JP2002077962A - In-band ringer for achieving pbx dial-in - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-band ringer for achieving dial-in connection to a telephone being accommodated in a PBX using an exclusive line from a switchboard. SOLUTION: This in-band ringer is composed by connecting the switchboard 9 having an OD trunk, a PBX 10 having a CO trunk, an in-band ringer 11 for OD trunks for inputting and outputting by converting a controls to a plurality of control signals composed by an in-band frequency, or by converting the plurality of control signals composed by an in-band frequency to the control signal, an in-band ringer 12 for CO trunks for inputting or outputting by converting the control signal to the plurality of control signal composed by an in-band frequency, or by converting the plurality of control signals composed by an in-band frequency to the control signal while the in-band ringer 12 has the polarity inversion section of a DC application voltage, and a plurality of telephones 13a, 13b, and 13c accommodated in the PBX 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-band ringer capable of PBX dial-in, and in which an in-band ringer is installed in a dedicated line section constituting a transmission line to perform dial-in connection between an exchange and a PBX. The inband ringer that enabled

[0002]

2. Description of the Related Art Conventionally, as a means for constructing a network connecting offices, a PBX of each office or a telephone terminal represented by a telephone is provided by a dedicated line or a private line provided by a telecommunications carrier. It is widely used because it is possible to realize a toll dial or extension of an extension and to realize an economical network. A dedicated line or a private line provided by a communication carrier used when constructing such a network often defines a frequency band that can be used by a user, and receives a dedicated line service for the above-described purpose. In this case, the voice band frequency is generally 0.3 kHz.
The band is limited to z to 3.4 kHz. Therefore, when constructing a network using such a dedicated line,
It is not possible to transmit a low frequency or DC signal such as a necessary dial pulse signal, a ringing signal of 16 Hz, a switching signal of a DC circuit, etc. between the PBX and the PBX or between the PBX and the telephone. Transmitting the signal. The in-band ringer converts a low-frequency or direct-current signal necessary for controlling the PBX and the telephone into a voice band frequency that can be transmitted to a dedicated line, and transmits the converted signal. It also has a line loss compensation function.

FIG. 6 shows an example in which a conventional in-band ringer is used when extending an extension. An in-band ringer 2 connected to a PBX 1 and an in-band ringer 4 connected to a telephone 3 via a dedicated line. It consists of. In the present usage example, an operation when a call is received from another telephone to the telephone 3 through the PBX 1 will be described as an example.
After selecting the line in which the telephone 3 is accommodated, outputs a call signal of 16 Hz for calling the telephone with a predetermined repetition period. The in-band ringer 2 detects the ringing signal of the repetition period, and intermittently controls a specific in-band control signal composed of the voice band frequency output during standby with a predetermined repetition period. The in-band ringer 4 recognizes that a call signal has arrived by detecting intermittent control signals within a specific band, and outputs the call signal at a predetermined cycle from a 16 Hz oscillator built in the in-band ringer 4. Output to the telephone 3 and ring the bell of the telephone. Next, when the telephone 3 is off-hook to make a call, the in-band ringer 4
The off-hook of the telephone 3 is detected by the current flowing through the DC circuit on the telephone 3 side, and the in-band control signal output during standby is cut off. Therefore, inband ringers 2, 4
In both cases, the transmission of the in-band control signal is stopped, the DC circuit to the PBX 1 to which the in-band ringer 2 is connected is closed, and a transition is made to the talking state. Since the in-band ringer uses the in-band frequency as the control signal as described above, the in-band control signal is transmitted during no-call so as not to affect the call.

[0004]

In constructing a network, a communication line is reduced by connecting a public line and a dedicated line to each other, in addition to establishing a network using a dedicated line as described above. It is possible to build a network to make it possible. FIG. 7 is a configuration diagram showing an example in which a public line and a private line are interconnected. FIG. 7A shows a case where the network is composed of only a public line.
(B) shows a case in which a network in which a dedicated line is interconnected to a public line is configured. Referring to FIG.
Is constituted by the exchange 5 and the PBX 6, and connects to the telephone housed by the PBX 6 according to a predetermined procedure. On the other hand, (b) is composed of an exchange 5, a PBX 6, and in-band ringers 7, 8 installed for interconnecting a dedicated line to a public line. The in-band ringers 7, 8 are composed of the exchange 5 and the PBX 6 The control signal transmitted and received between the control signal and the control signal is converted into an in-band frequency control signal suitable for transmission on a dedicated line and relayed.

