JPS6033794A - Trunk line circuit system - Google Patents

Abstract

PURPOSE:To realize the channel switching function and the signal transmitting function of a trunk line with one changeover circuit by providing a common transmission circuit to transmit a holding tone and a PB dial signal in a trunk line changeover circuit required for the transmission of a dial impulse. CONSTITUTION:Relays DI, DS are not activated during talking or before hooking off and a holding tone gate MHG and a PB dial signal gate PBG are closed, then contacts di, ds are contacted and a telephone set is connected to the trunk line. The relay DS is activated and its contact ds is connected to impedance Rh, and the relay DI repeats operation and restoration by the pulse number based on the dial information, then the contact di intermits a DC circuit and a prescribed impulse is transmitted at the transmission of the impulse. The relay DS is activated at holding or PB dialing, the holding tone gate MHG or the PB dial signal gate PBG is opened, and the holding tone or the PB dial signal is transmitted through the amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention provides a method for transmitting dial impulses, PB dial signals, and hold tone to a central office line by using a main device to transmit dial impulses to a central office line, a PB dial signal, and a holding tone. This relates to the circuit system.

(Conventional method) Conventionally, the main device has a dial impulse sending circuit, PB
A dial signal No. 3 sending circuit and a holding tone sending circuit are set up, and the above circuits are driven by information from the telephone to dial-in.
or system or PB dial signal '7) The so-called electronic type that sends out and holds music from the main device side? Tan telephone equipment has been put into practical use.

FIG. 1 is a circuit diagram showing a conventional example of a central office line circuit in such a telephone device.

First, a conventional example shown in FIG. 1 will be explained.

In Figure 1, L, , L are the central office lines, and DI is the relay coil that sends dial-in ie system to the central office line.
i is the contact point, DS is the relay coil that switches the call path when sending a dial impulse to the office line or PB dial signal, d8 is the contact point, and ■ is the relay coil that switches the call path to hold the office line. In the coil of the relay that performs h
is the contact point, K is the dial system setting switch that selects and sets the format of the dial signal sent to the central office line as either dial impulse or PB dial signal, and PBO and PBA are the PBs that are required based on the dial information from the telephone.
PB dial signal generation circuit that sends dial signals and its amplifier circuit, PBG is a dirt circuit, MHO and MHA
is a hold sound source circuit and its amplifier circuit, PT is a transformer that separates the office line and amplifier circuit PBA for sending out PB dial signals in direct current and combines them in alternating current, and HT is an amplifier circuit MHA for sending out held music and the office line. ATT is an attenuation circuit that reduces crosstalk between each office line when holding music is sent to multiple office lines at the same time. It attenuates the PB dial signal and sends it to the telephone, and also transmits the outgoing call signal from the telephone (
Rh is a resistor that reduces the mixing of voice (voice) into the pn dial signal, Rh is a resistor that performs direct current termination of the central office line and maintains an open call loop when the central office line is on hold, and CPU is a control circuit mainly based on a microprocessor. be. If the dial signal system of the central office line is the system dial system, set the dial system setting switch K to the side shown in the figure.

The transmission of the dial pulse is performed by operating the relay DS under the control of the control circuit CPU, and then repeating the recovery of the telephone at the set speed and make rate by the relay DI.
After sending out the dial-in system in this way, the relay DS is restored.

If the dialing signal system of the central office line is the PB dialing system,
Switch the dial system setting switch K to the opposite side from that shown.

To send out the PB dial signal, the control circuit CPU first operates the relay DS, and then the PB dial signal generation circuit PBO generates the PB dial signal corresponding to the dial information from the telephone under the control of the control circuit CPU. The corresponding P is generated by the amplifier circuit PBA for sending out the PB dial.
The B dial signal is amplified to an appropriate level and sent to the office line via the coupling transformer PT, the dial system setting switch K, and the contact ds. At the same time, the PB dial signal is supplied to the telephone as a dial-back tone through resistor nb.

When the transmission of the PB dial signal is completed, the control circuit CPU restores the relay DS.

The control circuit CPU operates the relay H and terminates the office line with the DC termination resistor Rh, while amplifying the hold music from the iso-retained sound source circuit MHO to an appropriate level with the hold-music amplifier circuit, and connects it to the coupling transformer. HT is applied to both ends of the DC termination resistor Rh via the attenuation circuit ATT and sent to the central office line.

(Disadvantages of the conventional method) According to the conventional method described above, two relays (DS and H) are required for the communication path changeover switch per one office line, and one for sending the PB dial signal and one for sending the hold tone. Each requires a coupling transformer, output amplifier circuit, etc. or,
The held sound source circuit is connected to multiple office line circuits in duplicate, and since office line holding may be performed simultaneously on multiple office line circuits, an attenuation circuit is inserted in the held sound transmission path to reduce crosstalk between office lines. It is not only economically disadvantageous to use a large number of circuit elements, but also makes it difficult to miniaturize the device.

