JPH0113797B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is an improvement in a button telephone device in which a main device and a plurality of key telephones are connected by each pair of signal paths, and voltage signals having voltages corresponding to various information are transmitted through the signal paths. It is related to. In such button telephone devices, as disclosed in Japanese Patent Publication No. 56-28419 filed separately by the present applicant, a voltage discrimination circuit has conventionally been provided in the main device for each button telephone. The number of voltage discrimination circuits required increases in accordance with the number of button telephones, which complicates the circuit configuration and increases the number of man-hours required for assembly, resulting in a disadvantage that the device price becomes high. In addition, in the past, voltage signals sent irregularly from key telephones were discriminated, and the discrimination results were given to the control circuit in an asynchronous state.
The configuration of the control circuit becomes complicated, which also causes the disadvantage that the cost of the device becomes high. The present invention has the purpose of fundamentally eliminating such drawbacks of the conventional technology, by providing a common voltage discrimination circuit and a voltage detection circuit corresponding to each button telephone in the main device, and making it possible to connect each voltage detection circuit and voltage discrimination circuit to the main device. The switching circuits provided between the two are sequentially turned on, and the detected voltage of each voltage detection circuit is sequentially applied to the common voltage discrimination circuit, and the output of the voltage discrimination circuit is read by the processor in accordance with this operation. A highly effective key telephone device is provided. Hereinafter, details of the present invention will be explained with reference to figures showing examples. Figure 1 is a circuit diagram showing the configuration of the main parts, and the main unit KSU has a processor such as a microprocessor.
A CPU is provided, which performs overall control operations, while a plurality of button telephones ET ₁ to
Control circuits CT _{1 to CT 5} are provided corresponding to ET 5, and voltage signals are transmitted and received between the key telephones ET ₁ to _{ET 5} . In addition, the main unit KSU and each button telephone TE ₁ ~
ET ₅ are individually connected to each other by a pair of signal paths CL ₁ to _{CL 5} provided separately from the communication path VL ₁ shown as a representative in the key telephone ET ₁ , and these are connected to each other by a control circuit. In this example, a DC voltage of 22V is applied from CT ₁ to CT ₅ in a steady state. Note that button telephones ET ₁ to _{ET 5} have a signal path.
In addition to the transmitting/receiving circuits connected to CL ₁ to _{CL 5} , there are a switch HS, a dial circuit DIA, and a telephone circuit TK connected to the communication path VL ₁ , etc., which are connected to the main communication path VL ₁ , etc. Device
It is connected to the exchange circuit (not shown in the diagram) inside the KSU. Here, the transmission status of voltage signals from the main device KSU side to the key telephones ET ₁ to ET ₅ is as follows. i.e. control circuit CT ₁ and button telephone
Taking ET ₁ as an example, in steady state, transistor Q ₂₀₁ is forward biased and turned on by resistor R ₂₀₁ , so that transistor Q ₂₀₁
The power supply voltage +24V applied to the collector of is sent to the line terminal 1D1 via the blocking wire CH,
Accordingly, the loop current flows back to the line terminal 1D2 via the line terminals _D1 and _D2 . However, in steady state, the inverter
Since the outputs of IN ₂₀₁ and IN ₂₀₃ are "H" (high level) and the transistor Q ₂₀₂ is in the off state, the voltage V ₁ between the line terminals 1D1 and 1D2
is held at approximately 22V by the value of resistor R ₂₀₁ . For this reason, the voltage regulator diode ZD ₂₀₁ with a Zener voltage of 12V is in the on state, and the resistor R ₂₀₉ ,
In order to conduct current to R ₂₁₀ and forward bias the transistor Q ₂₀₄ , the transistor Q 204 is turned on, and the transistor Q ₂₀₄ is turned on through the resistor R ₂₀₈ .
Q ₂₀₅ is turned on, and the loop current flows back to the common circuit via transistor Q ₂₀₅ . On the other hand, in the button telephone ET ₁ , since approximately 22V is applied between the line terminals D1 and D2, the constant voltage diode ZD ₃₀₄ with a Zener voltage of 20V is in the on state, and the voltage is in the on state through the resistor R ₃₀₃ . A directional bias is applied, transistor Q ₃₀₂ turns on, and the Zener voltage passes through diodes D ₃₀₂ and D ₃₀₃ .
By bypassing the 16 V constant voltage diode ZD ₃₀₃ and the 12 V Zener voltage constant voltage diode ZD ₃₀₅ , they are maintained in the off state, and the transistors Q ₃₀₁ and Q ₃₀₃ are in the off state. Also, if the processor CPU sends a code to light up the track indicator lights of the button telephones ET ₁ to ET ₅ from the output ports O ₀ to O ₅ , an "H" signal LED is sent from the latch circuit LAT having a decoding function. , the output of inverter IN ₂₀₃ is “L” (low level)
Therefore, the transistor is turned on with forward bias applied by resistors R ₂₀₆ and R ₂₀₇ .