However, the conventional in-band ringer does not support a polarity reversal function and an operation sequence in accordance with a predetermined procedure when dial-in connection is made with a telephone housed in the PBX. Dial-in connection to a PBX was not possible even when interconnected and operated with a dedicated line. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the conventional in-band ringer, and enables a dial-in connection from a switch to a telephone housed in a PBX using a dedicated line. P
It is an object to provide an in-band ringer that enables BX dial-in.

[0006]

In order to achieve the above object, an in-band ringer which enables a PBX dial-in according to the present invention has the following configuration. The PB according to claim 1
An in-band ringer that enables X dial-in connects an exchange equipped with an out-band dial trunk (hereinafter referred to as an OD trunk) to an in-band ringer for an OD trunk, and includes a central office trunk (hereinafter referred to as a CO trunk). In the network system in which the PBX accommodating the telephone of the above and the in-band ringer for the CO trunk are connected, and the in-band ringer for the OD trunk and the CO in-band ringer are connected via a transmission line, the input from the OD trunk is performed. The OD trunk in-band ringer converts the control signal to be converted into a plurality of control signals consisting of frequencies within a voice band, and outputs the plurality of control signals to the CO trunk in-band ringer. Converts the signal to a DC circuit control signal and And outputs to the tank, the CO
The control signal of the DC circuit output by the trunk is converted into a plurality of control signals having a frequency in a voice band by the in-band ringer for CO trunk, and is output to the in-band ringer for OD trunk. When the ringer converts the plurality of input control signals into control signals and outputs the control signals to the OD trunk, the inversion ringer for the CO trunk has a polarity inversion section of the DC applied voltage to invert the DC applied voltage to the CO trunk. The control signal is input and output according to a predetermined operation procedure while allowing the control signal.

According to a second aspect of the present invention, there is provided an in-band ringer capable of PBX dial-in, as a two-wire communication path (hereinafter referred to as 2W) as the in-band ringer for the CO trunk.
A loop detector for detecting the opening and closing of the DC circuit at
A polarity inverting unit for inverting and reversing the polarity of the DC voltage applied to the O trunk, a call signal output unit for outputting a call signal to the CO trunk, and a plurality of voice in-band frequencies to the opposing in-band ringer. A control signal transmitting unit for outputting a control signal; a line transformer for terminating a transmission line (hereinafter, referred to as SLINE); and a reception line (hereinafter, RLINE)
And a line transformer that terminates the RLINE.
An amplifier for adjusting the level of a control signal received from a line, an equalizer for flattening the line frequency characteristics of the RLINE, and a control signal detecting unit for detecting a plurality of control signals composed of frequencies in a voice band received from the RLINE When,
A busy tone (hereinafter referred to as BT) is transmitted to the 2W, and a linback tone (hereinafter referred to as RBT) is transmitted to the transmission line.
, A control unit for controlling each unit in the apparatus, a hybrid transformer for terminating the 2W, and an echo in which a reception signal from the RLINE goes to the transmission side via the hybrid transformer. An echo canceller for eliminating components, and the SLINE
An amplifier for adjusting the output level to the RLINE, an amplifier for adjusting the reception level from the RLINE and outputting 2 W, and an equalizing filter for equalizing the line frequency characteristics of the RLINE flat and blocking a control signal frequency component. It consists of.

