JPS62188540A - Ringing sending system - Google Patents

Abstract

PURPOSE:To protect an equipment connected to a communication line from a fault by the faulty voltage of a contacted power supply by sending a ringing to a line after the absence of contact of a commercial power line is recognized by a detection means. CONSTITUTION:When a call comes to a telephone set 1, the relay contact (t) of a TST 30 is operated in an LC 3 to draw a subscriber line 2 to a DET 33. If an AC 4 contacts the subscriber line 2, the DET 33 detects it to send a detection signal to a FF 34. The inverse of Q output of the FF 34 drives a transistor 35 to reset forcibly an R relay during the operation, then even when the relay contact (t) is restored by attending with the end of test, no ringing is fed to the subscriber line 2 from an RGG 36. Thus, the subscriber line 2 is tested and the absence of contact of the AC 4 is confirmed, then ringing is sent to protect the RGG 36 from an abnormal voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ringing transmission system, and more particularly to a ringing transmission system that prevents ringing from being transmitted to a communication line that is in contact with a commercial power line.

1] Prior art] Conventionally, there was no circuit to protect communication lines from commercial power line contact when it occurred.6 [Problems to be solved by the invention] In the conventional ringing transmission method described above, commercial power line Since ringing is also transmitted to the communication line that is in contact with the communication line, there is a drawback that a failure may occur in the communication equipment connected to this communication line.

[Means for solving problems]

The ringing transmission method of the present invention includes a detection means for detecting whether or not a commercial power line is in contact with a line, and a ringing transmission system that transmits ringing to the line after confirming that there is no interference in the commercial power line by the detection means. equipped with the means.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit block diagram showing one embodiment of the ringing transmission method of the present invention, showing an example applied to a subscriber circuit of a time division exchange, and FIG. 2 is an example of the commercial power cross contact detection circuit in FIG. 1. FIG.

In Figure 1, the subscriber circuit (hereinafter referred to as LC) of the time division exchange
) 3 is connected to the telephone set 1 by the subscriber line 2, and shows a state where the commercial power supply (hereinafter AC>4) is in contact with the subscriber line 2.LC3 is the test circuit (hereinafter T) connected to the subscriber line 2.
ST) 30. Ringing sending circuit (hereinafter referred to as RGS) 31.
While the call current supply circuit (hereinafter referred to as 5UP) 32 and the relay contact t of the TST 30 are operating, the subscriber line 2 is connected to the AC
A commercial power supply contact detection circuit (hereinafter referred to as DET) 33 detects the presence or absence of contact with AC4, and a transistor 35 that resets the R relay of RGS31 by the inverted output Q of a flip-flop (hereinafter referred to as FF) 34 when DET33 detects contact with AC4. and a ringing generator (hereinafter referred to as RGG) 36 that sends ringing to the subscriber line 2 via the relay contact r when the R relay operates. DET33 is connected to TST30 by diode bridge 5 as shown in FIG.
When the AC 4 is detected to be connected to the subscriber line 2 via the subscriber line 2, the photocoupler 6 sends a detection signal to the FF 34.

Next, the operation of this embodiment will be explained.

phone#! When the call arrives at &1, LC3 sends T S T30
Activate the relay contact t (shown by the broken line) to connect the subscriber line 2.
is drawn into DET33. When the AC 4 is in contact with the subscriber line 2, the DET 33 detects this and sends a detection signal to the FF 34. Since the FF 34 drives the transistor 35 with the inverted output Q and forcibly resets the R relay that was in operation, ringing from the RGG 36 will not be added even if the relay contact t is restored by means not shown at the end of the test. The data is not sent to the user line 2.

Also, when subscriber line 2 is connected to DET33, AC
4 is not detected, the DET 33 does not send out a detection signal, so the R relay continues to operate, and the relay contact r is in the state shown by the broken line. Therefore, when the relay contact t is restored, the ringing from the RGG 36 is sent to the subscriber line 2 via the relay contact r (shown with a broken line) and the relay contact t (shown with a solid line), and the telephone set 1 is called. telephone 1
When the telephone 1 responds, the telephone 1 is supplied with talking current from the 5UP 32, as is generally known.

That is, in this embodiment, the ringing is transmitted only when the subscriber line 2 is tested and it is confirmed that there is no interference with the AC 4, so the RGG 36 can be protected from abnormal voltage.

Although the present embodiment has been described with respect to a subscriber circuit of a time division exchange, it goes without saying that the present invention can be applied to communication equipment having a ringing transmission function such as an l-rank circuit.

〔Effect of the invention〕

As explained above, the present invention protects devices connected to the communication line from failures due to abnormal voltages of the interfering power supply by testing the communication line and confirming that there is no interference between the applicable power supply lines and then transmitting ringing. There is an effect that can be done.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of the ringing sending system of the present invention, and FIG. 2 is a circuit diagram showing an example of the commercial power source cross contact detection circuit in FIG. DESCRIPTION OF SYMBOLS 1... Telephone, 2... Subscriber line, 3... Subscriber circuit (LC), 4... Commercial power supply (AC), 5... Diode bridge, 6... Photocoupler, 30... ...Test circuit (TST>, 31...Ringing sending circuit (R
GS), 32...Speech current supply circuit, (SUP), 3
3...Commercial power supply cross contact detection circuit (DBT), 34...
- Flip-flop (FF), 35...transistor, 36...ringing generator (RGG).

Claims (1)

[Claims] It is characterized by comprising a detecting means for detecting whether or not a commercial power line is in contact with the line, and a ringing sending means for sending ringing to the line after confirming that there is no contact with the commercial power line by the detecting means. Ringing transmission method.