JPS6058766A - Telephone switching device - Google Patents

Abstract

PURPOSE:To transfer a call from the side of a general subscriber's telephone set, which is in course of call terminating, to the side of a public telephone set, by providing a circuit which transmits a momentarily polarity-inverted signal to the public telephone set when the busy general subscriber's telephone set is switched to the public telephone set with switches. CONSTITUTION:Changeover switches SW1 and SW2 between both telephone sets have a lock position LA of the side of a general subscriber's telephone set TEL2, a lock position LB of the side of a public telephone set TEL1, and a non-lock positon NL, and a non-lock switch K1 and switches S1-S3 are operated in order while switches SW1 and SW2 are returned to the position LB after they pass the position LB from the position LA to reach the position NL. In case of transfer, the handset of the telephone set TEL1 is hooked off preliminarily. First, when switches are switched from the position LA to the position NL, a capacitor C7 is charged through the switch K1, and simultaneously, capacitors C1 and C2 of the public telephone set are charged. Next, switches S1-S3 are switched, and the momentarily polarity-inverted signal is transmitted to the telephone set TEL1 by discharging of the capacitor C7 and etc., and an incoming response relay R is operated to form a terminating speaking circuit of the telephone set TEL1, and switches are returned to the position LB to make the call possible.

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 called party's response, 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 operate in the same manner as shown in Figure 1, by adding a switching device to the public telephone line, calls can be made both from the public telephone and from the regular telephone. Incoming calls were possible.

However, with the introduction of wide-area time division, there was a shift from conventional public telephones to indoor desk public telephones (large pink telephones), which offered a new service, and at the same time, the signals from the exchange changed to those shown in Figure 2. In addition to changing the polarity in response to the called party's response (a), a periodic polarity reversal signal is now sent out as a coin storage signal (←), so the switching device consisting of a simple changeover switch is no longer required. Now I can't make a switched call. 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 separately, which reduces costs. As prices increased, 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 to the front of the regular subscriber telephone, and the telephone current is cut off by on-hook. A telephone device has been proposed which is provided with means for detecting the above-mentioned diode bridge and preventing the formation of a loop, 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 of the present invention is to provide a telephone switching device capable of transferring an incoming call from the general subscriber telephone side to the public telephone side.

In order to achieve such an object, the present invention is provided with a circuit that sends an instantaneous pole reversal signal to a public telephone when switching from a general subscriber telephone to a public telephone.

That is, by transmitting an instantaneous polarity reversal signal, the incoming call response relay of the public telephone is operated to form an incoming call circuit. Hereinafter, the present invention will be explained in detail using Examples.

〔Example〕

FIG. 3 is a circuit diagram showing one embodiment of the present invention, and FIG. 4 is a partially detailed diagram of a public telephone. In this embodiment, the connecting terminal L1. of the public telephone line to which the more polarity inversion signal shown in FIG. 2 arrives. , L2 is equipped with a general subscriber telephone and a public telephone, and has a changeover switch SWI.

Switching connection can be made using SW2. That is, in the figure, the public telephone installation I and the general power supply device 2 are generally well-known telephones equipped with all the functions necessary for telephone calls, and the switches SWI and S
By switching W2, connection terminals TI, T2 and T3 . Connection terminal Ll via T4.

Connected to L2.

Here, as shown in FIG. 5, the changeover switch between the two chargers is in the lock position LA on the general subscriber charger Z side, the lock position LB on the public telephone I side, and the non-lock position NL.
, and when transferring from the general subscriber power supply device 2 to the public telephone installation L, first move to the non-lock position N as shown in the figure.
After tilting it to the L side, fix it in the lock position LB. The position indicated by tp in the figure is the cutting point of the switches SWI and SW2, but once they pass the lock position LB, they move to the non-lock position NL.
1 is activated in the non-lock switch as shown by ■ in the figure, and then ■ returns to the lock position LB.
The configuration is such that the switches 81 to S3 operate as shown in FIG. In other words, there are 5 switches on the break contact side and make contact side of switches SWI and SW2, and 8 switches on the switch.
Break contact side of 1 to S3, make contact (non-lock)
When transferring data from the general access power supply device 2 side to the public telephone installation L side, the side performs operations as shown in the time charts of FIGS. 6(,) to (,). On the other hand, the transfer from the public telephone installation I side to the general access power supply device 2 side is simply by flipping the switches SWI and SW2 from the lock position LB to the lock position LA, as shown by ■ in Fig. 5. The break contact side and the make contact side only perform the operations shown in Figs. 7(,) and (b). Note that FIG. 6(f) shows the operation of the incoming call response relay as described later, and FIG.
) and FIG. 7(C) show the timing at which a call becomes possible.