According to a third aspect of the present invention, there is provided an in-band ringer for enabling PBX dial-in, wherein the in-band ringer for the OD trunk detects an SS signal output from the OD trunk and an in-band frequency to the SLINE. A control signal sending unit that outputs a plurality of control signals consisting of:
A line transformer for terminating the SLINE;
E, a line transformer for adjusting a control signal level received from the RLINE, and an RLI
An equalizer for equalizing the line frequency characteristics of the NE flatly;
A control signal detecting unit for detecting a plurality of control signals having a frequency in a voice band received from the RLINE, a BT to a 4-wire receiving communication path (hereinafter referred to as 4WR) and a SLLINE;
And a busy tone transmitting unit that transmits
An SR signal generator for outputting a signal, a controller for controlling each unit in the apparatus, a line transformer for terminating a 4-wire transmission communication path (hereinafter referred to as 4WS) connected to the OD trunk, and one of 4WR. An echo canceller for canceling an echo component wrapping around to the transmission side via the path of
An amplifier for adjusting an output level to the NE;
An amplifier that adjusts the reception level from E and outputs it to 4WS, an equalization filter that equalizes the line frequency characteristics of the RLINE flat and blocks a control signal frequency component;
It is composed of a line transformer terminating 4WR.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 shows a PB according to the present invention.
FIG. 1 is a system configuration diagram showing an embodiment of an in-band ringer that enables X dial-in. The figure shows an exchange 9 with an OD trunk and a PBX 10 with a CO trunk.
And an OD trunk in-band ringer 11 that converts a control signal into a plurality of control signals having an in-band frequency or converts a plurality of control signals having an in-band frequency into a control signal and inputs / outputs the same. A control signal that converts a control signal into a plurality of control signals having an in-band frequency, or converts a plurality of control signals having an in-band frequency into a control signal and inputs / outputs the signal, and further includes a DC inversion portion of a DC applied voltage. The trunk in-band ringer 12 is connected to a plurality of telephones 13a, 13b, 13c accommodated in the PBX 10. The exchange 9 and the OD trunk in-band ringer 11 are connected by an SS signal line, an SR signal line, 4WS, and 4WR. The SS signal and the SR signal are control signals, and the 4WS and 4WR are four-wire systems. It mainly transmits call signals. On the other hand, the CO trunk in-band ringer 12 and P
The BX 10 is connected at 2 W and transmits a call signal on which a DC signal and a low-frequency control signal are superimposed.

The operation of FIG. 1 will be described. When a dial-in connection is made from the exchange 9 having an OD trunk to the telephone set 13, the OD trunk provided in the exchange 9 transmits an SS signal, which is a control signal, to the OD trunk. It is sent to the in-band ringer 11 for use as a ground signal according to a predetermined procedure. Therefore, the OD trunk in-band ringer 11 that has received the control signal transmits a plurality of control signals including in-band frequencies to the CO trunk in-band ringer 12 via a dedicated line according to a predetermined procedure. The in-band ringer 12 for the CO trunk is the in-band ringer 1 for the OD trunk.
1 receives a control signal and inputs a control signal necessary for dial-in connection to a CO trunk provided in the PBX 10. The CO trunk in-band ringer 12 is provided with a polarity inversion unit for a DC applied voltage, and inverts the polarity of the DC circuit at a predetermined timing at the time of dial-in connection. On the other hand, the CO trunk in-band ringer 12 that has received the control signal from the CO trunk transmits a control signal composed of an in-band frequency to the OD trunk in-band ringer 11 via a dedicated line in accordance with a predetermined procedure. The trunk in-band ringer 11 outputs the SR signal, which is a control signal, as an earth signal to an OD trunk provided in the exchange 9. A detailed operation sequence at the time of dial-in connection will be described later with reference to FIGS.

FIG. 2 is a block diagram showing an embodiment of an in-band ringer which enables PBX dial-in according to the present invention, and shows an in-band ringer for a CO trunk. The figure shows a loop detector 14 connected to the 2W of the CO trunk to detect whether the DC circuit on the CO trunk side is closed.
A polarity inverting unit 15 for inverting and reversing the polarity of the DC voltage applied to the CO trunk;
a call signal output unit 16 that outputs a call signal consisting of z;
A control signal transmitting unit 17 for outputting a control signal of two frequencies including a frequency in a voice band to an opposing in-band ringer;
A line transformer 18 for terminating the LINE;
A line transformer 19 for terminating RLINE, an amplifier 20 for adjusting a control signal level received from RLINE,
Equalizer 21 for equalizing line frequency characteristics of E flatly
A control signal detecting unit 22 for detecting a control signal of two frequencies including a frequency in a voice band received from RLINE;
A busy / ringback tone transmitting unit 23 for transmitting BT to W and transmitting RBT to SLINE, a control unit 24 for controlling each unit in the device, a hybrid transformer 25 for terminating 2W, and a signal received from RLINE An echo canceller 26 for canceling an echo component wrapping around to the transmission side via the hybrid transformer 25;
An amplifier 27 for adjusting the output level to the E
2 that adjusts the reception level from the output and outputs 2W
8 and an equalizing filter 29 for equalizing the line frequency characteristics of the RLINE flat and blocking the control signal frequency component.

