JPH0363862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a telephone switching device that switches and connects a public telephone and a general subscriber telephone to a public telephone line.

[Prior art]

Conventionally, in the case of small pink telephones, the signal sent from the exchange side changes polarity depending on the response of the called party, as shown in FIG. 1 (A). At this time, the inserted coins are simultaneously stored and mutual communication becomes possible, and the signal from the exchange side remains inverted from then on.
On the other hand, since general subscriber telephones also perform the same polarity reversal operation as shown in Figure 1, by adding a switching device to the public telephone line, it is possible to It was also possible to make and receive calls.

However, with the introduction of the wide-area time and minute system, there was a shift from traditional public telephones to indoor desk public telephones (large pink telephones) for new services.
The signal from the exchange side also changed to something like the one shown in Figure 2, which changed polarity depending on the called party's response (a), and began to send periodic polarity reversal signals as coin storage signals. (b) Therefore, it is no longer possible to perform switched calls using a conventional switching device consisting of a simple switch. Therefore, as the needs for telephones change with the diversification and labor saving of society, for example, when installing a telephone in a store and residence, it is necessary to connect a public telephone line and a general telephone line, respectively. In addition to high costs, there were also problems in terms of service to users.

Therefore, an additional circuit equipped with a capacitor for smoothing the transmitting current when a polarity reversal signal arrives and a diode bridge that gives a certain polarity to this capacitor is connected in front of the regular subscriber telephone, and the transmitting current is smoothed when the polarity reversal signal arrives. A telephone device has been proposed which is provided with means for detecting interruption and preventing the formation of a loop due to the diode bridge, thereby allowing normal telephone calls to be made even from a general subscriber telephone. however,
From the perspective of improving services, it is desirable not only to be able to make calls from general subscriber telephones, but also to be able to transfer calls during calls.

[Object and structure of the invention]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a telephone switching device capable of transferring calls from the general subscriber telephone side to the public telephone side during incoming and outgoing calls.

In order to achieve such an objective, the present invention
A diode bridge DB that outputs a positive signal to one output terminal regardless of the polarity of the input signal from the exchange side, and capacitors C2 and C4 connected to the diode bridge for noise absorption and transmitting current smoothing. and an additional circuit that normally has connection terminals L1 and L2 of the public telephone line and a changeover switch SW.
1, SW2, and a switching means A, MA, ma1, ma that connects an additional circuit between this connection terminal and the changeover switch by a polarity reversal signal when the called party answers.
2, ma3, changeover switch and public telephone TEL1
In order to charge the incoming call response relay drive capacitors C6 and C7 connected between the capacitors C6 and C7 for a certain period of time with the local voltage when operating the changeover switch to transfer a call from the general subscriber telephone TEL2 to the public telephone. The capacitor for driving the incoming call response relay is connected to a changeover switch, and after a certain period of time, the capacitor for driving the incoming call response relay is connected to the public telephone in order to send out the electric charge charged in the capacitor for driving the incoming call response relay as an instantaneous polarity reversal signal. Switch means connected to L, LP, lp2, C9, C10, RV, rv1,
2, 3, and 4 are provided, and by switching the changeover switch, an instantaneous polarity reversal signal is sent to the public telephone to drive the incoming call response relay. Hereinafter, the present invention will be explained in detail using Examples.

〔Example〕

FIG. 3a is a circuit diagram showing one embodiment of the present invention, FIG. 3b is a circuit diagram showing the configuration of the commercial power supply section, and FIG.
The figure is a partially detailed diagram of a public telephone. As shown in FIG. 2, this embodiment is equipped with a general subscriber telephone set and a public telephone set for the connection terminals L1 and L2 of the public telephone line to which polarity reversal signals arrive, and a changeover switch.
SW1 and SW2 can be used to switch and connect, respectively. That is, in the figure, the public telephone TEL1 and the general subscriber telephone TEL2 are generally well-known telephones equipped with all the functions necessary for making calls, and the connection terminals T1, T2 and T are connected by switching switches SW1 and SW2, respectively.
3, connected to connection terminals L1 and L2 via T4. Note that the switches SW3 to SW5 are also switched at the same time. A response monitoring relay A is connected between the connection terminal L2 and the changeover switch SW2. On the other hand, a loop supervisory control relay MA is connected to the commercial power supply, and when the response supervisory relay A is activated by the polarity reversal signal when the called party responds and the switch a that constitutes its contact is closed, this relay Operating current flows through MA. This makes up the switch ma that makes up that contact.
1 to ma4 are switched, and an additional circuit including a diode bridge DB consisting of capacitors C2 and C4 and diodes D1 to D4 is connected together with the response monitoring relay A in front of the changeover switches SW1 and SW2. Capacitor C forming the additional circuit
4 is a transmission when a polarity reversal signal arrives, which supplies a transmitter current to the telephone during the periodic polarity reversal signal interruption time (t3, t5 in Fig. 2) as a coin storage signal to prevent a momentary audio interruption. The capacitor for smoothing the telephone current, the diode bridge DB, supplies a unidirectional current to capacitor C4 and the telephone regardless of the polarity of the signal coming from the exchange side, and ZD1 and ZD2 are used to make capacitor C4 smaller. A constant voltage diode for terminal voltage control, C1 and C3 are capacitors for DC blocking, C2 is a capacitor for absorbing noise caused by the rise and fall of the polarity reversal signal,
CH1 is a check coil for preventing short circuit of the audio signal due to capacitor C2, and CH2 is a check coil for preventing short circuit of the audio signal due to capacitor C4.The components of these additional circuits are the same as those commonly used in public telephones. It is. Note that DB1 is a diode bridge that maintains the direction of current flowing through each subsequent relay regardless of the polarity of the commercial power supply voltage.

