JPS62231555A - Telephone line switching device - Google Patents

Abstract

PURPOSE:To use any telephone sets by connecting all the telephone sets to an off-hook detection circuit when the operation is on standby without incoming and outgoing calls and switching the operation so that at least one telephone set is connected to a telephone line when an incoming call detection signal is received. CONSTITUTION:Normally changeover switches 22, 23, 28 and 29 in switch means 9 and 10 are thrown to the side of the off-hook detection circuits 7 and 8. when an incoming call is present, an incoming call detection circuit 3 detects said call, and the changeover switches 22, 23, 28 and 29 in the switch means 9 and 10 are thrown to the side of the telephone lines 1 and 2. When a telephone set (n) is hooked off, a switch means l is thrown to the side of the telephone lines 1 and 2. By dialing the telephone set (n) the operation attains a calling state. When the telephone set (n) is hooked on, it returns to its original standby state. With this simple constitution, one system telephone line can be switched and used between plural telephone sets.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a telephone line switching device for switching a plurality of telephones connected to one telephone line.

[Prior art]

Conventionally, for devices that switch telephone lines between multiple telephones, there is a PB that switches between multiple telephone lines and multiple extensions.
There are button telephone devices and home telephones that use X or one or two telephone lines with several telephones.

However, the conventional PBX described above has a very complicated structure. Further, key telephone devices, home telephones, etc. require dedicated telephones, and have drawbacks such as incompatibility of telephones.

[Object of the Invention] The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a telephone line switching device that can use any telephone and has a simple structure. It is.

[Structure of the invention]

In order to achieve the above object, the telephone line switching device of the present invention detects the presence or absence of a signal delivered through the telephone line in a telephone line switching device that switches a plurality of telephones connected to one telephone line. An incoming call detection circuit that issues an incoming call detection signal, an on-hook detection circuit during a call that detects on-hook operation of the handset during a call, and outputs an on-off/disconnect detection signal, and an off-hook detection circuit that detects the off-hook state when the handset is removed. an off-hook detection circuit that emits a signal; a switching device that switches the connection of the telephone between the off-hook detection circuit and the telephone line; and control that controls the switching direction of the switching device in accordance with the outputs of the incoming call detection circuit and the off-hook detection circuit. and the above control unit,
The switching means is driven so that all the telephones are connected to the off-hook detection circuit when there is no incoming call and no oscillation, and at least one telephone is connected to the telephone line when the above-mentioned incoming call detection signal is received. The switching means is driven so that when the off-hook detection signal is received, a telephone other than the off-hook telephone is connected to the off-hook detection circuit, and when the on-hook detection signal is received, the telephone is connected to the off-hook detection circuit. The switching means is set to be driven so that the telephone is connected to the off-hook detection circuit, so that the telephone can be easily switched.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 5.

As shown in FIG. 1, the telephone line switching device according to the present invention includes an incoming call detection circuit 3 connected to telephone lines 1 and 2 of
, an on-hook detection circuit 4 during a call, an off-hook detection circuit 7 corresponding to the telephone 5, an off-hook detection circuit 8 corresponding to the telephone 6, a switching means 9 for switching the telephone 5 between the off-hook detection circuit 7 and the telephone diagrams vA1 and 2, and a telephone. 6 between the off-hook detection circuit 7 and the telephone lines 1 and 2, and a control section that controls the switching direction of the switching means 9 and 10 by the output of the incoming call detection circuit 3 and the off-hook detection circuit 7. Consists of 11.