FIG. 3 is a block diagram showing an embodiment of an in-band ringer which enables PBX dial-in according to the present invention, and shows an in-band ringer for an OD trunk. The figure shows an SS that detects an SS signal output by the OD trunk.
A signal detection unit 30; and a control signal transmission unit 31 that outputs a control signal of two frequencies including a frequency in a voice band to SLLINE.
And a line transformer 32 terminating SLINE, and RL
A line transformer 33 for terminating the INE, an amplifier 34 for adjusting a control signal level received from the RLINE,
An equalizer 35 for equalizing the line frequency characteristics of the LINE flatly, and a control signal detecting unit 36 for detecting a two-frequency control signal including a frequency in a voice band received from the RLINE.
, A busy tone transmitting unit 37 for transmitting BT to 4WR and SLLINE, and an S for outputting an SR signal to the OD trunk
An R signal generating unit 38, a control unit 39 for controlling each unit in the apparatus, a line transformer 40 for terminating 4WS, and a 4W
An echo canceller 41 for canceling an echo component circulating from R to the transmission side via any path, an amplifier 42 for adjusting an output level to SLINE, and an amplifier 43 for adjusting a reception level from RLINE and outputting to 4WR. , R
An equalizing filter 44 for equalizing the line frequency characteristics of the LINE flat and blocking a control signal frequency component;
And a line transformer 45 terminating the same.

Next, the operation for dial-in connection from the OD trunk to the CO trunk via the in-band ringers installed respectively will be described with reference to FIG. 2 and FIG.
The in-band ringer converts a control signal output from an OD trunk or a CO trunk into a control signal having a frequency in a voice band prior to a telephone call at the time of outgoing and incoming calls, and transmits the control signal to the opposing in-band ringer. At the same time, it receives a control signal consisting of a frequency within the voice band received from the in-band ringer and outputs it as a control signal to the OD trunk or CO trunk. Therefore, first, in the initial state, the in-band ringer continuously turns on the control signal for both the CO trunk and the OD trunk as a standby operation. In the in-band ringer for the CO trunk, the loop detector 14 detects the DC circuit OPEN, and the control signal transmitter 17 continuously turns on the control signal composed of the frequency in the voice band under the control of the controller 24. And In the present embodiment, the control signal is composed of two in-band frequency signals composed of two frequencies, each of which is required as a control signal (hereinafter referred to as CFS) and an auxiliary control signal (hereinafter referred to as SFS). It corresponds to the operation sequence. Therefore, as a telephone standby operation, the output of the control signal sending unit 17 is ON for both CFS and SFS. On the other hand, in the in-band ringer for the OD trunk, similarly to the in-band ringer for CO, the outputs of the control signal transmitting unit 31 are both ON in the CFS and the SFS.

Next, when dial-in connection is started from the OD trunk to the CO trunk, the in-band ringer for the OD trunk confirms that a ground signal (hereinafter referred to as GND) is output from the OD trunk as an SS signal. It is detected by the SS signal detection unit 30. Therefore, the OD trunk in-band ringer controls the control signal transmission unit 31 and outputs the CF signal.
S is turned off, SFS is turned on for 1 second, and turned off for 2 seconds. The in-band ringer for the CO trunk detects the CFS and SFS by the control signal detection unit 22, operates the polarity inversion unit 15 under the control of the control unit 24, and inverts the polarity of the DC voltage applied to 2W. At the same time, the 16 Hz calling signal is turned on for 1 second and turned off for 2 seconds and output to 2 W from the calling signal output unit 16. Therefore,
The CO trunk responds to the primary response and switches the 2W DC circuit to LOO.
If P, the CO trunk in-band ringer detects the loop detector 14 and turns off the output of the control signal transmitter 17 under the control of the controller 24 under the control of the CFS and the SFS.
And