In the above configuration, when making a call from the general subscriber telephone TEL2, the following loop is formed.
When the loop detection relay L connected between the switch SW1 and the connection terminal T3 operates, the switch L that constitutes its contact in the control circuit of the commercial power supply closes, so the transistor Tr1 becomes conductive.
Relay LP works. As a result, the switches lp1 to lp4 forming the contacts are switched. D5 is a diode.

L1(+)−ma1−ma2−SW1−L−T3 −TEL2−T4−D5−ma3L−L2(-) …(1) Next, relay A operates as follows by the polarity change signal when the called party answers. Then, as described above, relay MA is operated by the control circuit of the commercial power supply section.

L2(+)−ma3−A−SW2−T4−TEL2 −T3−L−SW1−ma2−ma1−L1(−) …(2) This allows additional circuits including capacitors C2, C4, diode bridge DB, etc. Connected within the loop.

L2(+)−D3−CH2−ma2−SW1−L −T3−TEL2−T4−D5−ma3−D2 −CH1−ma1−L1(−) …(3) At this time, relay A is connected in parallel. Although the relay MA recovers by being short-circuited by the diode D5, the relay MA is self-held by the self-contact (ma4) and continues to operate. So the polarity is L1
When it becomes (+), L1(+)−ma1−CH1−D1−CH2−ma2 −SW1−L−T3−TEL2−T4−D5 −ma3−D4−L2(−) …(4) After that, during polarity reversal is a loop of (3), and during L1 (+) is a loop of (4)
The call can be continued in the loop. Further, during the interruption time of the polarity reversal signal (t3, t4 in FIG. 2), the transmitting current is covered by the discharge of the capacitor C4 that was charged during the polarity reversal (simultaneously with the formation of the loop 3).

C4(+)−CH2−ma2−SW1−L−T3 −TEL2−T4−D5−ma3−SW3 −C4(−) …(5) When the handset is lowered, relay L is restored, so relay Lp and relay MA is restored and capacitor C2,
Disconnect the additional circuits including C4 and diode bridge DB from the loop and restore the exchange. The reason why the loop detection relay L is provided to disconnect the additional circuit during on-hook is to prevent the diode bridge DB from forming a loop even during on-hook. The reason why this additional circuit is connected at the polarity reversal signal when the called party answers is because if it is connected immediately by off-hook operation, the dial pulse will be distorted by capacitors C2 and C4, and because there is no need to connect it at the time of an incoming call. . An incoming call is made as follows.

L1(+)−ma1−ma2−SW1−L−T3 −TEL2−T4−D5−ma3−L2(−) …(6) Then, while talking on the general subscriber telephone TEL2, call this to the public telephone TEL1. The operation when transferring will be explained.

First, in the case of call forwarding, as is clear from loop 6, relay L operates, but relay A does not operate because there is no polarity reversal signal, so relay LP is the only relay in the commercial power supply section. This means it is working. Therefore, switch SW1 was set for transfer.
~Even when SW5 is switched, relay LP remains in the operating state for a while due to capacitors C9 and C10, so switches SW1 and SW2 are switched during that time.
Incoming call response relay drive capacitor C connected between
6, C7 with diodes D6, D7 and resistor R
4, the local voltage is charged via R5 as follows.

L1(+)−ma1−ma2−SW1−lp2 --- | | | ---D6−R4−C6—— D7−R5−C7−rv2— | | | ) …(7) Here, the switches rv1 and rv2 are rv3 and
Similar to rv4, it constitutes the contact point of the instantaneous polarity reversal signal sending relay RV.

Next, when the discharge of the capacitors C9 and C10 is completed and the relay LP is restored, the relay RV on the commercial power supply side is instantaneously activated by the discharge current of the capacitor C13 sent through the resistor R13.

