JPS5927538B2 - Response monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a response monitoring system, and more particularly to a response monitoring system for a subscriber's ringing signal in a telephone exchange.

FIG. 1 is a diagram used to explain a conventional response monitoring system.

In Fig. 1, SIG is a ring signal sound generator R and a DC power supply E. The calling signal generating device RGT is composed of an AC silent relay F, a resistor R2, a calling signal sending contact 50,
A calling signal sending/response monitoring circuit consisting of 51, L
INE is a subscriber line, and INE is a subscriber telephone. At the subscriber station, the HSo3HSI connects the hook switch, L
o is the inductance of the bell circuit, Ro is the DC resistance of the bell circuit, co is the capacitor of the bell circuit, R1 is the DC resistance of the communication circuit, the hook switch HSo is open when on-hook and closed when off-hook, and the hook switch HSI is Closes when on-hook, opens when off-hook. Also, Zlo
, Zll are the impedances of the subscriber line LINE. The calling signal sound source IR is a power source with an average voltage of 75V and an average frequency of 16H2. First, a conventional response monitoring system will be explained using FIG.

Since the ringing signal is sent to the on-hook subscriber's telephone equipment, hook switch HSo is open and HSI is closed. At this time, the calling signal sending contacts 50, 5
, when closed, earth-IR-F-50-Z10-L0
In the loop of =R0-C0-HSI-Zll-S1-R2-EO-ground, a ringing current of 16H2 flows through the bell circuit, and a bell in the subscriber's telephone equipment (not shown) rings.
DC power supply E. The current loop due to capacitor C. is cut off, and no direct current flows. Here, the AC non-sensing relay F does not operate because it is configured not to be sensitive to 16 Hz alternating current. When the subscriber picks up the handset or answers the telephone, the switch HS' closes and the HS
Since l is open, a DC loop is formed within the subscriber's telephone equipment. As a result, the earth-R-F-SO-ZlO-
With the R1-HSO-Zll-S1-R2-EO-earth lube, a DC current flows to the AC insensitive relay F, and the relay F operates. A subscriber's response can be detected by monitoring the closing/opening of the contacts of an AC non-sensing relay F (not shown) by a control device of the exchange (not shown). That is, the conventional response monitoring system uses an AC insensitive relay to separate 16 Hz AC current and DC current.

As described above, in the conventional method, it is necessary to separate the extremely low-frequency AC signal and the DC signal, which has the disadvantage that the AC and DC separation circuit becomes large and cannot be made economical. For example, the volume of a conventionally used AC static relay is about 170 cc. Next, we will explain the need for miniaturization and economicalization of response monitoring circuits based on recent trends in switch configuration technology.

With recent advances in integration technology, time-division communication channels using integrated memories and gates are being put into practical use. Although time-division communication paths are capable of switching digital codes, they cannot carry the high amplitude signals such as the talking currents and ringing signals required to operate existing telephones. For this reason, conventional space-division communication channels are installed at the back of the network.
Call current supply circuits, ringing signal sending circuits, response monitoring circuits, etc., which were designed to be economical by being commonly used by a large number of subscribers, must be installed in front of the network, and these circuits are not compatible with subscribers. is required. Comparing the number of these circuits between time-division communication paths and conventional space-division communication paths, we get
If the concentration ratio in the space-division communication path is n:1, the number of circuits in the time-division communication path is n times that of the space-division communication path. 1
The time for calling a subscriber in a call is approximately 10 seconds, and the usage time of the response monitoring circuit is extremely short.
This is about 30 circuits for 10,000 subscribers.

In other words, the concentration ratio of the response monitoring circuit is about 1000:3, and if you ignore other cost factors and focus only on the response monitoring circuit, the volume and cost can be reduced to about 3/1000 of the conventional response monitoring circuit. For the first time, the space and cost for space-division and time-division communication paths will be the same. To achieve this, it is no longer possible to use the conventional method using electromagnetic components, and electronicization and further integration are essential conditions. Since the number of circuits increases by about 1000 times, integrated circuits suitable for mass production are a particularly promising method for downsizing and economicalization. The present invention eliminates the conventional AC non-sensing relay in order to realize a response monitoring circuit that can be electronically and even integrated, and will be described in detail below.