Next, the OD trunk in-band ringer turns OFF both the CFS and the SFS.
, And controls the control signal sending unit 31 to
Is set to OFF. By this operation, the OD trunk in-band ringer confirms the primary response of the CO trunk and notifies the OD trunk of the primary response.
A wink pulse of several hundred msec is output from the signal generation unit 38 as G
Output as ND signal. Then, next, the OD trunk sends a push button signal (hereinafter referred to as a PB
T) is input to the 2W of the CO trunk via the in-band ringer for the OD trunk and the CO trunk. When the reception of the PBT is completed, the CO trunk opens the 2 W DC circuit and rings the bell of the designated telephone. The CO in-band ringer detects the 2W DC circuit OPEN by the loop detection unit 14, sends the RBT to the OD trunk side, and
The control signal transmitting unit 17 is operated under the control of the control unit 24 to turn on the CFS. On the other hand, the RBT inputs from the SLINE of the in-band ringer for the CO trunk and the RLINE of the in-band ringer for the OD trunk to the OD trunk via 4WR. The in-band ringer for the OD trunk is
CFSON is detected by the control signal detection unit 36, and the control signal transmission unit 31 is operated under the control of the control unit 39, and the SF
S is turned ON.

Next, when the designated telephone goes off-hook, the CO trunk sets the 2 W DC circuit to LOOP, so that the CO in-band ringer detects the DC circuit LOOP by the loop detecting section 14 and the polarity inverting section 15. Works,
The polarity of the DC voltage applied to 2 W is reversed, the RBT is stopped, and the control signal transmitting unit 17 is controlled to
FS is turned off. The OD trunk in-band ringer detects CFSOFF by the control signal detection unit 36,
The control signal transmitting section 31 is operated under the control of the control section 39 to turn off the SFS and enter the talking state with the SR signal as GRD. On the other hand, the CO in-band ringer detects SFSOFF by the control signal detection unit 22 and
Transition to the call state.

Next, the operation when the called party first puts the handset on-hook will be described. When the called party hangs up the handset, the 2 W DC circuit becomes OPEN, and the CO in-band ringer detects this in the loop detector 14 and operates the control signal transmitter 17 under the control of the controller 24. , CFS is turned ON. Next, in the in-band ringer for the OD trunk, the control signal
Detecting the FSON, operating the SR signal generation unit 38,
The SR signal transmitted to the OD trunk is OPEN. On the other hand, when the caller turns on the telephone, the OD trunk sets the SS signal to OPEN.
Is detected, the control signal transmission unit 31 is operated, and CFS,
SFS is set to ON. Therefore, the CO in-band ringer detects this by the control signal detection unit 22 and performs SFS
Is set to ON, and thereafter, both the in-band ringers enter a standby state.

Next, the operation when the caller first goes on-hook on the handset will be described. When the caller places the handset first, the OD trunk sets the SS signal to OPEN. Therefore, the OD trunk in-band ringer detects the SS signal by the SS signal detection unit 30 and controls the control signal transmission unit under the control of the control unit 39. 31 is operated to turn on the SFS. Also, O
At this time, the D trunk in-band ringer sends BT from 4WS. Since this BT is input to the 2W of the CO trunk via the in-band ringer, the called party confirms this busy tone and turns on the handset, and
As for 2W of the trunk, the DC circuit is OPEN. The CO trunk in-band ringer uses the loop detector 14
When the control signal transmission unit 17 is operated under the control of the control unit 24 and both CFS and SFS are turned on,
The in-band ringer for the OD trunk includes the control signal detection unit 3
6 detects this, and operates the control signal sending section 31 under the control of the control section 39 to turn on the CFS. Thereafter, both inband ringers are in a standby state. The busy / ringback tone transmitting section 23 provided for the in-band ringer for the CO trunk and the busy tone transmitting section 37 provided for the in-band ringer for the OD trunk both start up as soon as the in-band ringer is turned on. If not, send busy tone to CO trunk and OD trunk. The input of the control signal detection unit 22 includes an amplifier 20 for amplifying the received signal to an optimum level and an equalizer 21 for equalizing the line frequency characteristics of the RLINE flatly. Includes an amplifier 34 for amplifying a received signal to an optimum level and an equalizer 35 for flattening the line frequency characteristics of RLINE.

