DE2437114A1 - CHECKER FOR PULSE PARAMETERS FROM TELEPHONE NUMBER SWITCHES - Google Patents

Description

Patent attorneys pIn g. P ?. B H £ T Z

DIpI-: ro K. LAMPRSCHT

Dr.-lng. K. B ε Ei TZ Jf. Manchen 22, Stoirudorfotr. It

530-22.995P August 1, 1974

1. Vilnis Ansovich Dirin, Riga (USSR)

2. Andris Rudolfovich Ozols, Riga (USSR)

Checker for pulse parameters of telephone number switches

The invention relates to communications technology, in particular a device for checking the pulse parameters of telephone number switches (briefly called tester), who are responsible for checking the number switches both before and after they are installed in the telephone set is used.

A well-known checker for pulse parameters of telephone number switches contains a reference pulse generator whose output

530- (P 52 327/2) -Hd-r (8)

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gang is connected to the input of an AND element, a counter to record the duration of the number switch pulses, whose The input is connected to the output of the AND element and its output is electrical via a decoder with a display means is connected, a number switch pulse counter, a resistor that is connected to the resistance of the microphone from the telephone set forms a voltage divider for the voltage of the supply source and a center tap connected to the number switch to be tested has, and a threshold value circuit, the input of which is connected to the center tap of the supply voltage divider (see. SU inventor's certificate 242 239, class HO4 m 3/22).

With this tester for pulse parameters of telephone number switches however, it is impossible to determine both the duration of each pulse corresponding to the separation of the number switch pulse contacts as well as the duration of each impulse that occurs when these contacts are closed, because one measures by means of the Number switch pulse duration counter only the total time of the pulse contact separation and closing, which corresponds to the choice of number 0.

Another shortcoming of the well-known examiner is that no examination of the permanent relationship between two successive separating and closing processes is possible and only the mean value of the ratio of all separating processes to all closing processes is determined.

Another shortcoming of the known tester for pulse parameters of telephone number switches is that the test the time interval between the end of the last disconnection of the pulse contacts and the beginning of the disconnection of the number switch

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contacts that bridge the speech circuit, only when dialing the number 0 can be done, with certain difficulties and a. There is a great loss of time in the mass testing of Nura mems switches .

To carry out such a test, the known tester has a special counter for determining the time interval between the termination of the last disconnection of the impulse contacts and the beginning of the disconnection of those bridging the speech circuit Contacts, which complicates the circuit construction.

The invention is based on the object of a test for pulse parameters to create of telephone number switches, the circuit structure of which allows the time interval between the end of the last subsequent separation of the pulse contacts and the beginning of the separation of the speech circuit parallel to check lying contacts when dialing any digit and at the same time both the duration of the separation of the number switch contacts corresponding pulse as well as the duration of each pulse corresponding to the closure of these contacts, as well as to simplify the circuit structure of the whole tester.

This task will switch with a tester for pulse parameters of telephone Num mems, with a reference pulse generator including one at the first input of a first AND gate lying output, with a first number switch pulse duration counter, the first input of which is connected to the output of the first AND element and its output via a first decoder is electrically connected to a display means, with a num-

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switch impulse counter, with a resistor that, together with the resistance of the microphone of a telephone set forms a voltage divider for the voltage of a supply source and one to the to be tested number switch has connected center tap, and with a threshold value circuit, the input of which is connected to the center tap of the voltage divider is connected, achieved according to the invention by a pulse contact set for measuring the duration of each of the separation of the number switch corresponding pulse provided second AND element, the first input to the output of the reference pulse generator is connected and the second input is connected to the first output of the threshold value circuit, through a second Number switch pulse duration counter for separating the pulse contact set of the number switch, the first input of which is connected to the output of the second AND element and whose output is electrically connected via the second decoder to the display means, which is a display device for discrete Represents quantities with the inputs corresponding to the outputs of the first and the second decoder, through a NOT element, its Input is connected to the center tap of the supply voltage divider and its first output to the second input of the first AND element is located, a controller for the initial counter state, from which connected is the input with the second output of the threshold value circuit, the first output with the second input of the first number switch pulse duration counter and the second output to the second input of the second number switch pulse duration counter and the input of a number switch pulse counter, for measuring the time interval between the termination of the last disconnection of the Pulse contact set and the beginning of the separation of the voice circuit bridging contact set of the number switch by a