First, the operating principle of response monitoring used in the present invention will be explained.

FIG. 2 shows the impedance of each part in the calling signal sending state. Items with the same numbers as in Figure 1 are
represent the same thing. In the present invention, the DC power source E in FIG. Since it is unnecessary, it is removed in Fig. 2, but if necessary due to conditions other than response monitoring, the DC power supply E is removed as in Fig. 1. You can also add . In FIG. 2, ZT is the impedance of the telephone at 16 Hz in the on-hook state, and is expressed by the symbol in FIG.
1) It becomes like the formula. RF is a resistance equivalent to the winding resistance of the relay F in FIG. 1, and VIR is the power supply voltage of the calling signal sound source R.

In FIG. 2, the loop current 11 is determined.

Assuming that 11 when the telephone is on-hook is IIN and 11 when it is off-hook is 1F, IIN and IIF are expressed by equations (2) and (3), respectively. ZT and R in existing telephone network
The specified value of 1 will be explained below.

The impedance of a telephone at 16Hz in on-hook state is specified to be 6KΩ or more for one telephone.
Furthermore, since it is permitted to connect up to three telephones in parallel to a pair of subscriber lines, ZT>2KΩ. On the other hand, the resistance R1 of the telephone in the off-hook state is 50Ω
It is specified as 220Ω. That is, ZTI and R
, and the relationship between the loop current 11N during on-hook and the loop current 11F during off-hook is 111N < 111FI, so if the difference between 11N and 1F is detected, response monitoring can be performed. It becomes possible. This is the operating principle of response monitoring in the present invention. FIG. 3 is a connection diagram of one embodiment of the present invention, in which R2 is the same resistor as R2 in FIG. 1, CODEC is a digital encoding circuit, and Ps
are the sampling pulse application terminals of the digital encoding circuit CODEC, REGO, REGl, REG2, REG3.
is a register, ANDO, ANDl, AND2, AND3
is an AND gate, COMO, COMl is a comparator, 0PT
0 is a subtracter, TO is a positive/negative determination circuit, T1 is a period determination circuit, and SCN is an output terminal for response monitoring results.

Next, the operation of this will be explained using FIG.

FIG. 4 is a diagram showing the operation sequence of the embodiment of FIG. 3. In FIG. 4, Vl is the digital encoding circuit CO
It is the input terminal voltage of the DEC, and is expressed as Vl=R2ll. Vl(Ti) is the value of voltage l at time Ti. Moreover, Ps is a digital encoding circuit CODEC
COUT is the output pulse of the digital encoding circuit CODEC, TOOUT is the output pulse of the positive/negative determination circuit TO, COMOOUT is the comparator COMO
, TlOutO and TlOUTl are the output pulses of the period determination circuit T1, and SCN is the output pulse of the response monitoring result. First, the digital encoding circuit CODE
C digitally encodes the value of the voltage 1 using an appropriate sampling period, that is, the sampling pulse Ps shown in FIG. 4, and an appropriate number of encoding bits so that the voltage V1 can be discriminated.

Register REGO is the encoded output of the digital encoder circuit CODEC, ie, C in FIG.

Accumulate one dose of UT. When the encoded output has been stored in the register REGO, the positive/negative determination circuit TO determines whether the voltage Vl at this time is positive or negative. For example, when the voltage l is positive, the positive/negative determination circuit TO outputs, that is, as shown in FIG. TOOU
Let T be 1. Comparator COMO compares the contents of register REGl with the contents of register REGO, and
Outputs 1 when O>REGl. The output of the comparator COMO, that is, COMOOUTl in FIG. 4 is 1 and positive/
When the output of the negative judgment circuit TO is 1, that is, the voltage Vl is positive, the output of the AND gate AND2 becomes 1, and the AND gate ANDO is opened to transfer the contents of the register REGO to the register R.
Transfer to EGl.