Next, the operation of the call signal will be described. In the in-band ringer for CO trunk, 2
A call signal input from W is transmitted through a hybrid transformer 25 of an in-band ringer for a CO trunk to a two-wire system / 4.
The signal is linearly converted and input to the echo canceller 26. Therefore, the echo canceller 26 deletes the echo component so that the call signal received from the RLINE does not enter the SLLINE side via the hybrid transformer 25,
The transmission level to the SLINE is set to an optimum value from the amplifier 27, and the communication signal is output via the line transformer 18 for terminating the SLINE. On the other hand, the speech signal received from the RLINE via the line transformer 19 is amplified to an optimum level by the amplifier 28, and the line frequency characteristics of the RLINE are equalized flat and the control signal is output to 2W. The signal is input to an equalizing filter 29 comprising a band rejection filter for preventing the signal, and a desired speech signal is output to 2 W via the hybrid transformer 25.

On the other hand, a call signal input from the OD trunk 4WS is input to the echo canceller 41 via the line transformer 40 of the in-band ringer for the OD trunk. Therefore, in the echo canceller 41, RLIN
The call signal received from E is sent to S
The echo component is eliminated so as not to go around to the LINE side, the transmission level to the SLINE is set to an optimum value by the amplifier 42, and the speech signal is output via the line transformer 32 for terminating the SLINE. On the other hand, the communication signal received from the RLINE via the line transformer 33 is amplified to the optimum level by the amplifier 43, and then the line frequency characteristics of the RLINE are equalized flatly and the control signal is output to the 4WR. The signal is input to an equalizing filter 44 including a band rejection filter for preventing the signal, and a desired speech signal is output to 4WR via a line transformer 45.

Next, the above operation will be described in detail with reference to an operation sequence diagram. 4 and 5 are diagrams showing an example of an operation sequence of the in-band ringer according to the present invention, and FIG. 4 shows a case where dial-in connection from an OD trunk to a CO trunk is performed. FIG. 5 shows an operation for ending a call after dial-in connection. First, the meaning of the terms used in the figure will be described.
The OFF state of the signal indicates the OPEN state, and the ON state indicates GND.
(Geo). OFF of CFS and SFS indicates stop of the control signal, and ON indicates transmission of the control signal. OFF of CFR and SFR indicates no reception of a control signal, and ON indicates reception of a control signal. 2WS indicates an output state from 2W to SLINE, 2WR indicates an input state from RLINE to 2W, and VOICE is a call signal. 2W
OPEN and LOOP of the (control signal) indicate that the polarity of the applied DC voltage has a positive polarity.
EN and REVLOOP indicate states where the polarity of the applied DC voltage is the reverse polarity. Also, in the part where the state change is displayed in the figure, the number is described, the order in which the state change occurs is displayed, and those in which the same number is described are:
It means that it causes a state change at the same time.

The operation of FIG. 4 will be described. First, when the telephone line is idle, both the in-band ringer for the OD trunk and the in-band ringer for the CO trunk are continuously transmitted with the control signals CFS and SFS ON, and the CFR and SF are transmitted.
R is both ON. Therefore, when the OD trunk receives a call and turns on the SS signal, the in-band ringer for the OD trunk turns off the CFS and turns off the SFS for one second.
N, output intermittently with 2 seconds OFF. For CO trunk in-band ringer, CFR is OFF and SFR is 1 second O
N, turning off intermittently after 2 seconds, detecting the incoming call, inverting the polarity of the voltage applied to the DC circuit to 2W of the CO trunk,
Send out a ringing signal (RINGER) consisting of z. Next, the CO trunk detects the ringing signal of 16 Hz, and sets the 2 W DC circuit to LOOP as a primary response. The CO trunk in-band ringer is a 2W DC circuit LOO
When P is detected and both CFS and SFS are turned OFF, O
The in-band ringer for the D trunk detects this and
S is turned OFF, and a wink pulse consisting of several hundred msec is sent to the OD trunk as a primary response signal. Next, after receiving the wink pulse, the OD trunk sends out a PBT to designate an extension number via 4WS, and sends a 2W of CO trunk via the in-band ringer.
To enter. When the CO trunk completes the reception of the PBT, it sets the DC circuit of 2 W to OPEN and sends a calling signal to call the telephone of the called party.

