JPS58106937A - Transmitting method for call signal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a subscriber circuit of a telephone exchange, and more particularly to a method for transmitting a paging signal to a subscriber terminal via a subscriber line.

FIG. 1 is a circuit diagram showing an example of a conventional calling signal sending circuit. DC current is supplied to the subscriber terminal 1 from a current supply circuit 3 via a subscriber line 2. Signals such as voice information are sent to and received from the subscriber terminal 1 via the subscriber line 2 and the current supply circuit 3 with the exchange main body (not shown).

On the other hand, prior to transmitting and receiving voice information signals to the subscriber terminal 1, a paging signal source 5 is connected to one line 6 via a resistor R2 and a negative signal to send a paging signal via a resistor R1 and a switch 4. A power supply 7 is connected to the other line 8. The switch 4 has transfer contacts operative to switch between the ringing signal source 5 and the ground air.

FIG. 2 is a waveform diagram showing the state of sending a calling signal to the subscriber terminal 1, which consists of a period 9 in which earth air is sent out, a period 10 in which an alternating current signal, that is, a calling signal is sent out, and a period 10 in which an alternating current signal, that is, a calling signal is sent out. Various call signals can be realized by appropriately selecting combinations.

In such a conventional calling signal sending circuit, when the switch 4 switches from the calling signal source 5 to the ground, the line 6 is connected to both the calling signal source 5 and the ground via the resistor R for a certain period of time. A disconnected state occurs. At that time, subscriber line 2
The voltage of the paging signal source 5 at the time when the switch 4 is opened remains in the portion that was electrically connected to the paging signal source 5 of the subscriber terminal 1 or the like until just before.

This residual voltage gradually starts discharging due to the leakage resistance of the subscriber line 2, etc., and therefore has a frequency component extremely close to direct current. For this reason, there is a drawback that a circuit (not shown), which is connected to both ends of the resistor R1 and which operates and stops the calling signal when the voltage at both ends exceeds a certain value, may be operated by mistake. It had

In order to eliminate the situation in which the contacts of the switch 4 are not connected to either the call signal source 5 or the earth, a semiconductor switch having a current self-holding function may be used.

However, when a switch with such a current self-holding function is used to alternately open and close the switch to switch between two signals, a situation occurs where both signals are simultaneously applied for a certain period of time. .

That is, in the case of a calling signal sending circuit, the calling signal and the earth signal collide in a short-circuited form with low impedance.
This had the disadvantage of destroying the switch.

It is an object of the present invention to prevent the parts that were electrically connected to the ring signal source until just before from being charged to a potential below ground level even when the ringing signal is paused, and to prevent the ringing signal from being discontinued. An object of the present invention is to provide a method for transmitting a calling signal that avoids collision with a geosignal.

In order to achieve the above object, the present invention alternately sends out a calling signal and a ground signal to a subscriber line via a current self-holding semiconductor switch, when the sending of the calling signal is completed and the The earth signal is sent out after the turn-off time of the current self-holding semiconductor switch has elapsed.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a circuit diagram of a current sending circuit to which an embodiment of the present invention is applied. In the following drawings, parts that are the same as those shown in FIG.

Reference numerals 11 and 12 indicate semiconductor switches each having a current self-holding function, which correspond to a pair of switches 4 shown in FIG. 1. The semiconductor switches 11, 12 each include pnpn) transistors 11a, llb and 1.
2a and 12b are connected in antiparallel. Reference numeral 13 designates a first dart drive circuit 13a that drives the exclusive operation circuit T1 and a second dart drive circuit 13b that drives the semiconductor switch 12.O15 is a detection circuit that drives the semiconductor switch 11.12. detects the open or closed state of the circuit and transmits the state to the control circuit 14. A control signal from the control circuit 14 is transmitted via the first delayed dart circuit 2 to the first dart drive circuit 13a, and via the second delayed dart circuit 38 to the second dart drive circuit 13b.

FIG. 4 is a waveform diagram for explaining the operation of the circuit shown in FIG. 3. The operation of the signal sending circuit shown in FIG. 3 will be explained below based on FIGS. 3 and 4.

When sending a paging signal to a subscriber terminal, the control circuit 14
Then, a control signal T15T2 having a timing as shown in FIG. 4(4) is applied to the exclusive operation circuit 13. When the control signal T1 is ON and the control signal T2 is OFF, the first dart drive circuit 13a operates and the second dart drive circuit 13b operates.
doesn't work. Accordingly, the semiconductor switch 1 is closed, the semiconductor switch 12 is opened, and the ringing signal is transmitted from the ringing signal source 5 as follows: Subscriber line 2 -> line 8 -> resistor R2 -> negative power supply 7 ->earth's roots, subscriber terminal 1 is called 0 Next, there is a ringing signal pause period, that is, the sending of a signal from the ringing signal source 5 During the period in which the - ground signal is sent to the subscriber terminal 1, the control signal T1 is OFF and the control signal T2 is ON.Therefore, the semiconductor switch 12 is closed, and the semiconductor switch 11 is closed. is released.In this way, the control signal T
! .