By the way, in FIG. 3, a magnetic launch type response monitoring relay M is connected between the connection terminal T3 on the general subscriber telephone side and the connection terminal L1 of the public telephone line. The contacts indicated by ml-mfi in the figure all constitute the contacts of this relay M, and when relay M operates, a circuit including capacitors C2, C4 and diode bridge DB consisting of diodes D1 to D4 is inserted into the loop. connected to. PCI is a photocoupler made up of a light emitting diode LD and a phototransistor PT, and Tri is a transistor that constitutes a loop detection circuit that detects interruption of communication current.

The capacitor C4 constituting the additional circuit is used to control the interruption time of the periodic polarity change signal as the coin storage signal (ts, t5 in Fig. 2).
The diode pringe DB, which is a capacitor for smoothing the transmitting current when a polarity reversal signal arrives, supplies the transmitting current to the general power supply device 2 to prevent momentary voice interruptions, regardless of the polarity of the signal from the exchange side. Capacitor C4 and a capacitor that allows one-way current to flow through the general power supply device 2, CI and C3 are DC blocking capacitors, C2 is a capacitor for absorbing noise caused by the rise and fall of the polarity reversal signal, CHI and CH
2 is a choke coil for preventing audio signal short circuit by capacitors C2 and C4, and the components of these additional circuits are as follows:
It is exactly the same as those commonly used in public telephones. Further, C5 to C6 are capacitors, D5 to D7 are diodes, R1 to R6 are resistors, ZDI to ZD4 are constant voltage diodes, and 5CRI is a thyristor.

In the above configuration, when making a call from the general access power supply device 2 side, after the called party response signal relay M operates, the loop is (1) during polarity change, and the loop is (2) during Ll (g). ), during the interruption period (ta, ts in Figure 2), (3)
The call is maintained in a loop.

L plane ÷ SW2-m3-CHI-D4-PCI (LD)
-R1-CH2-m4-T4-2-T3-m2-DI
-ml-m5-8WI-Ll(-)...(1) Ll(+)-SWI -m5-ml-D2-PCI (
LD)-R1-CH2-m4-T4-2-T3-m2
-D3-CHI-m3-8W2-L2(-)...
(2) C4(g)-D5-PCI(LD)-R1-CH2-m
4-T4-TET, 2-T3-m2-C4(-) ・-
(3) When the handset is lowered, the light emitting diode LD stops emitting light due to the cutoff of the communication current, which prevents the diode bridge DB from forming a loop, and a recovery current flows through the relay M as follows.

(4) In this way, it is possible to normally make an outgoing call from the general power supply device 2 side, but an incoming call can also be made as follows.

In this case, a periodic polarity reversal signal for storing coins does not arrive, and there is no need to connect additional circuits including capacitors C2 and C4, diode bridge DB, and the like.

Ll←)SWI-D6-ml-m2-T3-place 2-T4
-m4-m3-8W2-L2 (-) ... (5) Of course, switch SWI and SW2 are connected to public telephone Ta.
By switching to the 17- side, it can be used normally as a normal public telephone.

Therefore, next, an explanation will be given of the operation when a call received on the first pattern filling device 2 side is transferred to the horizontal public telephone I side during a call. In addition, in Figures 3 and 4, C7
is a capacitor, DB is a diode, and R4 is a resistor. By providing this capacitor C7, when the switch is switched, an instantaneous polarity reversal signal is sent to the horizontal public telephone I and the incoming call response relay is activated. An incoming circuit can be formed. In the horizontal public telephone I, R is the incoming call response relay, rl and r2 are the contacts, H8I and H82 are the hook switches, T is the transmitter, and I
NDUC is a guide wheel. Note that details of the communication circuit have been omitted.