The incoming call detection circuit 3 detects the presence or absence of a signal transmitted through the telephone lines 1 and 2 and issues an incoming call detection signal, and includes a resistor 12 and a capacitor 13, which are connected to the telephone lines 1 and 2, respectively. A diode bridge 14, a photodiode 15 and a Zener diode 16 connected in series on the output side of the diode bridge 14, a phototransistor 17 that constitutes a photocoupler 18 together with the Zener diode 16, and a power supply circuit (Vcc). It is composed of a resistor 19 provided between them. This incoming call detection circuit 3 may have a configuration other than the circuit described above as long as it can detect incoming calls. The on-hook detection circuit 4 during a call is
It detects the on-hook operation of the handset during a call and outputs the on-hook detection signal 18, and is composed of a resistor 20 connected in series and a switch 21 consisting of a relay that is turned on by the on-hook operation of placing the handset during a call. It is connected in parallel with the capacitor 13 mentioned above. The switching means 9 usually consists of a relay, and the switching direction is controlled by a control section 11. It has interlocking changeover switches 22 and 23, and each movable contact 22a and
23a are connected to the telephone set 5 through power supply lines 33 and 34, respectively.

A fixed contact 22b of the changeover switch 22 is connected to a power supply line 24 connected to the telephone line 1, and a fixed contact 22C is connected to a positive input terminal of a comparator of the off-off detection circuit 7 via a power supply line 35.

On the other hand, the fixed contact 23b of the changeover switch 23 is connected to the telephone line 2.
The fixed contact 23c is connected to the power supply line 25 connected to the off-hook detection circuit 7, and the fixed contact 23c is grounded through the resistor 27 of the off-hook detection circuit 7. The off-hook detection circuit 7 detects an off-hook state in which the handset is removed and generates an off-hook signal, and includes a comparator 26, a resistor 27, and a resistor 39 provided between the power supply circuit and the positive input terminal of the comparator 26.
The output of the comparator 26 is +f[, and the output of the comparator 26 is
has been entered. The comparator 26 is connected to the power supply path 3 mentioned above.
5 and the voltage of the power supply line 36 connected to the negative input terminal. The power supply line 36 is connected to a comparison voltage source that is lower than Vcc and higher than the potential of the power supply line 35 when the telephone 5 is off-hook and current flows, causing a voltage drop.

The comparator 26 outputs a low level output when the telephone 5 is on-hook, that is, when the potential of the power supply line 35 is higher than the potential of the power supply line 36, and conversely, when the telephone 5 is off-hook, that is, the potential of the power supply line 35 is higher than the potential of the power supply line 36. When the potential is lower than the potential of line 36, an off-hook signal, which is a high level output, is sent. Further, the configuration and connection relationship of the telephone a6, the switching means 10, and the off-hook detection circuit 8 are the same as those of the telephone 5, the switching means 9, and the off-hook detection circuit 7. The switching means 10 includes a changeover switch 28 having a movable contact 28a and fixed contacts 28b and 28C,
A changeover switch 29 having a movable contact 29a and fixed contacts 29b and 29c is provided, and the movable contacts 28a and 2
9a are connected to the telephone 6 through power supply lines 37 and 38, respectively.

Further, the off-hook detection circuit 8 is provided with a comparator 30 and resistors 31 and 32.

In the above configuration, the operation of this telephone line switching device is (1)
) On standby, (2) when receiving a call, (3) when making a call, and (4) when making a call.

(1) During standby, as shown in FIG.
The movable contacts 22a, 23a, 28a, and 29a of the changeover switches 22, 23, 28, and 29 at 0 are pushed toward the fixed contacts 22C, 23c, 28C, and 29C, respectively. Therefore, only the incoming call detection circuit 3 is connected to the telephone line l.2. In addition, in the event of a power outage, the control unit 11 controls the switching means 9 and 1.
In the changeover switches 22, 23, 28, and 29, each of the movable contacts 22a, 23a, 28a, and 29a is connected to the fixed contact 22, respectively.
b, 23b, 28b, and 29b, the connection is reversed from that shown in FIG. 1, and two telephones 5 and 6 are connected to telephone lines 1 and 2. Therefore, the telephones 1 and 2 can be used even during a power outage.