C13(+)−R13−RV−lp4−C13(-) …(8) The operation of this relay RV causes switches rv1 to rv
4 is switched and capacitors C6 and C7 are public telephones.
connected in series with TEL1, resulting in capacitor C
An instantaneous polarity reversal signal is sent to the public telephone TEL1 as a discharge current of 6 and C7, and drives the incoming call response relay R.

In FIG. 4, r1 and r2 are switches configuring the contacts of the incoming call response relay R, HS1,
HS2 is a switch, T is a transmitter, and INDUC.
is a guiding wire. When transferring, switch SW1
~Prior to switching SW5, call the public phone in advance.
To raise the handset of 1, press the switch.
Both HS1 and HS2 are in a state opposite to that shown. The details of the communication circuit have been omitted.

Here, since the public telephone TEL1 is a generally well-known telephone, that is, a back-loop public telephone, as described above, a telephone call circuit cannot be formed simply by off-hooking the handset. When making a call, a coin is inserted after off-hook and the coin contact cc is closed to form a call circuit, but when a call is received, a call response relay R is activated by a ring signal of 16 Hz, 75 from the station to form a call circuit. There is. A ringing signal from the station is input, and when off-hook is performed based on this, the hook switch HS2 is switched and a ringing signal current flows through the incoming call response relay R. The calling signal is an AC signal, but it operates when the connection terminal L2 of the public telephone line is energized (+),
Thereafter, the operating state is maintained magnetically. Contacts r1 and r2 are switched by the operation of the incoming call response relay R,
The coin contact cc is bypassed to form an incoming call circuit. It would be better if the same signal as the ringing signal could be generated when switching the switch, but since the circuit would be complicated, the present invention generates an instantaneous polarity change signal, sends this signal to the public telephone, operates the incoming call response relay R, and then operates the call circuit. We are trying to form a

Due to the operation of the incoming call response relay R, the incoming call can be continued in the next loop when the instantaneous operation of the relay RV ends.

When the handset is lowered, relay R is restored, and since the loop is broken, relay A is also restored.

Next, in the case of outgoing call transfer, if a paid outgoing call is in progress, relays LP and MA of the commercial power supply section are operating as described above. Even when switches SW1 to SW5 are switched for transfer, relay LP remains active for a while due to capacitors C9 and C10.
maintains its operation, so while the contact lp1 is open, the capacitors C6 and C7 are charged with the local voltage as follows.

L1(+)−ma1−CH1−D1−CH2−ma2−SW1−lp2 --- | -ma3-D4-L2(-)...(11) When relay LP is restored, relay RV instantaneously operates due to the loop in (8).

Due to the operation of this relay RV, capacitor C6,
An instantaneous polarity change signal is sent to the public telephone TEL1 as a discharge current of C7, and the incoming call response relay R is driven.

C7(+)−R5−rv2−C6(−)−C6(+)−R4−r
v1−SW2− A−ma3−D2−D1−CH2−ma2−SW1−rv3−T2 −TEL1−T1−rv4−C7(−) …(12) After the instantaneous operation of relay RV ends, communication begins in the next loop. can continue.

L1(+)−ma1−CH1−D1−CH2−ma2−SW1−rv3− T1−TEL1−T2−rv4−rv2−rv1−SW2−A−ma3
-D4-L2(-)...(13) The signal path inside the public telephone is an incoming call circuit similar to the loop in (10). Note that the operation of relay A at this time allows relay MA to maintain its operating state.

When the handset is lowered, relay R is restored, relay A is restored by cutting off the transmitting current, and relay MA is also restored, completely breaking the loop with the station.

When making and receiving calls from the public telephone TEL1 side, relay A operates, but relay LP,
MA and RV do not work, so you can make and receive calls normally as a regular public telephone. Also, public telephones
For transfer from TEL1 to general subscriber telephone TEL2,
This can be done freely during both incoming and outgoing calls.

