JPH0736576B2 - Phone system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a telephone system in which a call position is freely selectable by connecting a plug of a telephone to one of a plurality of telephone outlets.

2. Description of the Related Art Conventionally, as shown in FIG. 4, this type of telephone system has been designed so that a call position can be freely selected by connecting a plug 3 of a telephone 2 to one of a plurality of telephone outlets 1. Was there. In addition to the telephone lines L ₁ and L ₂ to which the telephone 2 is plugged, standby lines L ₃ and L ₄ are pre-wiring (four-line pre-wiring) in each telephone outlet 1, but FIG. The protection lines L ₃ and L ₄ are not used in. By the way, in such a conventional example, there is a problem that the telephone call position cannot be changed by changing the telephone outlet 1 to which the telephone 2 is connected during a telephone call. That is, during a call, if the plug 3 of the telephone 2 is pulled out from one of the telephone outlets 1 and is inserted into the other telephone outlet 1 to change the call position, the telephone line is disconnected when the plug 3 is pulled out of the one telephone outlet 1. Since L ₁ and L ₂ are released, a telephone exchange (not shown) determines that the call ends when the telephone lines L ₁ and L ₂ are opened. Therefore, the telephone 2 moves during the call. There was a problem that I could not do it.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to provide a telephone system capable of easily moving a telephone even during a call.

DISCLOSURE OF THE INVENTION (Embodiment 1) FIG. 1 shows an embodiment of the present invention. Telephone lines L ₁ and L ₂
In the same telephone system as the conventional example in which the call position can be freely selected by connecting the plug 3 of the telephone 2 to any of the plurality of telephone outlets 1 in which the protection lines L ₃ and L ₄ are wired, the protection line L _3, L ₄ are wired into the outlet 1 and the control circuit, the impedance elements 4 connected to the control line L _3, L ₄ provided in attachment plug 3, the telephone line L _1, L ₂ A voltage change detecting means 6 for detecting the rise of the line voltage, an attachment / detachment detecting means 7 for detecting attachment / detachment of the telephone 2 depending on whether or not the impedance element 4 is connected between the control lines L ₃ and L ₄ , and a voltage change detecting means. 6 If set to hold by shorting the telephone line L _1, L ₂ by resistance R ₀ when the removal detection signal of the telephone is obtained from the rise detection signal is obtained and detachment detecting means 7 It is provided with a hold control circuit 9 composed of more the holding means 8 to reset the hold state when the connection detection signal of the telephone set 2 from the detachment detection means 7 was obtained also. Here, detachment detection unit 7 detects a control line L _3, the impedance elements 7a which is connected in parallel to L ₄ in series circuit between the DC power source 7b, the rise of the voltage change between the control line L _3, L ₄ It is composed of a rising edge detection circuit 7c and a falling edge detection circuit 7d that detects the falling edge of the voltage change. When the voltage between the control lines L ₃ and L ₄ rises, the plug 3 is pulled out from the telephone outlet 1. Detachment detection signal (“H” level) when it is determined that the telephone 2 is removed
And the voltage between the control lines L ₃ and L ₄ falls, it is determined that the plug 2 is plugged into the voltage outlet 1 and the telephone 2 is connected, and a connection detection signal (“H” level) Is output. Also,
The holding means 8 includes an AND circuit 8a to which the output of the voltage change detection means 6 and the output of the rising detection circuit 7c of the attachment / detachment detection means 7 are input, an RS latch circuit 8b, and an RS latch circuit.
An AND circuit 8c to which the output of 8b and the fall detection circuit 7d is input, a delay circuit 8d that delays the output of the AND circuit 8c to form a reset signal for the RS latch circuit 8b, and both AND circuits 8a and 8c are respectively provided. It is formed with a contact control circuit 8e which is inputted as a set signal and a reset signal and controls the contact S _{0. When the} output of the AND circuit 8a becomes "H" level, the contact S ₀ is turned on and the resistance R ₀ is transferred to the telephone. It is connected to the lines L ₁ and L ₂ and set to the hold state, and when the output of the AND circuit 8c becomes the “H” level, the contact S ₀ is turned off and the hold state is reset.