(2) When an incoming call is received, the incoming signal is transmitted to the incoming call detection circuit 3 through the telephone lines 1 and 2, and the resistor 12 and capacitor 1
3. Diode bridge 14, Zener diode 16
A current flows through the photocoupler 18, and the output level of the photocoupler 18 changes. This change in output level is input to the control unit 11 as an incoming call detection signal to notify the controller 11 of the incoming call. Then, the control unit 11 causes all of the changeover switches 22, 23, 28, and 29 of the changeover means 9 and 10 to be set to the telephone 5.
6 side, that is, each movable contact 22a, 23a, 28
a and 29a are fixed contacts 22b, 23b, and 28b, respectively.
- Switched to 29b or switching means 9 and 10
Either one of the telephones 5 and 6 is connected to the telephone line 1 and 2 by switching only one of them. Here, the control unit 11 confirms the incoming call.

When the call is received, the receiver may generate a ringtone or display some kind of incoming call display. Furthermore, both or only one of the switching means 9 and 10 may be switched to ring both the telephones 5 and 6, or only one of them. Furthermore, a configuration may be adopted in which the user can specify in advance, using a key or the like, where to play a ringtone or display an incoming call when an incoming call is received.

(3) For example, when making a call using the telephone 5, the telephone 5 is equipped with resistors 27 and 39 as shown in FIG.
A voltage Vcc is applied via. In the on-hook state in which the receiver is placed, the power supply lines 33 and 34 are open, so no current flows, and the voltage of the power supply line 35 is approximately Vcc. Therefore, the potential of the power supply line 35 is higher than the potential of the power supply line 36, and the output of the comparator 26 is at a low level. Now, pick up the handset to make a call,
In the off-hook state, the power supply lines 33 and 34 are short-circuited with low resistance (300Ω or less) in the telephone 5, current flows through the power supply line 33, and the potential of the power supply line 35 drops. Therefore, the potential of the power supply line 35 becomes lower than the potential of the power supply line 36, and the output of the comparator 26 changes to a signal at the l, ow level, or an off-hook detection signal at the high level. The control unit 11 detects this change in the output of the comparator 26 and switches the changeover switches 22 and 23 of the changeover means 9 to the telephone lines 1 and 2 side. Thereby, the telephone set 5 is connected to the telephone lines 1 and 2, and by dialing the telephone set 5, it becomes possible to make a call.

(4) When the telephone 5 is on a call, the telephone 5 is off-hook, so the switch 21 of the on-hook detection circuit 4 is open during a call, and the changeover switch 2 of the switching means IO is opened.
Day 29 is pushed to the off-hook detection circuit 8 side. Then, only the changeover switches 22 and 23 of the changeover means 9 are switched to the telephone lines 1 and 2 side. Here, if the telephone 6 goes off-hook, the off-hook detection circuit 8 outputs an off-hook detection signal to the control section 11 in the same way as in (3) when making a call, but the control section 11 indicates that the telephone 5 is already on the line. Since we know that, the signal switching unit 1
The changeover switches 28 and 29 of 0 cannot be switched to the telephone lines 1 and 2 side. Therefore, no matter how much the telephone 6 is operated, the telephone 6 cannot be used, and the telephone 5 during a call is not affected in any way.

Next, when the telephone 5 finishes the call and goes on-hook, the telephone lines 1 and 2, which had been shorted through the low resistance (300Ω or less) of the telephone 5, become almost open, and the resulting voltage change detects an incoming call. It is detected by the circuit 3 and outputted to the control section 11 as an on-hook detection signal. The voltage change detection process in the incoming call detection circuit 3 is performed as follows.