Incidentally, in the above configuration, two capacitors C6 and C7 are provided to drive the incoming call response relay R, and this is for the following reason. In other words, general subscriber telephone TEL2
When transmitting a call from the telephone to the public telephone TEL1, it is necessary to add a circuit equipped with a capacitor C2 for noise absorption and a capacitor C4 for smoothing the sending current even after the transmission. As mentioned above, public telephones are naturally equipped with such an additional circuit, but it is usually necessary to make calls using coins or a special key. The circuit configuration is such that they are not added when the incoming call response relay R operates, that is, when there is an incoming call, since they are unnecessary. In the present invention, as described above, since the incoming call response relay R is driven to form a loop even during outgoing call transfer, the original additional circuit does not function, and therefore it is necessary to add a separate circuit. In this way, relay R
It is not possible to secure a sufficient voltage to charge the driving capacitor (only about a few volts can be obtained), and the relay R cannot be driven as it is. Therefore, when charging the drive capacitors C6 and C7, it is necessary to temporarily disconnect the additional circuit and charge the capacitors with the local voltage. For this purpose, the open state of switch LP1, which constitutes the contact point of relay LP, is used, and after switches SW1 to SW5 are switched, the above-mentioned additional circuit is disconnected while relay LP is operating, and capacitors C6 and C7 are charged during that time. I did it like that. In this case, if the additional circuit is disconnected for a long time, the exchange will be restored, so charging must be completed in a short time. For this purpose, two capacitors were used, and when charging they were connected in parallel to shorten the charging time, and when discharging they were connected in series to obtain enough voltage to drive relay R. . Of course, the number of capacitors for driving the incoming call response relay R is not limited to two, and the more the better, but since the number of contacts of the relay RV is limited to four, two capacitors are used here. In addition,,
At the time of discharging, the switch lp1 is restored and in the closed state, so no circuit via the local power supply is formed. In this way, capacitors C6 and C7 are required for outgoing call transfer, and if only to enable incoming call transfer, there is no need to connect the above additional circuit, and therefore the local voltage can be used as is. Therefore, one capacitor for driving the incoming call response relay is sufficient.

For calls made at public telephone TEL1 after the call is transferred,
This will be done in the incoming call circuit after relay R is activated, but in this case relay MA is activated,
In addition, since switch LP1 is also closed, the additional circuit is connected to the front end, allowing normal communication.

In addition, as mentioned above, the additional circuit is disconnected while the relay LP is operating, and the capacitor C is
6. I tried to charge C7, but this relay
If the LP recovery takes longer than necessary, the exchange will recover. Therefore, a variable resistor VR is provided to adjust this recovery time. Also, switch
SW5 was installed to lengthen the recovery time of the relay LP to prevent the relay LP from fluttering when dialing when it is connected to the general subscriber telephone TEL2 side, and to prevent the relay LP from fluttering when the switch is switched for transfer as described above. This is to speed up the recovery of the relay LP and lengthen the recovery time of the relay MA, as described above.

〔Effect of the invention〕

As explained above, according to the present invention, a capacitor for driving an incoming call response relay is provided, and after charging the capacitor with a local power source when transferring a call from a general subscriber telephone to a public telephone, the capacitor is connected to a public telephone and a public telephone is connected to the public telephone. By configuring it to send an instantaneous polarity reversal signal to the telephone, and by connecting an additional circuit including a noise absorbing capacitor and a transmitting current smoothing capacitor, etc. before the changeover switch, it is possible to By activating the incoming call response relay of the public telephone and forming an incoming telephone circuit,
Both outgoing and incoming calls can be transferred to the public telephone.

[Brief explanation of drawings]

Figure 1 is a diagram showing a signal arriving from the exchange side for a conventional small pink telephone, and Figure 2 is a diagram showing a periodic polarity change signal arriving for an indoor desk public telephone (large pink telephone). ,,Figure 3a,b
4 is a circuit diagram showing one embodiment of the present invention, and FIG. 4 is a partially detailed diagram thereof. TEL1...Public telephone, TEL2...General subscriber telephone, L1, L2...Public telephone line connection terminal, R...
Incoming call response relay, C6, C7...capacitor for driving incoming call response relay, C1-C4...capacitor configuring additional circuit, CH1-CH2...chiyoke coil,
DB...Diode bridge, SW1-SW5...Selector switch, ma1-ma3...Switch for connecting the additional circuit, rv1-rv4...Switch for switching and connecting the capacitor for driving the incoming response relay.

Claims (1)

[Claims] 1. A public telephone line to which a periodic polarity change signal arrives,
A diode that outputs a positive polarity signal to one output terminal regardless of the polarity of the input signal from the exchange side, in a telephone switching device equipped with a switch that switches and connects a public telephone set with an incoming call answering relay and a general subscriber telephone set. An additional circuit including a bridge and a capacitor connected to the diode bridge for noise absorption and smoothing of the sending current, and a connection terminal of the public telephone line and the above changeover switch are normally connected to answer the called party. a switching means for connecting the additional circuit between the connection terminal and the changeover switch in response to a polarity reversal signal at the time; a capacitor for driving an incoming call response relay connected between the changeover switch and the public telephone; When transferring a call from a general subscriber telephone to a public telephone by operating the switch, connect the capacitor for driving the incoming call response relay to the changeover switch for a certain period of time, and then switch off the capacitor for driving the incoming call response relay after the certain period of time has passed. and switch means for connecting to a public telephone, and the capacitor for driving the incoming call response relay is charged with the local voltage when connected to the changeover switch, and uses the charged electric charge as an instantaneous polarity reversal signal when connected to the public telephone. A telephone switching device characterized by transmitting.