JPS5897949A - Ring trip system - Google Patents

Abstract

PURPOSE:To obtain a small-sized call signal sending circuit packaged to high density in an exchange by discriminating that the counted value of a call signal current corresponding to a period exceeding a reference value exceeds a threshold value, and detecting a DC current to be superposed upon the call signal current. CONSTITUTION:This system is provided with a circuit CMP1 which compares a call signal current sent out of a call signal sending circuit 1 with a prescribed reference value, a counting circuit CTR which counts up one by one at a prescribed period when it is decided on the basis of the comparison result that the call signal current exceeds the reference value and also counts down one by one at a prescribed period during a period other than said decision period, and a comparing circuit CMP2 which compares its counted value with a prescribed value. Then, the comparing circuit CMP2 discriminates that the counted value exceeds the threshold value, then a DC current to be superposed upon the call signal current is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ring trip method, particularly a ring trip method in a calling signal sending circuit of a telephone exchange. FIG. 1 is a diagram showing an example of a conventional ring trip method for a calling signal sending circuit. In Figure 1, from the ringing signal power source 1 to the resistor 2
) and via the DC power supply 6, terminals 3 and 4
A ringing signal current 1r is supplied to the telephone 5 connected to the
Ring the bell and make it move. Since a capacitor is inserted in the bell circuit of the telephone 5, the direct current 1d is not sent out from the direct current power supply 6 unless the subscriber responds. In such a state, only an alternating current voltage due to the ringing signal current 1r is generated across the resistor F, and is blocked by the low-frequency f wave generator constituted by the resistor 8 and the capacitor 9, and the transistor 11
There is no such thing as Luko. When the called party answers in such a state, the bell circuit of the telephone 5 is removed and a DC loop circuit is formed, so that a DC current 1d flows superimposed on the ringing signal current 1r, and a A DC voltage is generated together with the AC voltage. The capacitor 9 is charged by the DC voltage, and when the terminal voltage of the capacitor 9 exceeds the breakdown voltage of the constant voltage diode 12, the transistor 11 is energized, the relay 13 is operated, and the terminal 14 is connected from the contact 1 to the terminal 14.
sends a ring trip signal RTO to notify the processor of the called party's response in a known manner.

As is clear from the above explanation, in the conventional ring trip method, a large capacity capacitor is used to detect the ringing signal current 1rl (DC current that flows superimposed when the called party answers), and a low-frequency f-wave As a result, the miniaturization of the calling signal sending circuit using L8 technology or the like is hindered.

The purpose of the present invention is to eliminate the drawbacks of the conventional ring trip method as described above, and to avoid using large parts ('L1
This purpose is to realize a ring trip method that can be realized using three engineering technologies.
a first comparison circuit that compares a calling signal current sent out by the calling signal sending circuit with a predetermined reference value;

a counting circuit that adds one address at a predetermined cycle during a period in which the calling signal current is determined to be equal to or higher than the reference value by the second comparison circuit, and subtracts one address at the cycle other than the period; a second comparison circuit that compares the counted value with a predetermined threshold; and the second comparing circuit determines that the counted value exceeds the threshold; This is achieved by detecting direct current.

An embodiment of the present invention will be explained below with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing a ring trip method according to an embodiment of the present invention in a calling signal sending circuit, and FIG. 3 is a diagram illustrating the operation sequence in FIG. II2. Note that the same reference numerals indicate the same objects throughout the figures.

In fig.

