JPH0316821B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit for transmitting ringing of a subscriber interface circuit in a time division telephone exchange.

With the spread of time-division telephone exchanges in recent years, subscriber interface circuits are being computerized, with a focus on the basic function called BORSHT. B is
Battery feed, O is Over voltage protection,
R is Ringing, S is Supervision, H is Hybrid,
T stands for Test, and these functions alone could not deal with the large AC induced noise superimposed on the subscriber line connected to the subscriber interface circuit. Therefore, a noise cancellation coil (NSC) is inserted into the subscriber line to remove the above noise. However, the insertion of this noise removal coil increases the impedance on the subscriber side, which has the disadvantage that if the subscriber terminal is a multi-party line, the ringing of the bell will be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit that can send out ringing to a subscriber line into which a noise removal coil is inserted, which can cause the subscriber terminal to ring at a normal volume even when the subscriber terminal is a multi-party line. .

In order to achieve the above object, the ringing transmission circuit using sleeve wire control according to the present invention connects a sleeve wire equipped with a relay contact for the sleeve wire in parallel to a subscriber line into which a noise reduction coil is inserted, and when transmitting ringing, The ringing circuit is connected to the subscriber line by a ringing transmission relay, and the sleeve wire relay contact is closed to short-circuit the noise removal coil, and after the ringing transmission is completed, the sleeve wire relay contact is opened. It has been done. According to the above configuration, the ringing tone of the bell of the multiparty line can be maintained normally without deteriorating the quality during a call, and the object of the present invention is completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings. The figure is a circuit diagram showing an embodiment of a ringing sending circuit according to the present invention. The ringing sending circuit according to the present invention includes a noise removal circuit section, a subscriber interface circuit section, a control section, and a ringer section.
Consists of RINGER. In addition, POW
is the power supply circuit section. Subscriber terminals A, B... are a multiparty line, and each subscriber line L ₀
~L ₃ has a noise removal coil NSC inserted. Furthermore, sleeve wires S ₀ -S ₃ are connected to correspond to each subscriber line L ₀ -L ₃ , respectively. In the noise removal circuit section, TERM0 and TERM of sleeve wire _S0
Each terminal of 1 is a noise removal coil for subscriber line L ₀ .
It is connected to each terminal of TERM2 and TERM3 on the subscriber terminal side of the NSC. Similarly, terminals TERM4 and TERM5 of sleeve wire _S1 are also connected to the subscriber terminal side of the noise removal coil NSC of subscriber line _L1 .
It is connected to each terminal of TERM6 and TERM7, respectively, and such connections are made to all subscriber lines. A shorting fitting is used to connect between the TERM terminals. In the subscriber interface circuit section, a relay contact rs for ringing transmission is inserted into the subscriber line, and in addition to this, a relay contact sl for controlling the sleeve wire is connected to the sleeve wire, and one end of the contact sl is connected to the contact rs. It is connected to the noise removal circuit side of the subscriber line where the is inserted.
With the above configuration, a short circuit line is formed in parallel to the noise removal coil NSC via the sleeve wire. The sleeve wire relay SL and the ringing sending relay RS are controlled by the control section.

Next, the operation of the ringing sending circuit will be explained using a case where subscriber terminal (hereinafter referred to as subscriber) A makes a call to subscriber B as an example.

When subscriber A goes off-hook, the software calls subscriber A's outgoing call, sends a dial tone to subscriber A, and waits to receive a dial number from subscriber A. After receiving the dialed number, it analyzes the numbers and prepares to send a ringing call to subscriber B. Then, by controlling the addresses A0 to A3 of the control unit of the subscriber interface circuit unit,
side relay RS ₀ , SL ₀ , subscriber B side relay RS ₂ ,
Activate SL ₁ and connect its contacts sl ₀₀ , sl ₀₁ , rs ₀₀ ,
Close rs ₀₁ , sl ₁₀ , sl ₁₁ , rs ₂₀ , rs ₂₁ . Therefore, RBT (Ring back tone) is sent to subscriber A, and RGT is sent to subscriber B. Since the noise removal coil of RGT is short-circuited, there is no attenuation and subscriber B's bell rings normally. When subscriber B responds, a ring trip occurs and the relay on subscriber A side
RS ₀ , SL ₀ , relays RS ₂ , SL ₁ on subscriber B side are restored, and their contacts rs ₀₀ , rs ₀₁ , sl ₀₀ , sl ₀₁ , rs ₂₀ , rs ₂₁ ,
sl ₁ is opened, ringing transmission is stopped, and subscriber A and subscriber B are in a talking state. In the call state, the relay is restored, so the call route passes through the noise reduction coil, thereby maintaining the call quality between subscribers A and B.

As described above in detail, the ringing sending circuit according to the present invention activates relays SL ₀ and SL ₁ by sleeve wire control while sending ringing,
The configuration is such that the noise-cancelling coil NSC is short-circuited, and when a call is made, relays SL ₀ and SL ₁ are restored and the noise-cancelling coil is inserted into the call path, so that normal bell ringing is supplied to the subscriber terminal and the call is terminated. It can provide a high quality communication path.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of a ringing sending circuit using sleeve control according to the present invention. NSC...Noise removal coil, A, B...Subscriber terminal, RS, SL...Relay, rs, sl...Relay contact,
POW...Power circuit, RINGING...Ring tone.

Claims (1)

[Claims] 1. A sleeve wire equipped with a sleeve wire relay contact is connected in parallel to the subscriber line into which the noise elimination coil is inserted, and when sending out ringing, the ringing circuit is connected to the subscriber line by the ringing sending relay, and the above-mentioned A ringing sending circuit using sleeve wire control, characterized in that the sleeve wire relay contact is closed to short-circuit the noise removal coil, and the sleeve wire relay contact is opened after ringing sending is completed.