(Objective of the present invention) The present invention has been made to solve the above-mentioned problems of the conventional art. The purpose of this invention is to provide a station line circuit system that does not require an attenuator. In order to achieve this objective, the present invention focuses on the fact that dial impulses or PB dial signals and hold music to be sent to the central office line are not required at the same time. In addition, a signal sending circuit is provided, and the hold tone and PB dial signals are input to the same sending amplifier circuit, and the output thereof is supplied to the signal sending circuit, thereby simplifying the circuit configuration.

(Explanation of Examples) Hereinafter, the present invention will be explained in detail with reference to FIG.

FIG. 2 shows the central line circuit section of a so-called button telephone device, and for the purpose of explaining the operation, a communication path switch, a telephone, etc. are not shown. Further, the present invention can be implemented in any type of key telephone device.

In Fig. 2, s Ll r ”+1 is the central line, D
I is the relay coil that sends dial impulses to the office line, di is its contact, and DS operates when sending out dial impulses, PB dial signals, and hold music, and connects the office line from the telephone to the signal sending circuit. ds is the contact of the coil of the switching relay, ■( is the dial system setting switch that changes the dial signal system of the station line circuit depending on the difference in the dial signal system of the station line, Rh is the station line pending,
Rh is a resistor that performs DC termination of the central office line L1゜Lz and maintains the call loop closed, and Rh is a resistor that attenuates and sends the PB dial signal to the telephone when the dial signal system is the PB dial signal system. MHO is the hold sound source circuit, PBOFiP B dial signal generation circuit,
AMP is a sending amplifier that amplifies the signals from the hold sound source circuit M)to and the PB dial signal generation circuit pno to an appropriate level, and MHG is a hold sound that inputs the signal (hold sound) from the hold sound source circuit MHO to the send amplifier AMP. Dart, PB
G is the signal from the PB dial signal generation circuit PBO (PB
LT is a coupling transformer for amplifying the dial signal) to a suitable level by the sending amplifier AMP, and CPU is a control circuit mainly based on a microprocessor.

Resistor Rh is an impedance for maintaining the communication loop (DC loop) of the office line closed when the office line is on hold.
A break contact (di) is inserted and connected in series with the resistor Rh in the call loop, and further in the call loop is a contact of a relay DS which is a switch means for switching the office line to the resistor Rh side or the telephone side. d8 is connected. In the embodiment, the contact di is inserted into one side of the communication line, but it may be inserted anywhere within the communication line.

An alternating current signal application means, a coupling transformer LT, and a sending amplifier AMP are arranged in series in this order and connected to both ends of the resistor Rh, and a PB dial signal gate (first dirt circuit) is connected to the input of the sending amplifier AMP. PBG and PB
Dialing signal generation circuit PBO (cascade configuration and hold tone generator) MHG and hold tone source circuit Also, at both ends of the break side of the contact ds, there is a resistor Rh that attenuates the PB dial signal and sends it to the telephone as a dial pack tone to set the dialing method. It is connected via a switch K, and when the dial signal method is the pulse dial method, the corresponding dial method setting switch K is opened, and when the dial signal method is the PR dial method, the corresponding dial method setting switch K is closed. Make it.

PB dial signal generation circuit PBO and hold sound source circuit MH
The output of O is the PB dial 48 of each other station line circuit.
Dual connection is made to the number and hold music dart. That is, P
B-dial signal generation circuit PBO and hold sound source circuit (0 is shared by multiple office line circuits.

What about the hold sound source circuit MHO and hold sound dirt MHG? This is necessary only when the tongue telephone device is provided with a hold tone sending function, and is not related to the basic functions of the office line circuit.

Next, the operation will be explained.

(1) Normal state (state before making a call to the central office line and during a call to the central office line)
Under normal conditions, relay D1. IJ Ray DS are not working together. In addition, the hold tone r-) MHG, PB dial signal, and p-to PBG are also closed. In this state, if you capture the office line circuit from the telephone, the telephone and the offices alL+, L
A communication path with x is formed using the following route. Office line L1 - contact di 'dj handset - contact d8 - office line line L2 (2) Operation when sending dial impulses (if the dial signal system of the office line is pulse dial system) Set the dial system as described above. Open to switch. When dialing from a telephone, the control circuit CPU first sends a message to relay DS.
is operated, and then the relay DI for dial-in/e-system transmission is controlled to repeat operation and recovery as many times as the number of e-systems based on the dial information from the telephone at the set speed reduction rate. In other words, when the relay DI is restored, "office line Ll - contact di (relay DI
is restored) - Resistor Rh - Contact ds (Relay DS operates) -
A DC circuit is formed for the office line at the route of the office line L2J, and when the relay DI is operated, the contact di in the route is opened, so the DC circuit is disconnected. In this way, a predetermined dial impulse is sent to the central office line by intermittent operation of the DC circuit.

Further, at this time, the communication path between the telephone and the office line is cut off by the contact d8, so that the so-called click sound of the dial impulse does not enter the telephone.

When the transmission of the predetermined dial impulse is completed, the desk control device CPU restores the relay DS, and the office line circuit returns to the normal state.

(3) Operation when transmitting a PB dial signal (when the dial signal system of the central office line is the PB dial system) For the central office line that transmits the PB dial signal, the dial system setting switch is closed as described above. ing.