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Trigger and a NOR element, at the three inputs of which the second output of the NOT element, the first output of the threshold value circuit or the output of the trigger, the first input of the trigger being connected to the first output of the actuator and the second input connected to the corresponding output of the first decoder and the output of the NOR gate to a time interval indicator for the display of exceeding the maximum value of the mentioned Time interval between the end of the last disconnection of the pulse contact set and the beginning of the separation of the contact set of the number switch bridging the voice circuit is switched, wherein the first AND gate, the first number switch pulse duration counter and the first decoder for measuring the duration of each Impulse are determined, which corresponds to the closure of the impulse contact set from the number switch.

It is useful that between the outputs of each decoder and a memory is connected to the corresponding inputs of the discrete variable display device in which the number of memory cells the number of corresponding outputs of the corresponding decoder is the same and is an electronic switch that is common to all memory cells and is constructed on the base of the first transistor lies, to the emitter of which the first resistor is connected, between its base and the negative pole of the supply source, a second resistor and a third resistor is connected between the collector and the negative pole of the supply source, and each memory cell is equipped with a second and a third transistor of different conductivity types and with a fourth resistor, that the base of the second transistor from the direct (pnp) conductive

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type serves as the input of the cell and to the corresponding output of the corresponding decoder is connected, the collector of the second transistor to the base of the third transistor from inverse (npn) conductivity type is connected between the collector of the third transistor and the base of the second transistor is connected to the fourth resistor and the collector of the third transistor the corresponding input of the display device for discrete quantities is connected to the emitters of the third transistors of all memory cells are interconnected and connected to the negative pole of the supply source and the emitters of the second transistors of all Memory cells are also connected to one another and connected to the collector of the first transistor, whose base, if the memory lies between the outputs of the first decoder and the corresponding inputs of the display device for discrete quantities, with is connected to the second output of the controller, and, if the memory is between the outputs of the second decoder and the corresponding Inputs of the display device is switched for discrete quantities, is connected to the first output of the actuator.

When the inventive checker for pulse parameters of telephone number switches Used for mass testing the number switch, it is possible to change the ratio of the duration of the Impulse contact separation for the duration of the impulse contact closure, the sum of these time intervals and the number of number switch impulses and at the same time the time interval between the end of the last pulse contact separation and the beginning of the separation to test the contacts bridging the voice circuit when dialing any number.

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All of this enables a great reduction in the amount of work for checking, checking and setting the pulse parameters of number switches, a significant increase in the reliability of the Testing and improving the quality of the number switch.

The invention is illustrated in the following description of exemplary embodiments explained in more detail using the drawing. Show it:

1 shows a block diagram of the pulse parameter tester according to the invention of telephone number switches with a number switch to be tested,

2 shows another block diagram of another exemplary embodiment the examiner according to the invention for Impulspärämeter of telephone number switches with a to checking number switch,

Fig. 3 vori a memory for the examiner for Impulspärämeter Telephone number switch according to the invention, and

4 shows a diagram of voltage pulses at the center tap of the supply voltage divider according to the invention.

The tester for impulse pärämeter of ferric intercom number switches contains a Refererizimpulsgenerätor 1 (Fig. 1), the output of which is connected to the first inputs of AND gates 2 and 3 is.

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The reference pulse generator 1 is based on a known quartz generator built up and delivers reference pulses at the output with a repetition frequency corresponding to the discontinuity of the tester. The AND terms 2 and 3 represent common and widely used coincidence circuits. The output of AND gate 2 is connected to the first input of a number switch pulse duration counter 4, the output of which via a decoder 5 with the corresponding Inputs of a display device 6 for discrete quantities is electrically connected, which is carried out according to a known circuit and holds the information until new information arrives, the number of its inputs being the number of outputs of the decoder 5 and a decoder 7, the outputs of which are also connected to corresponding inputs of the display device 6. Of the The input of the decoder 7 is at the output of a number switch pulse duration counter 8, the first input of which is connected to the output of the AND element 3.