Voltage VA between point A of telephone line 1 and point B of telephone line 2
As shown in FIG. 2(a), II is ■ during a call, and ■ when the receiver is on-hook.

become. Due to the voltage change 40 at this time, in the first day of the photocoupler, a current 41 shown in the figure (d) flows, and the voltage VC at the zero point on the output side becomes a pulse voltage 42 as shown in the figure (b). By receiving this pulse voltage 42, the control unit 11 turns on 43 the switch 21 of the on-hook detection circuit 4 during a call, as shown in FIG.
Check the status of. If the voltage (2) of the telephone lines 1 and 2 is vo, the current 44 flows through the photocoupler 18 through the resistor 2o by turning on the switch 21, and the voltage (2) becomes a pulse voltage 45. If VAI is ■. Otherwise, almost no current will flow through the photocoupler 18, and the voltage will be ■. No pulse appears. The resistance values of the resistors 12 and 20 and the Zener diode 16 are selected in advance to perform such an operation.

For example, the Zener diode 16 has a Zener voltage VZ
D satisfies V+<Vzo<Vo.

As described above, the pulse voltage 45 of the voltage ■c is applied to the control unit 1.
1, the control unit 11 determines that the telephone 5 that was in the middle of a call is on-hook (end of the call), and the changeover switches 22 and 23 of the switching means 9 switch the off-hook detection circuit from the telephone line 1 and 2 side. 3 side, and returns to the standby state shown in FIG.

By the way, as shown in FIG. 2(b), the pulse voltage 42
The reason why the switch 21 of the on-hook detection circuit 4 is turned on during a call to check the telephone lines 1 and 2 after this is to distinguish dial pulses when the telephone 5 dials. During dialing, a dial pulse 46 shown as a voltage VA8 in FIG. 3(a) is sent to the telephone line 1.2, and a current 47 flows through the photocoupler 18, causing the output voltage of the incoming call detection circuit 3 to increase. becomes a pulse voltage 48. By receiving this pulse voltage 48, the control unit 11 turns on 49 the switch 21 of the on-hook detection circuit 4 during a call, and checks the state of the telephone line 1.2, as in the case of FIG. 2 described above. However, at this time, the voltage VA of telephone lines 1 and 2
Since II is V+ (<Vzo), no current flows through the photocoupler 18 and no pulse appears on the voltage ■c.

Therefore, the control unit 11 knows that the telephone line 1.2 remains closed, and distinguishes this from the end of the call.

The operation of this device is shown in a flowchart as shown in FIG.

First, normally, the Fl is in standby state, and the switching means 9.1
0 changeover switches 22, 23, 28, and 29 are turned to the off-hook detection circuits 7 and 8 side, respectively. If there is an incoming call in this state, this is detected by the incoming call detection circuit 3, and F2
At the switching means 9, the changeover switch 22, 23, 28 of lO
・29 is knocked down to the telephone line 1 and 2 side. As described above, as a method for this switching, any one of the switching means 9 and 10 may be switched, or only the display on the switching means 9 and IO may be used. An example of how to switch is given. At F2, the telephone lines 1 and 2 are directly connected in parallel to the two telephones 5 and 6, so both telephones 5 and 6 ring in response to an incoming call (F3). If there is no incoming call, the control section 11 learns of this through the incoming call detection circuit 3 and returns the switching means 9 and 10 to the Fl standby state.

When one of telephones n of telephones 5 and 6 goes off-hook at F4, it is detected by the control unit 11 through the corresponding off-hook detection circuit n, and the switching means m on the Jam side of the other telephone that did not go off-hook is waited for. The state is returned to the off-hook detection circuit m side (F5).

If you put phone n on hook while talking on F6 (F7)
, this is detected and the signal switching section n is returned to the standby state of Fl (F8).

On the other hand, when making a call, if telephone n goes off-hook (F
9), the switching means n is tilted to the telephone port vA1/2 side (F
IO). When dialing telephone n using Fil, the state shifts to F6, which is in the middle of a call. When the outgoing call is interrupted with FIO/Fil (telephone $1n goes off-hook), the state shifts to F8 and returns to the original standby state (Fl).

In this embodiment, a configuration in which two telephones 5 and 6 are arranged has been described, but by providing as many pairs of switching means 9 and off-hook detection circuits 7 and 8 as the number of telephones to be arranged, three Needless to say, switching between more than one telephone set can be performed in the same manner.