When transferring, the handset on the horizontal public telephone I side is raised in advance before switching the foot changeover switch as shown in FIG.

So, first of all, select switch SWI.

By switching SW2 to the non-lock position NL side,
The capacitor C7 is charged by -8= through the switch.

Ll(+)-8WI-Kl-DB-R4-C7-81-
8W2-L2(-)...(6) At this time, as mentioned above, since the handset of the public telephone is raised, the capacitors CI and C2 of the public telephone are also charged at the same time.

When the switches SWI and SW2 are fully turned to the non-lock position NL, the capacitor switches 81 to S3 are switched, and the capacitor 07 etc. are discharged, and an instantaneous polarity reversal signal is sent to the horizontal public telephone L, as shown in FIG. 6(f). The incoming call response relay R operates as follows.

C7 (→-8l-8W2-L2-inside-Ll-8WI-
82-T2...(8) This forms the incoming call circuit for the horizontal public telephone I,
By returning the switches SWI and SW2 to the lock position LB, a telephone conversation becomes possible as shown in FIG. 6 ω).

In this way, from the general access power supply device 2 to the public telephone device L
You can transfer incoming calls to.

On the other hand, the transfer from the public telephone device I to the general subscriber charging device 2 can be freely performed either during an incoming call or an outgoing call. By switching the switches SWI and SW2, a call can be made as shown in FIG. 7(C).
If an incoming call is in progress, the call can be continued using the loop described in (5) above. During an outgoing call, the call is first made using the loop described in (5) above, and after relay M is activated by the polarity reversal signal, the above (5) loop is used.
The call can be continued in the loop of 1) to (3).

Note that it is not possible to transfer a call from a general subscriber telephone to a public telephone during an outgoing call, but this is due to capacitors C2 and C4.
Because additional circuits such as the above are inserted between the switches and between SW2 and the general subscriber telephone, when switching to the public telephone side, these functions are lost and a complete call cannot be made. As a supplement, capacitor C for noise absorption
As mentioned above, public telephones are originally equipped with capacitors 2 and 04 for smoothing the transmitting current (see Figure 4), but they are not suitable for making paid calls using coins or special keys. If the incoming call response relay R operates (that is, in the case of an incoming call),
They have a circuit configuration that does not contribute to loop formation. Therefore, the transfer method performed by operating the relay R as described above cannot make them function normally.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a circuit that sends an instantaneous pole reversal signal to a public telephone when switching from a general subscriber telephone to a public telephone during a call,
By operating the incoming call response relay of the public telephone, an incoming call circuit is formed and the call can be continued.

[Brief explanation of drawings]

111- Figure 1 shows the signal arriving from the exchange side for a conventional small pink telephone, and Figure 2 shows the periodic polarity change signal arriving for an indoor desk public telephone (large pink telephone). 3 is a circuit diagram showing an embodiment of the present invention, FIG. 4 is a partially detailed diagram thereof, FIG. 5 is a diagram for explaining the configuration of a changeover switch, and FIGS. 6 and 7. is a time chart showing the operation thereof and the operation of the incoming call response relay R. Place I...Public telephone, Place 2...General subscriber telephone, Ll, L2...Public telephone line connection terminal, R...
...Incoming call response relay, C7...A capacitor that constitutes a circuit that sends an instantaneous polarity reversal current to a public telephone. Patent Applicant: Tamura Electric Manufacturing Co., Ltd. Representative of Nippon Telegraph and Telephone Public Corporation Masaki Yamakawa 12-

Claims (1)

[Claims] In a telephone switching device equipped with a switch that switches and connects a public telephone and a general subscriber telephone to a public telephone line to which a periodic pole change signal arrives, an instantaneous signal is sent to the public telephone when switching from the general subscriber telephone to the public telephone during a call. A telephone switching device characterized by being provided with a circuit that sends out a polarity reversal signal.