The operation of the embodiment will be specifically described below with reference to FIG. In addition, FIG. 3 (a) shows the voltage V between the telephone lines L ₁ and L _2.
12 and FIG. 3 (b) are time charts showing changes in the voltage V ₃₄ between the control lines L ₃ and L ₄ . Now, when the plug 3 of the telephone set 2 is connected to any of the telephone outlets 1, the change of the voltages V ₁₂ and V ₃₄ in the normal non-talking state T ₁ , the receiving state T ₂ and the talking state T ₃ is the first. Figure 3 (a)
The voltage waveform is as shown in the left half of (b), the hold control circuit 9 does not operate (contact S ₀ remains in the off state),
A normal call is made regardless of the hold control circuit 9. It should be noted that t ₁ is the time when the call arrives and t ₂ is the time when the call starts. here,
Need to change occur talking position during a call, t ₃ when pulling out the attachment plug 3 of the telephone set 2 from the telephone outlet 1 at the time, the control line L _3, the L impedance element 4 which is connected to ₄ is removed Becomes the control line
The voltage V ₃₄ of L ₃ and L ₄ rises from the divided voltage E ′ by the impedance elements 4 and 7a of the DC power supply voltage E to the DC power supply voltage E, and the telephone line L ₁ and L ₂ are removed because the telephone 2 is removed. The voltage V ₁₂ between them also rises. The rising edge of the voltage V ₃₄ is detected by the rising edge detection circuit 7c of the attachment / detachment detection means 7, and the attachment / detachment detection means 7 outputs a removal detection signal (“H” level). On the other hand, the rising edge of the voltage V ₁₂ is detected by the voltage change detecting means 6, and the rising edge detection signal (“H” level) is output from the voltage change detecting means 6. When the removal detection signal and the rising detection signal are simultaneously output in this way, the output of the AND circuit 8a of the holding means 8 becomes "H" level, the set signal is input to the contact control circuit 8e, and the contact S ₀ Is turned on and the resistance R ₀ is on the telephone line
It is connected to L ₁ and L ₂ and the hold state T ₇ starts. Then t ₄
At this point, when the plug 3 of the telephone 2 is reconnected to another telephone outlet 1, the telephone 2 is reconnected to the telephone line 2 so that the call can be continued.
At this time, at the same time, the impedance element 4 is again connected between the control lines L ₃ and L ₄ , and the voltage V ₃₄ drops, and the output of the fall detection circuit 7d of the attachment / detachment detection means 7 becomes "H". It becomes the level and the connection detection signal is output. An AND circuit in which this connection detection signal is input to one input end
Since the other input end of 8c is the output of the RS latch circuit 8b (“H” level), the output of the AND circuit 8c becomes “H” level by the input of the connection detection signal and the reset signal is Is output. This reset signal is the contact control circuit 8e
The contact S _{0 is} turned off by inputting to, and the hold state is reset. The reset signal is delayed by the delay circuit 8d, and the RS latch circuit is used.
8b is reset and ready for the next pending condition. Also, at the time t ₅ when the hold state T ₇ is reset, the resistor R ₀ is disconnected and the voltage V ₁₂ rises, and at the time t ₆ when the call ends and the handset is dropped, the voltage V ₁₂ further rises. the rising time of the voltage, the voltage V ₃₄ does not change, without removal detection signal is output from the removable detecting section 7, the aND circuit 8a output remains "L" level, t _5, t _{At the 6th} time point, the holding means 8 of the holding control circuit 9 does not malfunction. Also, in the no-call state T ₆ , the telephone 2
When the plug plug 3 of is pulled out from the telephone outlet 1, the voltage V ₃₄ rises at the time point t ₇ of pulling out, and the removal detection signal is output from the attachment / detachment detection means 7, but the telephone lines L ₁ and L _Since the voltage V ₁₂ between ₂ does not change, the rising detection signal is not output from the voltage change detection means 6, and the holding means 8 of the holding control circuit 9 does not malfunction at time t ₇ .

[Advantages of the Invention] As described above, the present invention provides a telephone system in which a call position can be freely selected by connecting a plug of a telephone to any of a plurality of telephone outlets in which telephone lines are wired. In addition to wiring the control line to the control line, an impedance element connected to the control line is provided in the plug, and whether the impedance change element is connected between the control line and the voltage change detection means for detecting the rise of the telephone line voltage. The hold state by short-circuiting the telephone line with a resistor when the detachment detection means for detecting attachment / detachment of the telephone by the device and the rise detection signal from the voltage change detection means and the detachment detection signal for the telephone from the attachment / detachment detection means When the connection detection signal of the telephone is obtained from the attachment / detachment detection means, A hold control circuit consisting of hold means for resetting the staying state is provided, and when the insertion plug is pulled out from the telephone outlet, the hold control circuit operates to automatically set the telephone line to the hold state and call. Since the hold status is automatically reset when the plug is reconnected to the outlet, the phone can be moved easily even during a call, and the plug can be pulled out from the telephone line. It is possible to achieve the hold function without affecting the telephone line because it is detected by a change in the impedance of the control line instead of a short circuit in the telephone line. There is an effect that the holding means does not malfunction sometimes.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of a main part of the same, FIG. 3 is an operation explanatory diagram of the same, and FIG. 4 is a schematic configuration diagram of a conventional example. 1 is a telephone outlet, 2 is a telephone, 3 is an insertion plug, 4 is an impedance element, 6 is a voltage change detecting means,
Reference numeral 7 is an attachment / detachment detecting means, 8 is a holding means, and 9 is a holding control circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Takeyama 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References: 60-60557 (JP, U)

Claims (1)

[Claims] 1. In a telephone system in which a telephone call position can be freely selected by connecting a plug of a telephone to any of a plurality of telephone outlets having telephone lines, a control line is wired to the telephone outlet. An impedance element connected to the control line is provided in the plug, and a voltage change detecting means for detecting the rise of the telephone line voltage and a detachment for detecting the detachment of the telephone depending on whether or not the impedance element is connected between the control lines. When a rise detection signal is obtained from the detection means and the voltage change detection means and a telephone removal detection signal is obtained from the attachment / detachment detection means, the telephone line is short-circuited by a resistor to set the holding state and the attachment / detachment detection means. Hold to reset the hold state when the phone connection detect signal is received Telephone system which is characterized in that a hold control circuit further comprising a stage.