Further, it is also possible to connect not only the telephones 5 and 6 but also various telephone terminals such as a modem and a facsimile to the switching means 9 and 10.

Furthermore, as an application example of the present invention, it is also possible to configure a data communication terminal device as shown in FIG. In this device, the incoming call detection circuit 3, the on-hook detection circuit 4 during a call, the off-hook detection circuit 7, and the switching means 9 are the same circuits as those shown in FIG. 1. And switch 5
A modem 51 is connected to the telephone lines 1 and 2 via 0, and a terminal device 52 is connected to this modem 51. In this device, the operating state of the telephone 5 can be completely known by the control unit 53, so
This enables detailed services.

〔Effect of the invention〕

As described above, the telephone line switching device of the present invention is a telephone line switching device that switches a plurality of telephones connected to one telephone line, and detects the presence or absence of a signal delivered through the telephone line, and sends an incoming call detection signal. an incoming call detection circuit that emits;
The on-hook detection circuit during a call detects on-hook operation of the handset during a call and outputs an on-hook detection signal, the off-hook detection circuit detects the off-hook state when the handset is removed and outputs an off-hook detection signal, and the connection of the telephone is described above. The apparatus includes a switching means for switching between the off-hook detection circuit and the telephone line, and a control section for controlling the switching direction of the switching means in accordance with the outputs of the incoming call detection circuit and the off-hook detection circuit. The control section drives the switching means so that all the telephones are connected to the off-hook detection circuit when there is no incoming call or oscillation, and when the above-mentioned incoming call detection signal is received, the switching means is activated so that all the telephones are connected to the off-hook detection circuit. The switching means is driven so that the telephone is connected to the telephone line, and when the off-hook detection signal is received, the switching means is driven so that a telephone other than the off-hook telephone is connected to the off-hook detection circuit. The configuration is such that when receiving an on-hook detection signal, the switching means is driven so that the telephone is connected to the off-hook detection circuit. You can switch between multiple phones and use any phone without the need for a special phone.Thus, the phone user can use it just as if they were using a single phone. This has the effect of allowing you to use multiple telephones with a simple operation.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 3 is a timing chart of the detection timing in the on-hook detection circuit 4 during a call shown in FIG. FIG. 5 is a block diagram showing an example of application of the present invention. 1 and 2 are telephone lines, 3 is an incoming call detection circuit, 4 is an on-hook detection circuit during a call, 5 and 6 are telephones, 7 and 8 are off-hook detection circuits, 9 and IO are switching means, and 11 is a control section. Patent applicant Sharp Corporation) Mi; Figure $2 Figure $3 ■0 Figure 4 Figure 5

Claims (1)

[Claims] 1. A telephone line switching device that switches multiple telephones connected to one telephone line includes an incoming call detection circuit that detects the presence or absence of a signal transmitted through the telephone line and issues an incoming call detection signal, and an on-hook receiver during a call. An on-hook detection circuit during a call that detects motion and outputs an on-hook detection signal; an off-hook detection circuit that detects the off-hook state when the handset is removed and issues an off-hook detection signal; and a telephone connection between the off-hook detection circuit and the telephone line. and a control unit that controls the switching direction of the switching unit in accordance with the outputs of the incoming call detection circuit and the off-hook detection circuit, and the control unit is configured to switch the switching direction when there is no incoming call or oscillation. driving the switching means so that the telephone sets are connected to the off-hook detection circuit, and when receiving the incoming call detection signal, driving the switching means so that at least one telephone set is connected to the telephone line;
When receiving the above-mentioned off-hook detection signal, the switching means is driven so that a telephone other than the off-hook telephone is connected to the off-hook detection circuit, and when the above-mentioned on-hook detection signal is received, the telephone is connected to the off-hook detection circuit. 1. A telephone line switching device, characterized in that said telephone line switching device is configured to drive a switching means so as to