JPS6333359B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a private branch exchange having a multi-frequency signal receiver that receives multi-frequency signals transmitted from a push-button dial telephone or the like.

The multi-frequency signal receiver of a conventional private branch exchange detects the start of the multi-frequency signal when receiving the multi-frequency signal. The structure is such that the activation signal is sent to the external device only at either the time point or the time point when the end of the multifrequency signal is detected.

The drawbacks of this conventional multi-frequency signal receiver will be explained using an automatic private branch exchange using a push-button dial telephone as an example.

In the automatic private branch exchange shown in FIG. 1, when a subscriber using an extension telephone 1, which is a push-button telephone, makes a call, the extension telephone 1 is sent to a multi-frequency signal receiver 5 through a line circuit 2 and a link 4 of a call path switch 3. Connected.

When the subscriber of the extension telephone 1 presses the pushbutton dial, a corresponding multi-frequency signal (for example, a two-frequency signal consisting of one frequency group from a high frequency group and one frequency from a low frequency group) is sent out. ,
The multi-frequency signal receiver 5 receives the signal. Then, the multi-frequency signal receiver 5 sends an activation signal to the central control unit 6 to indicate that it has received the multi-frequency signal, and also sends information indicating the type of the received multi-frequency signal to the central control unit 6.

Let us now consider the case of central office line origination connection. When the subscriber of the extension telephone 1 presses the push button of the central office number (for example, "0"), the corresponding multi-frequency signal is received by the multi-frequency signal receiver 5, and the information is sent to the central control unit 6. Reportedly. Then, the central control unit 6 connects the line circuit 2 and the office line trunk 7 through the link 8 of the communication path switch 3, and also opens the link 4 between the line circuit 2 and the multifrequency receiver 5.

If the subscriber of extension telephone 1 connects the above-mentioned line circuit 2 and office line trunk 7 with link 8 while holding down the push button, the office line calling number (“0” in the above example) will be changed. A multifrequency signal will be sent to the central office line. Although this multi-frequency signal is redundant for the station, the station processes this multi-frequency signal as the first digit, leading to incorrect connections. Become.
In order to prevent this erroneous connection, the multi-frequency signal receiver 5
It is necessary to adopt a configuration in which the central control unit 6 is not activated while receiving the multi-frequency signal, but is activated after detecting the end of the multi-frequency signal.

On the other hand, in the case of extension interconnection, the above problem does not occur, so it is possible to immediately execute the connection operation as soon as the start of the multi-frequency signal of the last digit of the extension number is detected. By doing so, the multi-frequency receiver 5 can be opened early and the usage efficiency of the multi-frequency receiver 5 can be increased, and
The connection operation can be completed early. In addition, even in the case of a central office line originating connection, at the point when the start of the multi-frequency signal of the central office line originating number is detected, the central control unit 6 performs various connection processes other than connecting the line circuit 2 and the central office line trunk 7 via the link 8. By doing so, after detecting the end of the multi-frequency signal of the central office line calling number, the connection operation is completed with only a few remaining processes, making the connection extremely quick. Complete. In order to realize these, the multi-frequency signal receiver 5 needs to be configured to activate the central control unit 6 when the start of the multi-frequency signal is detected.

However, conventional multi-frequency signal receivers send the activation signal to the central control unit only when the start of the multi-frequency signal is detected or the end of the multi-frequency signal. It is not possible to simultaneously prevent erroneous connections, increase the speed of connection operations at the time of central office line origination connection and extension line interconnection, and improve the usage efficiency of multifrequency receivers in extension line interconnection.

In order to eliminate the above-mentioned drawbacks, the present invention is configured such that the multi-frequency signal receiver sends a start signal to the central control unit twice, once when it detects the start of the multi-frequency signal and when it detects the end of the multi-frequency signal. It is.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a private branch exchange having a multi-frequency signal receiver according to the present invention will be described in detail with reference to the drawings.