When dialing with a telephone, the control circuit CPU first operates the relay DS, then causes the PR dial signal generation circuit PBO to generate the necessary PB dial signal based on the dial information from the telephone, and generates the PB dial signal G. )
Open the PBG and input the PB dial signal to the sending amplifier AMP.

The signal is amplified and sent to the PB via a coupling transformer LT.
The dial signal is sent to the central office line by applying it to both ends of the resistor Rh. At this time, the DC terminal of the office line is formed by a resistor Rh, and the DC loop of the office line during transmission of the PB dial signal is maintained by the resistor Rh.

In addition, the PB dial signal sent to the office line has a damping resistance R
It is attenuated by h and sent to the telephone at the same time, and a so-called confirmation tone (back tone) of the PB dial signal is sent to the telephone.

When the transmission of the PB dial signal is finished, the control circuit CPU controls the relay DS to recover, and the PB dial signal (G) is output.
BG is also closed and the state returns to normal.

As mentioned above, the PB dial signal generating circuit PBO is shared by multiple office lines, and the PB dial signal generating circuit PBO and PB dial signal generating circuit PBO of each office line circuit are connected to each other.
By time-division control of BG, even if a call is made to multiple office lines at the same time, a separate PB dial signal is sent to each side of the multiple office lines. (4) Operating station line when the office line is held When the central office line is put on hold with the telephone during a call, the control circuit CPU operates the relay DS and connects a resistor Rh between the central office lines L, L2 through its contact d8 to maintain a DC loop for the central office line. Remove your phone from the central office line! ,
Release rI to complete the station line hold state.

When the station line circuit is provided with a holding tone sending function, the control circuit CPU operates the relay DS and also controls the opening of the held tone Ml-IG to transmit the held tone source circuit-0. The hold tone being generated is input to the sending amplifier AMP via the holding tone dirt MHG, and in the same manner as the sending operation of the PB dial signal, the hold tone is applied to both ends of the resistor Rh and sent to the central office line. do.

In a device accommodating multiple office lines, each office line circuit is provided with ■1G in the hold tone dart, so that -1
Hold tone can be supplied from two hold tone source circuits.

In addition, when multiple office lines are on hold at the same time and hold music is sent to the multiple office lines at the same time, the output signal (hold music) from the hold sound source circuit MHO is transmitted to the output amplifier f AMP of each office line circuit. Since the distribution is done on the input side, the audio on a specific station line will not mix with other station lines via the hold music transmission path. That is, there is no crosstalk between multiple office lines.

As explained in detail above, the present invention includes dial-in A system sending means in the holding loop of the central office line, holding tone and PB.
This is achieved by providing a common transmission circuit for transmitting dial signals, which unifies the signal transmission route, simplifies the equal circuit configuration that can be configured with a small number of control relays, and makes it more economical. The present invention has an extremely large effect, since the device can be made smaller.

Further, in the embodiment, a relay contact is used as the dial innoxis sending means, but semiconductor switching means such as a transistor or a photocoupler may also be used as the inno or sys sending means.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. IJ1+L2...Station ρ line DI...Guyalinno? System sending relay DS...
・Relay for switching back (...Dial system setting switch MHO...Holding sound source circuit PBO...pn dial signal generation circuit MHG...Holding sound dirt PBG...PB dial signal GUT

Claims (1)

[Claims] 1. An impedance for maintaining the communication loop closed to the office line side, an impulse sending means inserted in series with the impedance in the communication loop closing path, A station line circuit system having a switch means for selectively connecting a line to either a telephone or the impedance, and switching the switch means to the impedance side when sending an impulse or when the station line is on hold. 2. An impedance for maintaining the communication loop closed with respect to the office line side, an impulse sending means inserted in series with the impedance in the opening path of the communication loop, and an impedance for connecting the office line to the telephone or the impedance. A switch means for switching connection to either one, a hold sound source, and a dart circuit for applying the output of the hold sound source to both ends of the impedance, the switch means is switched to the impedance side, and the dart circuit is opened when the central line is held. A station line circuit system in which a hold tone is applied to both ends of the above impedance. 3. An impedance for maintaining the communication loop closed to the central office line side, a switch means for selectively connecting the central office line to the telephone or any of the above impedances, a PB dial signal generation circuit, and the pn dial signal. It has a dart circuit that applies the output of the generating circuit to both ends of the impedance, and switches the switch means to the impedance side when transmitting the PB dial signal and when the central office line is on hold.
A central office line circuit system in which a PB dial signal is applied to both ends of the impedance by opening the dirt circuit when transmitting a B dial signal. 4. An impedance for maintaining the call loop closed to the central office line side, a switch means for selectively connecting the central office line to the telephone or any of the above impedances, a PB dial signal generating circuit, and a holding impedance for the above impedance. It has a first dart circuit that applies the output of the hold sound source to both ends of the impedance, and a second dart circuit that applies the output of the hold sound source to both ends of the impedance. and P
A central office line circuit system in which the first dart circuit is opened when a B dial signal is sent out, and the second dart circuit is opened when the central office line is on hold, thereby applying a PB dial signal or a holding tone to both ends of the impedance.