At 08 o'clock, the semiconductor switch 11 outputs the control signal T2 at 08 o'clock.
At times, each of the semiconductor switches 12 becomes conductive, and repeated signals such as a calling signal and a local signal as shown in FIG. 4(B) are sent to the subscriber terminal 1.

At this time, since the semiconductor switches 11 and 12 are composed of semiconductor devices having a current self-holding function such as a pnpn) runnostar, as shown as 0 point in Fig. 4 ω),
Control signal T1 goes from ON to OFF, control signal T2 goes OFF
Even when switching from F to ON, the current flowing through the semiconductor switch 11 may not immediately become zero due to the current self-holding function.

In this case, the detection circuit 13c in the exclusive operation circuit 13 detects that the semiconductor switch 1 is still in the closed state, and as shown in FIG.
The semiconductor switch 12 is not driven until the current self-holding function of the semiconductor switch 12 is released and the semiconductor switch 12 is in an open state.

Therefore, the collision between the two signals that occurs when two signals are sent out by repeating alternate closing and opening using a semiconductor element with a current self-holding function does not occur◇ Fig. 5 3 is a circuit diagram showing the circuit shown in FIG. 3 in more detail.

The operation of this circuit will be explained.

A control signal is sent from the control terminal 20, and the first dirt drive circuit 13af is driven via the first delay gate circuit 2 so that the first dart drive circuit 13m operates and the second dirt drive circuit 13b does not operate. , pnpn) via the drive terminal 22 and diode 23, pnpn) via the N gate of transistor Ila or diode 24, pnpn) via the N gate of lannostar Ilb or drive terminal 25 and diode 26, pnpn) When the P gate of the transistor 11b (pnpn) is driven through the P gate or diode 27f, the paging signal source 5 outputs a paging signal to the output terminal 28. p like this
When npn) Rannostar lla or pnpn) transistor Ilb is conductive, pnpn) Each dart of transistors 11 &, Ilb and the transistor connected to it constitute a current mirror circuit, so pnpn
When the pn transistor Ila is conducting, the current is PNP) Collector of Lannostar 29 → Diode 30
-> current addition circuit 3 or current addition circuit 31 -> diode 32 -> NPN) Flows with the collector of the runno star 33.

'tft, pnpn) Current is PNP even when Lanzo star llb is conductive.) Run raster 34 → diode 3 → current addition circuit 31 or current addition circuit 31 → diode 36ONPN) Collector of Lanzo star 32 and flow, current addition circuit 3 The output information indicating that the semiconductor switch 11 is conducting is outputted from the node 38, and becomes operation prohibition information for the second gate drive circuit 13b via the second delay dart circuit 38.

Next, a control signal is sent from the control terminal 20 to the second date drive circuit 13b via the second gate delay circuit 38 so that the first dart drive circuit 13m does not operate and the second dart drive circuit 13b operates. When driven, the P gate of the pnpn) runnoster 12b is driven via the drive terminal 39 and the diode 40, or the P gate of the pnpn) runnoster 12a is driven via the diode 4.

In this way, pnpn) transistor 12b or pnp
n) When the transistor 12m is conductive, the pnpn transistors 12a and 12b constitute a current mirror circuit, so when the transistor 12m is conductive, the current is delayed by the first delay. Dirt circuit 21→diode 42→NPN) flows to the collector of transistor 43. In addition, when the pnpn) transistor 12m is conductive, the current flows from the first delay dart circuit 21 → diode 44 → NPN) rannostar 4
5 collector and the flow prohibits the operation of the first dart drive circuit 13a.

Now, consider a case where the semiconductor switch 11 is to be changed from a conductive state to a non-conductive state, and the semiconductor switch 12 is to be changed from a non-conductive state to a conductive state. When the above-mentioned control signal is applied to the control terminal 20, each current mirror of the semiconductor switch 1 via the current addition circuit 31f is turned off by the second delay dart circuit 38 together with the control terminal information. A drive current is outputted to the second dart drive circuit 13b with a delay time larger than the drive terminal 39.
The semiconductor switch 12 is driven via 46.

On the other hand, consider the case where the semiconductor switch 1 is to be changed from a non-conducting state to a conducting state, and the semiconductor switch 12 is to be changed from a conducting state to a non-conducting state. When the control signal as described above is applied to the control terminal 20, each current mirror of the semiconductor switch 12 via the diode 42 or the diode 44 is transferred to the first delay dart circuit 2 along with the control terminal information. A drive current is output to the first dirt drive circuit 13a with a delay time longer than the turn-off time, and the semiconductor switch 1 is driven via the drive terminal 22 and the drive terminal 25.