Operational amplifiers 15 and 16. and resistance 1'F to 20
constitutes a comparator circuit OMP l, which includes a counter 23 and a subtracter 2.
4. Numerical comparator 35. Shift register 25° flip-flop 26. Gates 27 and 2B are counting circuits OT y
A decoder 29 . Tsuritsub Flop 3
0. A comparison circuit CMF2 is configured. Similar to FIG. 1, in FIG. 2, only the ringing signal current 1r as shown in FIG. 3 is supplied to the telephone 5 connected to terminals 3 and 4 until the called party answers. The comparison circuit OMPI converts the alternating current voltage generated across the resistor 2 from the calling signal current 1rK to a predetermined standard 1 [fF! For example, 0 volts is used as a reference value for comparison, and when the AC voltage is O volts or more, the comparison circuit output FITP is set to a logic value IK&, and when the AC voltage is 0 volts or less, the comparison circuit output FTP is set as Set logical value OK stage. Therefore, for the ringing signal current 1r shown from time tl to t in FIG. 1113, the comparison circuit output RTP is
, and logical value IK at t, to t, set to logical value O at time t, to t4 and from 1° to t. The comparison circuit output FITP is output from the counting circuit OTI'? 7
After being synchronized with the look lock signal OL to a predetermined period, for example 8 km, by the flip-flop 26, the signal is input to the counter 23 and the shift register 25. The count 923 indicates that the input synchronized comparison circuit output FTP is a logic value of 1.
In this case, one addition is made using the 8 kHz clock signal OL, and when the comparator circuit output FTP has a logical value of 0, one subtraction is made from the 8 kHz clock signal CLK. Further, the subtracter 24 subtracts a predetermined value M from the count value K of the counter 23, and the value comparator 35 initializes the counter 23 to 0 since it is N-M2O. The shift register 25 and the gate 2 constitute a well-known differentiating circuit, which detects the conversion point (times t! and is) of the comparison circuit output FTP from the logic value l to the logic value 0, and outputs the setting signal LD.
is supplied to the counter 23.

The counter 23 responds to the setting signal IJDK, and the subtracter 24
Set the count value to the initial setting value N-M supplied from 0
(Note that the 1 time interval t, to t,/and 1 to R are determined by the delay time provided by the shift register 25.)
Therefore, the count value N of the counter 230 increases from 0 to 1 at time t%, and increases by 1 at time 1. .

It is initially set to N1-M until it reaches N, and reaches time H after death, and then decreases by - until it reaches time t, KO. The count value N is also transmitted to the decoder 29 of the comparison circuit OMP2.

When the decoder 29 detects that the received count value N is OK, it transmits a stop signal H to the counter 23 via the gate 2, which is in a conductive state due to the comparison circuit output FTP of the logical value O. , stop counting. The stop signal IH
teeth.

Counting [N is maintained OK from time point t until the start of the next addition (time point 14 in this case). Thus, from the point in time when the comparator circuit output FITP is again converted to a logical value 1, the counter 2
3 starts one-to-one addition, and at time t when the count value N reaches NIK again, the comparator circuit output FTP converts the logical value OK again to stop the addition, and at the first time point tl, the count value N is changed to N.
, -M, and then subtraction is performed until the count value N becomes 0. On the other hand, 1 point in time 1. When the called party answers, the telephone 5 receives a direct current 1 superimposed on the ringing signal 11 i r.
d is supplied. Note that due to the decrease in the internal impedance of the telephone 5 due to the response, the ringing signal current ir itself also increases (see FIG. 3). As a result, the comparator circuit c'hipx applies the main strain across the resistor 2 from time t to t due to the ringing signal current ir and the DC current 1d which have increased since then.
,. The comparison circuit output FTP is set to a logical value IK1 from - to 1. And the comparison circuit output F'rP is set to a logical value of 0 at t, o to tss.

The counting circuit c'rp that received the comparison circuit output FTP is 6
8 kHz clock signal 0IIK from time t to 7-
The count value N at the ninth time t, where the time interval tl to t- is increasing compared to the time interval tl to t, or t4 to tl, is equal to the time t or t.
The N in , is different from the higher N. Thereafter, as described above, the setting signal LD is initially set to N and -M from time t to time t, and subtraction is performed until time t after death. Since it is significantly shortened compared to t@, the count value N only decreases to N until time t, and from time t, the addition starts again with N as the initial value. .

As a result, the count value N increases with time. on the other hand.