By Q ₂₀₃ , also resistor to transistor Q ₂₀₂
A forward bias is applied through R ₂₀₅ , and one end of resistor R ₂₀₃ is connected to the common circuit through the output impedance of inverter IN ₂₀₃ , transistor Q ₂₀₂ turns on, and resistor R ₂₀₃ The base of the transistor Q ₂₀₁ is connected to the common circuit via the line voltage V ₁ to approximately 18V. Then, in the button telephone ET ₁ , the constant voltage diode ZD ₃₀₄ turns off, and the constant voltage diode ZD ₃₀₃ turns on, giving a forward bias to the transistor Q _{301 via the resistor R 302 .}
To turn it on, power is applied to the light emitting diode LE ₃₀₂ , which serves as a track indicator light, through the resistor R ₃₀₁ .
This lights up. However, at this time, the voltage regulator diode ZD ₃₀₅ is bypassed via the diode D ₃₀₄ , so the transistor Q ₃₀₃ remains off, and the voltage regulator diode ZD ₃₀₄ is turned off, so the transistor Q ₃₀₂ switches to the off state. Furthermore, if the processor CPU sends out a code to make the speaker SP of the key telephone ET ₁ ring from the output ports O ₀ to O ₅ , an "H" signal SP ₁ is sent from the latch circuit LAT, and the inverter
In order to set the output of IN ₂₀₁ to "L" and the output of inverter IN ₂₀₃ to "H", transistor Q ₂₀₂ turns on and one end of resistor R ₂₀₂ is connected to the inverter.
It is connected to the common circuit through the output impedance of IN ₂₀₁ , and the base of the transistor Q ₂₀₁ is connected to the common circuit through the resistor R ₂₀₂ to maintain the line voltage V ₁ at approx.
Set to 14V. Then, in the button telephone ET ₁ , the constant voltage diodes ZD ₃₀₃ and ZD ₃₀₄ are turned off, and the transistors Q ₃₀₁ and Q ₃₀₂ are also turned off, while the constant voltage diode ZD ₃₀₅ is turned on, and the resistors R ₃₀₄ and R ₃₀₅ are turned off. applies a forward bias to the transistor Q ₃₀₃ and turns it on, thereby closing the power supply return path of the signal amplifier SA via the diode D ₃₀₅ , which becomes operational. Therefore, if an alternating current calling signal is applied between line terminals 1D1 and 1D2 from a signal generator (not shown), this signal will be transmitted through the circuit of capacitor C ₃₀₂ , potentiometer RV ₃₀₁ and resistor R ₃₀₇ . The signal is then applied to the signal amplifier SA, where it is amplified to a predetermined power level, and then drives the speaker SP to make it ring as a ringing signal. As described above, from the main device KSU to the button telephone
Transmission of a voltage signal to ET ₁ and reception of the voltage signal at button telephone ET ₁ are carried out, while transmission of a voltage signal from button telephone ET ₁ and reception of this at main unit KSU are carried out as follows. That is, in the button telephone ET ₁ , a diode D ₃₀₁ for a reverse polarity voltage bypass is connected between the line terminals D ₁ and D ₂ , and the central line button K ₁ and
An extension button K ₂ and a remote button K ₃ for calling a two-wire telephone separately housed in the main unit KSU are connected in parallel, and the extension button K ₂ is connected to a constant voltage of Zener voltage 4.7V. A diode ZD ₃₀₁ is inserted in series, and a constant voltage diode ZD ₃₀₂ with a Zener voltage of 9.1 V is inserted in the remote button K ₃ .
are inserted in series. For this reason, line terminal D
The line voltage V ₂ between 1 and D2 is 0 V when the office line button K ₁ is turned on, and approximately 0 V when the extension button K ₂ is turned on.
4.7V, about 9.1V when remote button K ₃ is turned on
becomes. On the other hand, in the control circuit CT ₁ , each button K ₁
~ If any of K ₃ turns on, the line voltage V ₁
Since the voltage is about 9.1V or less, the voltage regulator diode
ZD ₂₀₁ is turned off and accordingly the transistor
Q ₂₀₄ , Q ₂₀₅ , and Q ₂₀₃ turn off, and the loop current passes through resistor R ₂₁₁ as a voltage detection circuit, resulting in a terminal voltage V _D given by: V _D =22V−V ₂ ...(1) On the other hand, a voltage discrimination circuit is provided which is composed of a comparator CP and resistors R ₁₀₃ to R ₁₀₇ ;
A transistor Q ₂₀₆ as a switching circuit is provided between R ₂₁₁ and the processor CPU.