On the other hand, when the CO trunk in-band ringer detects that the 2W DC circuit has been opened, it turns on CFS and sends out RBT. O
When detecting the CFRON, the in-band ringer for the D trunk turns on the SFS, and sets the RBT to the OD trunk.
Is output. Next, when the called party goes off-hook on the handset, the CO trunk sets the 2W DC circuit to LOOP, so the CO in-band ringer detects this and detects 2W.
And the polarity of the DC voltage applied to
The transmission of T is stopped and CFS is turned off. By detecting the CFROFF, the in-band ringer for the OD trunk turns off the SFS of the own station and enters the talking state.

Next, the operation of FIG. 5 will be described. First, when the called party first hooks the handset (called party first),
Since the CO trunk sets the DC circuit of 2 W to OPEN, the in-band ringer for the CO trunk detects this and turns on the CFS. The OD trunk in-band ringer detects CFRON and turns off the SR signal to the OD trunk. Next, when the OD trunk outputs the SS signal OFF due to the caller's handset going on-hook, the OD trunk in-band ringer outputs the CF signal.
Both S and SFS are turned ON, and the CO trunk in-band ringer that detects this is set to SFSON, and both in-band ringers enter a standby state.

Next, when the caller first goes on-hook the handset (caller first), the OD trunk sends the SS signal to the O
Since it is FF, the in-band ringer for the OD trunk is
The SFS is turned on, and a BT indicating that the caller has gone ahead is transmitted. The BT is input to the 2W of the CO trunk via the in-band ringer, and is input to the called party's telephone as a busy tone. Then, when the called party confirms the busy tone and goes on-hook the handset, CO
Since the trunk opens the 2W DC circuit, C
The O trunk in-band ringer turns on both CFS and SFS. The in-band ringer for the OD trunk detects this and outputs the SR signal OFF to the OD trunk and turns on the CFS, and both in-band ringers enter a standby state. By enabling the above-described operation sequence, dial-in connection to the telephone accommodated in the PBX becomes possible.

[0026]

According to the present invention, as described above, claim 1,
For both 2 and 3, the in-band ringer has a polarity reversal function,
By enabling a predetermined operation sequence, the public line and the private line are interconnected using the in-band ringer,
Since the dial-in connection to the telephone accommodated in the PBX is made possible, a great effect can be exhibited in constructing an economical network.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an in-band ringer that enables PBX dial-in according to the present invention.

FIG. 2 is a configuration diagram showing one embodiment of an in-band ringer that enables PBX dial-in according to the present invention, and
3 shows an in-band ringer for an O trunk.

FIG. 3 is a block diagram showing one embodiment of an in-band ringer that enables PBX dial-in according to the present invention, and
3 shows an in-band ringer for a D trunk.

FIG. 4 is a diagram showing an example of an operation sequence of the in-band ringer according to the present invention, showing a case where a dial-in connection is made from an OD trunk to a CO trunk.

FIG. 5 is a diagram illustrating an example of an operation sequence of the in-band ringer according to the present invention, and illustrates an operation when a call is terminated after dial-in connection;

FIG. 6 shows an example in which a conventional in-band ringer is used to extend an extension.

FIG. 7 is a configuration diagram showing an example in which a public line and a dedicated line are interconnected.

[Explanation of symbols]

1. PBX, 2. In-band ringer, 3. Telephone, 4. In-band ringer, 5. Switching machine,
6. PBX, 7, 8 Inbandlinger, 9
··· Switchboard, 10 ··· PBX, 11 ··· In-band ringer for OD trunk, 12 ··· In-band ringer for CO trunk, 13a, 13b, 13c · · · Telephone, 14 ···
Loop detection unit, 15 ... polarity reversal unit, 1
6 ··· Paging signal output unit, 17 ·· Control signal sending unit,
18, 19-line transformer, 20-amp, 21-equalizer, 22-
Control signal detection section, 23 busy tone transmission section, 24 control section, 25 hybrid transformer, 26 echo canceller,
27, 28 ··· amplifier, 29 · · · equalization filter,
30 SS signal detector, 31 control signal transmitter, 32, 33 line transformer, 34
.. an amplifier, 35 .. an equalizer,
36 control signal detecting section 37 busy tone transmitting section 38 SR signal generating section 39
..Control unit, 40..Line transformer, 41
..Echo cancellers, 42 and 43
44 ... Equalization filter, 45 ... Line transformer