The number switch pulse duration counters 4 and 8 together with the corresponding decoders 5 and 7, respectively, constitute known timers which have outputs for the entire measuring range required for measuring the number switch pulse duration, which correspond to each pulse duration value. In addition, the decoder 5 has an additional one Output 9 for the largest time interval between the end of the last pulse contact separation and the beginning of the separation of contacts, that bridge the speech circuit.

A number switch 10 to be tested has a pulse contact set 11, which consists of contacts 12 and 13, as well as a contact

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set 14, which bridges the speech circuit and consists of contacts 15 and 16. A contact 17 serves together with the contact 16 to short-circuit the contact set 11.

If the number switch 10 is separated from the telephone is tested, the tester has a resistor 18, the resistance of which corresponds to the resistance of the microphone in the telephone set is equivalent to. This resistor 18, together with the resistor 19, forms a voltage divider for the voltage of a supply source 20, and a center tap 21 of this voltage divider is used for connection of the entire examiner to the number switch to be tested The input of a NOT element 22 is connected to the center tap 21, which is constructed as an ordinary logic inverter or negator, the first output of which connects to the second input of the AND gate 2 is connected and the second output is connected to the first input of a NOR gate 23, which is also known as a logical or logic circuit is established and an output signal delivers only in the absence of a signal at all inputs of this circuit. The input of an electronic threshold value circuit 24, known per se, is also connected to the center tap 21 whose output a signal only appears if the level of the input signal is above a specified threshold value. The first exit the threshold value circuit 24 is connected to the second inputs of the AND gate 3 and the NOR gate 23, and the second The output of the threshold value circuit 24 is connected to the input of a controller 25 for the initial state of the counter, which after a known pulse shaper is built and in which a pulse through the Leading edge of the input pulse, but other pulses through the

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Trailing edge of this input pulse are generated. The first exit of the controller 25 is connected to the second input of the number switch pulse duration counter 4 and to the first input (delete input) of a trigger 26 with two separate inputs and two stable states switched. The second output of the controller 25 for the start of the counter state is with the second input of the number switch pulse duration counter 8 and with the input of a number switch pulse counter 27, which is a well-known discrete pulse counter with simultaneous numeric display. The second The input of the trigger 26 is connected to the output 9 of the decoder 5, and the output of the trigger 26 is at the third input of the NOR element 23, the output of which is provided with a time interval indicator 28 for the time interval between the end of the last disconnection of the number switch pulse contacts and the beginning of the disconnection is connected to the number switch contacts lying parallel to the speech circuit.

For testing a five-wire number switch shown in FIG 10, the tester has a deletion element 29 for deleting the numeric display of the number switch pulse counter 27, the output this clearing element 29 with the display clearing input on the number switch pulse counter 27 and the input is connected to contacts 30 and 31 of the number switch.

Referring to Fig. 2, there is another embodiment of the pulse parameter checker of telephone number switches shown. This embodiment of the tester is used for testing a two-wire number switch 10 is used, which is built into a telephone set. A resistor 32 is symbolic of the resistance

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the value of the telephone microphone is drawn in and forms a züsa'mtheft with the resistor 19 a voltage divider for the voltage of the supply source 20. When testing such a two-wire number switch 10 is the display clear input on the number display pulse counter 27 connected to a display clear button 33 »

In contrast to the block diagram shown in FIG. 1, Weist the tester shown in Fig. 2 has a memory 34 on j whose inputs are connected to the outputs of the decoder 5, as well as a similar one Memory 35, the inputs of which are connected to the outputs of the decoder 7.