An embodiment of the multi-frequency signal receiver according to the present invention is shown in FIG. In FIG. 2, a multifrequency signal is applied to an input terminal 10. In FIG. The supplied multi-frequency signal is
The signal is amplified by an amplifier 11 and then enters filters 12 and 13 where it is separated into a high frequency group and a low frequency group.
The outputs of these filters 12 and 13 are transmitted to the amplitude controller 1
4 and 15, the signal is supplied to selective filters 20 to 27 for separating each frequency. The outputs of the selective filters 20 to 23 for the high frequency group are supplied to the OR circuit 50, and the outputs of the selective filters 24 to 27 for the low frequency group are supplied to the OR circuit 51.
The outputs of the OR circuits 50 and 51 are supplied to an AND circuit 52. Therefore, when outputs are obtained from both high and low frequency groups simultaneously, the output of the AND circuit 52 is supplied to the guard time detection circuit 53. This circuit 53 is used to prevent malfunctions caused by voice and other noises.
If the output of the AND circuit 52 continues for more than a certain guard time, it outputs a logic "1". Furthermore, in order to prevent malfunctions due to instantaneous interruptions in the multi-frequency signal, this circuit 53 returns to a logic "0" output when the output of the AND circuit 52 is interrupted for a certain guard time or longer. Therefore, the relationship between the multifrequency signal input to the input terminal 10 and the output of the guard time detection circuit 53 is as shown in A and B of the timing chart of FIG. 3, respectively. The output of this guard time detection circuit 53 is outputted through an output terminal 54. Also,
The output of this detection circuit 53 is supplied to the gate terminals of flip-flop circuits 30-37. The input terminals of the flip-flop circuits 30-37 are supplied with the outputs of the selective filters 20-27, respectively, and when the output of the guard time detection circuit 53 rises, each of the flip-flop circuits 30-37 is connected to the respective selective filter 20 at that time. ~27 output values are stored. The outputs of these flip-flop circuits 30-37 are outputted through output terminals 40-47.
Output terminal 40 is connected to C in the timing chart in Figure 3.
The output waveform of is shown as an example. In the waveform C, the waveform before the rising point G of the output waveform B of the guard time detection circuit 53 is a value corresponding to the multifrequency signal received immediately before the multifrequency signal currently being received,
At the rising point G of B, it is set to a value corresponding to the multifrequency signal currently being received. This value continues until the next multifrequency signal is received.

On the other hand, the output of the guard time detection circuit 53 is input to pulse generation circuits 55 and 56. The pulse generation circuit 55 is activated by the rising edge G of the output of the guard time detection circuit 53, and generates a pulse with a constant time width as shown in FIG. 3D.
This occurs as shown in . In addition, the pulse generation circuit 5
6 is activated by the falling H level of the output of the guard time detection circuit 53, and generates a pulse with a constant time width as shown in FIG. 3E. These pulse generation circuits 55,
Since the output of 56 is supplied to the OR circuit 57, the output waveform of the OR circuit 57 becomes the waveform shown in FIG. 3F. The output of this OR circuit 57 is the output terminal 58
is sent as an activation signal to the central control unit.

With the above configuration, the activation signal is sent to the central control device twice through the output terminal 58, at the time when the start of the multifrequency signal is detected and the time when the end is detected. At that time, information corresponding to the multifrequency signal is output to the output terminals 40 to 47.

Further, the starting signal at the time when the start of the multi-frequency signal is detected and the starting signal at the time when the end of the multi-frequency signal is detected are distinguished from each other by the value of the output of the output terminal 54 which is the output of the guard time detection circuit 53. be able to.

In the above description, the outputs of the flip-flop circuits 30-37 are directly output to the output terminals 40-47, but a decoder circuit may be provided in the middle. In addition, output terminals 40 to 47, 54, 5
8 output signals in parallel, but some or all of these outputs may be converted into serial signals and sent to the central control unit. In addition, the pulse generation circuit 5
The functions of 5, 56 and the OR circuit 57 may be executed on the central control unit side.

As described above, according to the present invention, the activation signal is sent from the multifrequency signal receiver to the central control unit at each point in time when the start and end of the multifrequency signal are detected, so that the central control unit receives the multifrequency signal. It is possible to recognize the start and end of each point. Therefore, it is possible to prevent incorrect connection of central office line originating connections in private branch exchanges, speed up connection operations when connecting central office lines and interconnecting extension lines, and improve efficiency of use of multi-frequency receivers in interconnecting internal lines. It can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an automatic private branch exchange, FIG. 2 is a block diagram showing the circuit configuration of an embodiment of the multifrequency signal receiver according to the present invention, and FIG. 3 is the same as shown in FIG. 3 is a timing chart for explaining the operation of the embodiment. DESCRIPTION OF SYMBOLS 1... Extension telephone, 2... Line circuit, 3... Call path switch, 5... Multi-frequency signal receiver, 6... Central control unit, 7... Office line trunk, 10... Input terminal, 11
...Amplifier, 12,13...Filter, 14,15...Amplitude controller, 20-23...Selective filter for high frequency group, 24-27...Selective filter for low frequency group, 3
0-37...Flip-flop circuit, 40-47...
Output terminal, 50, 51...OR circuit, 52...AND circuit, 53...guard time detection circuit, 54...output terminal, 55, 56...pulse generation circuit, 57...OR circuit, 58...output terminal.

Claims (1)

[Claims] 1. In a private branch exchange to which extension lines and office lines are connected, and which has a multifrequency signal receiver that receives multifrequency signals and a central control unit, when the multifrequency signal receiver receives a multifrequency signal, The signal receiver transmits a start signal to the central control unit twice, once when it detects the start of the multifrequency signal, and once when it detects the end of the multifrequency signal, and at the same time transmits the received multifrequency signal. Based on the telephone number information sent from the multi-frequency signal receiver, the central control unit identifies whether the call is to the central office line or the extension line. However, when it is determined that the call is to the central office line, a connection operation is performed based on the timing at which the activation signal is sent at the time when the end of the multi-frequency signal is detected, and the call is to the extension line. A private branch exchange characterized in that when it is identified that the start of the multi-frequency signal is detected, the connection operation is performed based on the timing at which the activation signal is sent.