When this operation is repeated for half a period of the call signal having a positive voltage of 1, the contents of the register REG become the maximum value of the voltage V1 in the positive half period. That is, in the example of FIG. 4, after time T8, the register REGl contains 1(T4) to l(
The maximum value l(7) of T9) is written, and this content is written to the register REG2 at time Tll as described later. Next, the period determination circuit T1 determines the period of the voltage l. In the example shown in FIG. 1 is output to the TlOutO terminal at the first sampling time (T, O) after the change becomes negative, and TlOUTO is output at the second sampling time (Tll).
It is configured to output 1 to the l terminal.

These are TlOUTl and TlOUTl in FIG. 4. Subtractor 0PT0 extracts register R from the contents of register REGl.
Subtract the contents of EG2, (REGl) - (REG2)
Output. Comparator COMl compares the output of subtractor 0PT0 with the contents of register REG3, and is configured to output 1 when (output of 0PT0)>(REG3), and register REG3 has (2) and (3). R2(I
Since the value of lF-11N)/2 is stored in advance, when TlOOTO is 1 (time T,.) and (0PT0 output)> (REG3), 1 is output to the SCN terminal and control (not shown) is performed. The device can detect this and detect the subscriber's response. Output terminal TlOUTl is 1 (time Tll)
When , the AND gate ANDl opens and the register REG
Since the contents of l are transferred to register REG2, subtracter 0PT0 always subtracts the maximum value of voltage Vl in the previous cycle and the maximum value of V1 in the next cycle. In the embodiment shown in FIG. 3, the outputs of the digital encoding circuit CODEC can be multiplexed so that the subsequent circuits can be shared by multiple subscribers.

FIG. 5 is a connection diagram of another embodiment of the present invention, in which R2 is the same resistor as R2 in FIG.
OMl is a comparator, 0PT0 is a subtracter configured as a differential amplifier, SWO, SWl, SW2, SW2'', SW3
, SW4 is the switch, CTO, CTl, CT2, CT3
, CT4 is the control terminal of the switch, NT is the integrator, MEM
is a holding circuit, and SCN is an output terminal for monitoring the subscriber's response.

Next, the operation of this will be explained using FIG.

FIG. 6 is a diagram showing the operation sequence of the embodiment shown in FIG. Comparator COMO is a comparator for determining whether voltage 1 is positive or negative, and when voltage 1 is positive, its output is used to control terminal C.
Set TO to 1 and close switch SWO. Switch SW
When O is closed, the integrator 1NT starts integrating the voltage V1 and outputs a waveform like NTOut in FIG. When the integrator 1NT finishes integrating the positive half period of the voltage 1, the integrator NT holds the integrated value. Next, control terminal CT2
is set to 1, switches SW2 and SW2/ are closed, the output of the integrator NT and the output of the holding circuit MEM are subtracted by the subtracter 0PT0, and the value of (INT output) - (MEM output) is Output. Comparator COMl is subtractor 0
Compare the output of PT0 and the reference voltage Vref, and
When output>Ref, outputs 1 to the output terminal SCN. By setting the reference voltage Ref to R2{f (positive half cycle) 11F-f (positive half cycle) 11N}/4, the control device (not shown) detects the state of the SCN terminal and
If N is 1, it can be determined that it is a subscriber response. Next, control terminal CT2 is set to O to open switches SW2 and SW2', and control terminal CT3 is set to 1 to open switch SW3.
Close.