Comparison circuit OM P'li! The decoder 29 converts the received count value N to a predetermined threshold value N t (Nt>N,
), and when it is detected that the threshold value Nt has been exceeded, the flip-flop 32 is set via the conductive data (D) 30 from the calling signal sending instruction signal SDK received from the processing device or the like from the terminal 33. As a result, the flip 7
Ring trip signal R from 0 knob 32 to terminal r54
'f'O is output (at time tis) to notify the processing device etc. of the called party's response.

As is clear from the above description, according to this embodiment, the comparator circuits cupx and 0MF2 and the stitch count circuit 0'rR do not use large parts such as large capacity capacitors, and have a structure that allows high-density cleaning. have.

Note that FIGS. 2g and 3 are only one embodiment of the present invention; for example, the count value N of the counter 230 is.

The initial setting is not limited to times tl to t≦ and t to tJ, and the conversion point 1 of the comparison circuit output FTP from logic value 0 to logic value l, for example, time 1. It is also considered that the initial setting is made at any point in the period determined by the delay time of the shift register 25, but the effects of the present invention do not change even in such a case. Further, the count value N of the counter 23 starts subtracting one address immediately after subtracting M at times t8 and tl, and when the absolute value of the count value N at the end of the subtraction is within a predetermined value, the count value N is Although setting it to O is also considered, the effect of the present invention does not change even in such a case. Also, the comparison circuit OMP1. The configuration of CMP2 or counting circuit 0TFI is not limited to that shown in the drawings, and many other modifications may be considered, but the effects of the present invention remain the same in either case. Further, the waveforms of the ringing signal current 1r and the DC current 1d are not limited to those shown in the figure.

Although it varies depending on the line conditions where the telephone 5 is connected, etc.
In either case, the effects of the present invention remain the same.

Furthermore, it goes without saying that the device that receives the calling signal is not limited to a telephone.

According to the present invention, it is possible to realize a ring trip method that does not require the use of large parts, and in addition to making it possible to miniaturize and high-density mounting of the ringing signal sending circuit of a telephone exchange, it is also possible to implement a comparison circuit. In addition, since the desired function can be realized using only logic circuits, it has a configuration that can be integrated into an integrated circuit, and with today's I.81 technology, it can also be configured on a single integrated circuit.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a conventional ring trip method for a calling signal sending circuit, FIG. 2 is a diagram showing a ring trip method according to an embodiment of the present invention in a calling signal sending circuit,
FIG. 3 is a diagram illustrating the operation sequence in FIG. 2. In the figure, 1 is a calling signal power supply; 2. 7. 8゜10, ]F to 20 are resistances, 3. 4. 14. 33
34 is a terminal, 5 is a telephone, and 6 is a DC power supply. 9 is a capacitor, 11 is a transistor, 12 is a constant voltage diode, 13 is a relay, and 1 is a contact. 15 and 16 are operational amplifiers, and 23 is a counter. 24 is a subtracter, 25 is a shift register, 26 and 32
is a flip-flop 2'F, 28.30 and 31 are gates, 29 is a decoder, 55 is a numerical comparator, cMpl
and CMP2 is a comparison circuit. 0'lR is the counting circuit, i= is the calling signal current, i (1 is the direct current, FTP is the comparison circuit output, LD is the setting signal s
Nl Nl + Nl and N are count values, OL is a black signal, NM is an initial value, and Nt is a threshold value. 8D is a calling signal sending instruction signal, 1'? TO is a ring trip signal, tl to t, and t, j, t≦. t& indicates time point.

Claims (1)

[Claims] (M In a ringing signal sending circuit of a telephone exchange. A 2-first comparison circuit that compares the ringing signal current sent out by the ringing signal sending circuit with a predetermined reference value, and a #1 first comparison circuit. a counting circuit that adds one at a predetermined cycle during a period in which the call signal current is determined to be equal to or higher than the reference value, and subtracts one at a ship cycle period other than the period; A second comparison circuit for comparison with a threshold is provided, and the second comparison circuit detects the direct current superimposed on the calling signal current by determining that the threshold has been exceeded. A ring trip method characterized by: A ring trip method according to claim 1, wherein the subtraction is stopped when the count value reaches Q.