcharts showing the basic operation of the present invention.
It is executed every m seconds. In the present invention, the sampled line voltage Vn is fetched, the presence or absence of the status change of the BRC port described later is discriminated, and if the status is changed, the timer is set. Here, the set value of the timer is a value obtained by adding the sampling period td to the line voltage take-in prohibition period ta. The former line voltage take-in prohibition period ta is a waiting time until the line voltage stabilizes, and the latter sampling period td is a period for sampling the number of line voltages necessary for judging whether the branch telephone is on-hook or off-hook. Is.

If the status has not changed, the remaining time of the timer is referred to. If the remaining time of the timer is 0, the storage of the sampling data has already been completed, and the reference voltage updating routine and the status setting routine, which will be described later, are executed. When the remaining time of the timer is less than Td,
Since the storage of the sampling data is not completed, the reference voltage update routine is executed to store the sampling data. If the remaining time Td of the timer is longer than the waiting time until the line voltage stabilizes, the process is terminated.

Steps 200 to 210 of FIG. 2 show the basic operation of the reference voltage update routine, particularly the basic operation in the off-hook status. Each time the line voltage is sampled and taken in, the line voltage is compared with the line voltage V (n−T) before the fixed time T from the sampling time at that time. This line voltage V (n-T) is the line voltage V
The line voltage is sampled T time earlier than (n) and is stored in the sampling data memory.

Actually, as a pre-process for this comparison / determination,
Line voltage V (n-T) sampled before T time
Has exceeded a predetermined reference level Vr (see FIG. 5) for determining the off-hook of the branch telephone, and if it exceeds the predetermined reference level Vr, the sampled line voltage V (n) And the difference between the predetermined reference level Vr and the first and second change widths α and β are determined, and if the difference exceeds these change widths, the port counter is incremented and otherwise. In some cases decrement.

In this comparison judgment, the OH detection circuit OH1,
Based on the detection result of OH2, the first reference width α is set when the line voltage is in the non-closed state (standby level), and the second change width β is set when the line voltage is in the closed state. It is adopted as a reference for comparison of the sampled line voltage V (n). In this way, the count value of the port counter is changed each time the line voltage V (n) is taken in. If the count value exceeds a preset predetermined value (“2” in the example in the figure). , Set the status of the BRC port to ON.

On the other hand, when the line voltage V (n-T) sampled before T time does not exceed the predetermined reference level Vr, the sampled line voltage V (n) is obtained.
And the line voltage V (n-
It is determined whether or not the difference from T) exceeds the first and second change widths α and β, and if it exceeds, the port counter is incremented, and if not, decremented.

The port counter has an initial value of "0" and is incremented in accordance with the above-mentioned comparison / determination result.
If decremented and the count value becomes larger than "2", B
The status of the RC port is turned on and the count value is cleared to 2. However, if the count value becomes smaller than "0", the status of the BRC port is turned off and the count value is cleared to "0". In this embodiment, the count value of the port counter and 0, 2
Although it is compared with, the appropriate value should be taken regardless of this value.

Steps 300 to 308 of FIG. 3 are flowcharts of a status setting routine for discriminating between on-hook and off-hook of the branch telephone based on the ON / OFF status of the BRC port status set by the basic operation of FIG. Shows. For on-hook and off-hook of the branch telephone, after the count value of the port counter reaches a predetermined value, the OH counter (down counter) of the BRC is further subtracted, and when the count value reaches 0, the status flag is turned on, It is determined by updating to OFF. The BRC OH counter is set to an initial value such as 40 (corresponding to 400 milliseconds).

[0031]

According to the communication terminal device of the present invention as set forth in claims 1 and 2, the branch telephone is on-hook only when the state in which the voltage level changes continues for a predetermined time in a short time. Since the off-hook state is determined, the state change is not detected even if the voltage level changes greatly in a short time. Therefore, even when the line voltage is unstable due to the influence of noise or the like, the branch telephone can be discriminated without error by the line voltage detection circuit.

Particularly, in the communication terminal device of the present invention as defined in claim 2, the difference in line voltage fluctuation when the state of the on-hook or off-hook state of the branch telephone is changed becomes smaller than that when the line is opened. When closed, the line telephone can be correctly identified by the line voltage detection circuit. Further, according to the communication terminal device of the present invention described in claim 3, the branch voltage is sampled while the line voltage is being sampled for the status judgment of the branch telephone by the comparison judgment method described in claim 1. Even when the telephone is turned off and instantly returns to the on-hook state, the state change can be performed without error.

[Brief description of drawings]

FIG. 1 is a flowchart showing a basic operation of the present invention for taking a line voltage and making a comparison / determination.

FIG. 2 is a flowchart showing a basic operation of a reference voltage updating routine.

FIG. 3 is a flowchart showing a basic operation of a BRC port status setting routine.

FIG. 4 is a block diagram showing a basic configuration of a facsimile apparatus which is an embodiment of the present invention.

FIG. 5 is a time chart showing a change in line voltage when the branch telephone changes state to on-hook and off-hook.

FIG. 6 is a basic configuration diagram of a DC equivalent circuit including a branch telephone and a line voltage detection circuit.

FIG. 7 is a time chart showing the basic operation of the line voltage detection circuit.

[Explanation of symbols]

F ... Facsimile device (communication terminal device) 1 ... Telephone switch 2 ... Telephone line 3 ... Branch telephone 4 ... Auxiliary telephone 5 ... External telephone 6 ... Line voltage detection circuit 11 ... CPU V (n) ... Line voltage sampled V (n-T) ... Line voltage sampled before T time

Claims (3)

[Claims] 1. A communication terminal device in which a line voltage detection circuit is connected in parallel to a telephone line connected to a branch telephone,
Each time the line voltage is sampled, the line voltage sampled and the line voltage sampled a fixed time before the sampling time are sequentially compared, and the difference is greater than the predetermined reference width. A communication terminal device adapted to determine a change in the state of a branch telephone when the number of times is reached. 2. The communication terminal device according to claim 1, wherein when the telephone line of the communication terminal device is in a closed state, a sampled value of the line voltage and a line sampled before a fixed time. A communication terminal device for discriminating a state change of a branch telephone based on a discrimination result obtained by sequentially comparing with a voltage. 3. The communication terminal device according to claim 1, wherein when the line voltage sampled a predetermined time ago exceeds a predetermined reference level, the line voltage is replaced with a predetermined level for comparison. Terminal device.