Continuation of front page (72) Inventor Atsushi Fujisawa 2-1-1 Kotani, Samukawa-cho, Koza-gun, Kanagawa F-term (reference) in Toyo Tsushinki Co., Ltd. 5K049 AA01 AA04 BB04 BB12 BB22 CC05 DD02 EE04 FF02 FF12 FF21 5K050 BB06 BB11 CC09 DD01 DD05 DD13 DD19 EE04 EE09 EE22 EE23 EE25 FF07 FF09 FF23 GG06 GG08 GG15 5K051 AA05 BB01 CC08 DD03 DD07 DD12 HH01 HH24 HH25 JJ02

Claims (3)

[Claims] An exchange provided with an OD trunk is connected to an in-band ringer for an OD trunk, a PBX provided with a CO trunk and containing a plurality of telephones is connected to an in-band ringer for a CO trunk, and the OD trunk is connected. In a network system in which the in-band ringer for CO and the CO in-band ringer are connected via a transmission path, a control signal input from the OD trunk is controlled by the in-band ringer for OD trunk to control a plurality of signals in a voice band. The CO in-band ringer converts the plurality of input control signals into DC circuit control signals and outputs the signals to the CO trunk, and outputs the signals to the CO trunk. Is output to the CO trunk in-band ringer. The OD trunk in-band ringer converts the plurality of control signals into a plurality of control signals having frequencies within the voice band and outputs the control signals to the OD trunk in-band ringer. When outputting to the trunk, the in-band ringer for the CO trunk is provided with a polarity inversion section of the DC applied voltage so that the polarity of the DC applied voltage to the CO trunk can be inverted, and the control signal is input / output according to a predetermined operation procedure. An in-band ringer that enables PBX dial-in, which is characterized by being configured. 2. The CO trunk in-band ringer comprises:
A loop detection unit for detecting the opening and closing of a DC circuit in a two-wire communication path, a polarity inversion unit for inverting and reversing the polarity of a DC voltage applied to a CO trunk, and a call signal for outputting a call signal to the CO trunk An output unit, a control signal sending unit that outputs a plurality of control signals each having a frequency within a voice band to an opposing in-band ringer, a line transformer that terminates a transmission line, a line transformer that terminates a reception line, and the reception line An amplifier for adjusting the level of a control signal received from an equalizer, an equalizer for equalizing the line frequency characteristics of the reception line, and a control signal detection for detecting a plurality of control signals composed of in-band frequencies received from the reception line A busy / linkback tone transmitting unit for transmitting a busy tone to the two-wire communication path and transmitting a ringback tone to the transmission line; A control unit for controlling the internal each part,
A hybrid transformer that terminates the two-wire communication path;
An echo canceller that eliminates an echo component in which a reception signal from the reception line goes to the transmission side via a hybrid transformer, an amplifier that adjusts an output level to the transmission line, and adjusts a reception level from the reception line. 2. The PBX according to claim 1, comprising an amplifier for outputting to a two-wire communication path, and an equalizing filter for equalizing the line frequency characteristics of the receiving line flat and blocking a control signal frequency component. An in-band ringer that allows dial-in. 3. The in-band ringer for an OD trunk,
An SS signal detection unit for detecting an SS signal output by the OD trunk, a control signal transmission unit for outputting a plurality of control signals having a frequency in a voice band to a transmission line, a line transformer for terminating the transmission line, and a reception line , An amplifier for adjusting the level of a control signal received from the receiving line, an equalizer for flattening the line frequency characteristics of the receiving line, and an in-band frequency received from the receiving line. A control signal detection unit for detecting a plurality of control signals, a busy tone transmission unit for transmitting a busy tone to a 4-wire reception communication line and a transmission line, and an S to the OD trunk
An SR signal generating unit for outputting an R signal; a control unit for controlling each unit in the apparatus; a line transformer for terminating a 4-wire transmission communication path connected to the OD trunk; An echo canceller for canceling an echo component wrapping around to the transmission side via a path, an amplifier for adjusting the output level to the transmission line, and an amplifier for adjusting the reception level from the reception line and outputting to the 4-wire reception communication path And an equalizing filter for equalizing the line frequency characteristic of the receiving line flat and blocking a control signal frequency component, and a line transformer for terminating a four-wire receiving communication path. 1. An in-band ringer that enables PBX dial-in according to 1.