When the "L" gate pulse sent from the output port ₀ of the inverter IN ₁₀₁ becomes "H" and is applied to the base of the transistor Q ₂₀₇ , it is turned on and the resistors R ₂₁₂ and R ₂₁₃ are turned on. In order to apply a forward bias to the transistor Q ₂₀₆ by the circuit and turn it on, the terminal voltage V _D through the diode D ₂₀₁ is divided by the resistors R ₁₀₁ and R ₁₀₂ , and becomes the voltage V _X before being applied to the comparator. Given to one input of CP. The same applies to each of the control circuits CT ₂ to CT ₅ , and as shown in FIG. 2 using the waveforms of each part in FIG. 1 as a timing chart, the output port
From R ₀ to ₄ , “L” gate pulses a to
Since e is sent out, the terminal voltages V _D in the control circuits CT ₁ to CT ₅ are sequentially scanned and applied to the voltage discrimination circuit. Further, the other input of the comparator CP is given a reference voltage _VS obtained by dividing the power supply voltage +24V by resistors R ₁₀₃ to R ₁₀₇ , and one end of the resistors R ₁₀₄ to _{R 107} is The selection pulses f to i shown in Figure 2 are the gate pulses a from the output ports P ₀ to P ₃ of the processor CPU.
It is sent out in synchronization with ~e, and is inverted by the driver DR and given after becoming "L", so that the resistors R ₁₀₄ to _{R 107} correspond to the selection pulses f to i.
One end of the driver DR is sequentially connected to the common circuit via the output impedance of the driver DR, and the reference voltage V _S changes into four types depending on the selection pulses f to i. Therefore, the reference voltage V _S is determined according to the terminal voltage V _D when each button K ₁ to _{K 3} is turned on, and
If it is assumed that a comparison output of "H" is generated under the condition of V _S < _V It will be done. Note that 4-bit serial data has the state shown in the following table.

[Table] Therefore, if the processor CPU reads the output of the voltage discrimination circuit for each gate pulse a to e and in synchronization with the selection pulse f to i, the transmission information for each button telephone ET ₁ to _{ET 5} will be transmitted. can be judged. Note that the period t of gate pulses a to e is set to the maximum
If you set it to about 50msec, the button telephone ET ₁ ~
Irregular voltage signals from the ET ₅ side can be judged with a response speed that does not pose any practical problem. In addition, the monitor button K ₄ on the button telephone ET ₁ is used to monitor the voice of the call, and when this button is turned on, the power supply return path of the monitor amplifier MA is closed by the contact K ₄ ¹ , which is in the operating state. and the light-emitting diode LE ₃₀₁ lights up, while the communication loop is closed by the contact K ₄ ² , and the voice picked up by the transformer T is monitored by the circuit of the potentiometer RV ₃₀₂ and the resistor R ₃₀₈ . The signal is applied to the amplifier MA, where it is amplified to a predetermined power level and then drives the speaker SP. However, the configuration of control circuits CT ₂ to CT ₅ is the control circuit
The configuration of the key telephones ET ₂ to _{ET 5} is the same as that of the button telephone ET ₁ , and _the operating conditions thereof are also similar to those of the control circuit CT ₁ and the button telephone ET ₁ . Therefore, by providing only one common voltage determination circuit, the purpose can be sufficiently achieved, and gate pulses a to e and selection pulses f to i
Because data is read in synchronization with
The circuit configuration is simplified and the cost of the device can be easily reduced. However, an analog switch or the like may be used as the switching circuit using the transistor Q ₂₀₆ , and depending on the situation, the voltage dividing circuit using the resistors R ₁₀₁ and R ₁₀₂ may be omitted. The present invention can be modified in various ways, such as the voltage being arbitrarily selected within a range that allows each voltage to be determined. As is clear from the above description, the present invention simplifies the configuration of the main device, reduces assembly man-hours, and reduces device costs. A remarkable effect is obtained in telephone equipment.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a timing chart showing waveforms of various parts in FIG. KSU...Main unit, CT ₁ to CT ₅ ...Control circuit,
ET ₁ to ET ₅ ... button telephone, CL ₁ to _{CL 5} ... signal path, VL ₁ ... speech path, R ₁₀₃ to _{R 107} , R ₂₁₁ ... resistor, Q ₂₀₆ ... transistor, CP ... comparison vessel,
CPU...Processor, _K1 to _K3 ...Button,
ZD ₃₀₁ , ZD ₃₀₂ ... Constant voltage diode.

Claims (1)

[Claims] 1 The main device and a plurality of key telephones are connected by a pair of signal paths each to which a direct current voltage is applied separate from the communication path, and each has a voltage corresponding to the various information transmitted by the signal path. A button telephone device that receives a voltage signal in the main device and discriminates the various information according to the voltage, comprising: a voltage detection circuit provided in the main device corresponding to each of the button telephones; a common voltage discrimination circuit provided in the main device that discriminates the voltage of the voltage signal detected by the circuit; and a switching circuit provided individually between each of the voltage detection circuits and the voltage discrimination circuit; , and a processor that sequentially turns on each of the switching circuits and reads the output of the voltage discrimination circuit accordingly.