Furthermore, when the semiconductor switch 12 attempts to become non-conductive,
The output from the drive terminal 46 is connected to N via a diode 47.
pn) by driving the base of transistor 48
pnpn) Clamp between the dirt and cathode of transistor 12b, or connect NPN via diode 49.
By driving the base of the Darlington transistor 50, the dart of the pnpn) transistor 12& and the cathode of the diode 51 are clamped, forcing the pnpn
) The anode current is actively cut off by drawing current from the P gate of the transistor 12a.

In this way, in this embodiment, the conduction/non-conduction of the pnpn (pnpn) transistor constituting the semiconductor switch is detected and used as one of the control information, which is input to the control circuit, and with a delay longer than the turn-off time of the semiconductor switch. By transmitting the control signal through a delay circuit that gives I can do it.

As described above in detail, according to the present invention, when sending out a calling signal through a semiconductor switch having a current self-holding function, control is performed so that the sent signals do not collide with each other. Therefore, it is possible to realize a stable calling signal sending method that does not destroy the switch and can also prevent malfunctions caused by residual charge in the circuit that would occur when a switch with a transfer contact is used.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of a conventional paging signal sending circuit, Fig. 2 is a waveform diagram showing a state of sending a paging signal to a subscriber terminal, and Fig. 3 is a circuit diagram showing an example of a conventional paging signal sending circuit. The circuit diagram of the applied current sending circuit, Fig. 4 (4), (B) is a waveform diagram for explaining the operation of the circuit of Fig. 3, and Fig. 5 is a waveform diagram for explaining the operation of the circuit of Fig. 3.
FIG. 2 is a detailed circuit diagram of the circuit shown in FIG. ■...Subscriber terminal, 2...Subscriber line, 5...Call signal source, 11.12...Semiconductor switch, 13.
・・Exclusive operation circuit. Patent Applicant Oki Electric Industry Co., Ltd. Nippon Telegraph and Telephone Public Corporation NEC Corporation Hitachi, Ltd. Page 1 continued 0 Inventor Shinji Okuhara Inside the Totsuka Factory of Hitachi, Ltd., 216 Totsuka-cho, Totsuka-ku, Yokohama City Haruyuki Yoshino, 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Fujitsu Ltd. Applicant: Nippon Telegraph and Telephone Public Corporation ■ Applicant: NEC Corporation, 5-33-1 Shiba, Minato-ku, Tokyo ■ Applicant: Hitachi, Ltd. Tokyo No. 5-1, Marunouchi-chome, Chiyoda-ku, Tokyo ■Applicant: Fujitsu Ltd. 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi Procedural Amendment (ML Ship 7310 Showa year, month, day, Japan Patent Office Commissioner) Indication of the case 1950 No. 205074 3 Relationship with the case of the person making the amendment Patent application office (
Address: 105) 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Representative of Oki Electric Works S Co., Ltd.
Director and President Masao Miyake 4 Agents
(4 others) Location (105) 1-7 Toranomon, Minato-ku, Tokyo
No. 2 Guan Shochu ``纂S 狪'' and ``Fig. 4'' Contents of the correction (m paper 0, etc.) 6. Contents of the correction (1) Corrected as ``leakage including f circuit''. (2) In the same book, page 14, line 2 of the irises, the words ``hereinafter'' have been amended to read ``other than.'' (3) On page 5, line 6 of the same book, "13b and" is replaced with "13b, the detection circuit 15, the first delay r-) times 1@21, the M2 delay dart circuit J8 and the control circuit 14". to correct. (4) On page 1116, line 6 of the same book, "Subscriber terminal 1" is corrected to "Subscriber terminal 1."cs> On page 6 of the Girt book, lines 12 to 14, the phrase ``Semiconductor switch 12 is closed, and semiconductor switch 11 is opened...'' has been replaced with ``Semiconductor switch 11 is one clause,
The semiconductor switch 11 is closed.'' is corrected. (4I) In the 8th line of page 7 of the same book, "Circuit 1s." is corrected to "Circuit 1j@." (7) In line 10 of page 7 of the same collection, the phrase ``state of indifference'' was replaced with ``
The open state after the turn-off time has elapsed. (8) Correct drawing Figure 3 with the attached sheet. (9) Drawing #! Revise Figure 4 from the attached sheet. that's all

Claims (1)

[Claims] When the calling signal and the ground signal are alternately sent to the subscriber line via the current self-holding semiconductor switch, after the sending of the calling signal is completed and the turn-off time of the current self-holding semiconductor switch has elapsed. A method for transmitting a calling signal, characterized by transmitting the geosignal.