As a result, the contents of the holding circuit MEM are reset.
Next, by setting the control terminal CTl to 1 and closing the switch SWl, the contents of the integrator NT are transferred to the holding circuit MEM. Here, capacitor C3 in holding circuit MEM
The capacitance (also shown as C3) is set to C3-C1+C2 with respect to the capacitance of the two capacitors Cl and C2 (also shown as Cl and C2) in the integrator 1NT, so 1 of the voltage of the integrator 1NT /2 becomes the output of the holding circuit MEM. On the other hand, since the capacitances of the two capacitors Cl and C2 in the integrator 1NT are set equal, the voltage of the integrator 1NT output connected to the switch SW2 is 1/2 of the voltage of the integrator 1NT. . That is, the subtracter 0PT0 is configured to compare 1/2 of the output voltage of the integrator NT. Next, set the control terminal CT4 to 1 and switch SW4.
is closed, and the contents of the integrator 1NT are set.

With this configuration, the comparator COMl always compares the difference between the integrated value of the voltage I in the previous positive half cycle and the integrated value of the voltage V1 in the next positive half cycle with the reference voltage Vref. be able to.

In the above two embodiments, the loop current 1 or the voltage Vl was detected in its positive half cycle, but it goes without saying that the present invention can also be implemented by detecting it in its negative half cycle. As explained above, according to the present invention, the response monitoring circuit can be configured based on circuits suitable for computerization such as comparators and accumulators, so the circuit can be significantly miniaturized, and furthermore, it is possible to Since it is suitable for mass production, it has the advantage of being economical through mass production. In addition, since the method compares the value of the loop current 11 in the previous cycle with the value of the loop current 11 in the next cycle, the line impedance, the resistance in the ringing signal sending circuit, the output voltage of the ringing signal sound source, etc. can vary widely. Even if specified, the detection margin will not be reduced.

[Brief explanation of the drawing]

Fig. 1 is a diagram used to explain the conventional response monitoring system, Fig. 2 is a diagram showing the impedance of each part in the state of sending a calling signal, Fig. 3 is a connection diagram of one embodiment of the present invention, and Fig. 4 is 3, FIG. 5 is a connection diagram of another embodiment of the present invention, and FIG. 6 is a diagram showing the operation sequence of the embodiment of FIG. 5. SIG... Calling signal sending device, RGT...
...Call signal sending/response monitoring circuit, LINE...
...Subscriber line, installation...Subscriber telephone, F...
...AC silent relay, R...Call signal sound source, EO...DC power supply, SORA SL7HSO
HS "゜゜゜゜" contact, RORA Rl, R2, RF...
...Resistance, LO...Inductance, CO
...Capacitor, ZlO, Zll, Z, ...
・・・Impedance, COMO, COMl...
・Comparator, 0PT0...Subtractor, REGO,
REGl, REG2, REG3...Register,
CODEC...Digital encoding circuit, AND
O, ANDI, AND2, AND3...And gate, TO...Positive/negative judgment circuit, T1...
...Period determination circuit, Engineering NT...Integrator, ME
M...Holding circuit, SWO, SWI, SW2, S
W2', SNV3, SW4...Switch.

Claims (1)

[Scope of Claims] 1. In a telephone calling system that sends out a calling alternating current signal to a subscriber line, means for monitoring and detecting a loop current flowing through the subscriber line; means for determining a value indicating the magnitude of the loop current in the half cycle based on the current value detected from the current value; It is equipped with a subtracter that calculates the difference from a value indicating the magnitude, and a comparator that outputs an output when the output of the subtracter exceeds a predetermined reference value, and is called by the output of the comparator. A response monitoring method characterized by monitoring responses of subscribers. 2 The value indicating the magnitude of the loop current in the above half cycle is:
2. The response monitoring system according to claim 1, wherein the response monitoring method is the maximum absolute value occurring during the half cycle of the voltage occurring across the resistor inserted in series with the subscriber line. 3 The value indicating the magnitude of the loop current in the above half cycle is:
2. The response monitoring method according to claim 1, wherein the response monitoring method is an integral value over the half cycle of the voltage generated across the resistor inserted in series in the subscriber line.