The outputs of the memories 34 and 35 are connected to the corresponding Inputs of the display device 6 for discrete quantities connected «Äüßefdem a special input 36 is provided in the memory 34 ^ which is connected to the second output of the controller 25 for the initial counter status. At the first output of the actuator 25 there is a separate one Input 37 of memory 35 * Otherwise, this is in FIG. 4 2 The block diagram of the tester according to the invention shown is similar to that shown block diagram of the first shown in FIGS Embodiment of the examiner built *

In addition, in FIGS. 1 and 2, arrows pointing outward from the food source 20 indicate the lines of this food source, eh structural units And circuits of the examiner for impülspärämeter from Ferhsprechä'ppä = rate-i'JummerhsGhaiterft äft.

ϊη Fig. 3 shows the memory M ^ The memory 35 is similar in structure »

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The memory 34 contains memory cells 38, the number of which the number of outputs of the decoder 5 corresponds, as well as an electronic switch 39 common to all memory cells 38, which is connected to a Transistor 40 is populated. At the emitter of the transistor 40 there is a resistor 41, between the base of the transistor 40 and the negative pole the supply source 20 (Fig. 2), a resistor 42 (Fig. 3) is connected, and between the collector of the transistor 40 and the negative pole the supply source 20 (Fig. 2) is a resistor 43 (Fig. 3), the base of the transistor 40 as the input 36 of the memory 34 (or as input 37 of the memory 35) is used.

Each memory cell 38 has a transistor 44 with direct (pnp) conductivity, a transistor 45 with inverse (npn) conductivity and a resistor 46. The base of the transistor 44 serves as the input of the memory cell 38 and is connected to the corresponding output of the decoder 5 (or of the decoder 7 in the case of the memory 35). Resistor 46 is between the base of transistor 44 and the collector of transistor 45, the base of which is connected to the collector of transistor 44. The collector of the The transistor 45 is connected to a light source 47 of the display device 6, as which can be used a discreetly displaying coordinate light panel, whose coordinate field consists of transparent rectangular bars exists along the coordinate axes, each of which is assigned its own light source 47. The emitters of transistors 45 of all Storage cells 38 are connected to one another and to the negative pole of the supply source 20 (FIG. 2), and they are also connected to one another connected emitters of the transistors 44 (FIG. 3) of all memory cells 38 are connected to the collector of the transistor 40.

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4 is a timing diagram of the voltage at the center tap 21 of the voltage divider for the voltage of the supply source 20 is shown, with the voltage U on the ordinate axis and the voltage U on the abscissa axis the time t are plotted.

The checker for pulse parameters of telephone number switches works like this:

At the start time t (Fig. 4) of dialing a number are the Contacts 15 and 16 (Fig. 1) bridging the voice circuit are separated, and the dial of the number switch 10 is in its home position. The voltage U (FIG. 4) of the supply source 20 (Fig. 1) becomes proportional to the resistance values of the resistors 18 and 19 divided, the voltage value at the center tap 21 of the voltage divider U (Fig. 4) and the ratio of the voltage divider resistances depends.

At time t, the dial of the number switch 10

(Fig. L) rotated, and at the same time the contacts 30 and close 31 and the contacts 15 and 16 bridging the resistor 18, with the voltage taken from the center tap 21 of the voltage divider equals zero.

By closing the contacts 30 and 31, the canceling element 29 on the number switch pulse counter 27 is put into operation. At the output of the extinguishing member 29, a signal is generated that the indicated Deletes information and prepares the number switch pulse counter: 27 for operation. ■ '=. "

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At the next time t (Fig. 4) the dial rotates back, and the contacts 12 and 13 (Fig. 1) of the pulse contact set 11 are opened, with the center tap 21 of the voltage divider Taken voltage is equal to the voltage U (Fig. 4) of the supply source 20 (Fig. 1). Since the voltage U (FIG. 4) is higher than the threshold voltage U at which the threshold value circuit 24 (Fig. 1) responds, a signal appears at the outputs. The voltage U (Fig. 4) is calculated taking into account the following Inequality chosen:

^U l > ^U 3> V

Arrived from the second output of the threshold value circuit 24 (FIG. 1) the signal to the input of the controller 25, and the beginning of this signal causes the formation of a at the second output of the controller 25 Pulse that resets the number switch pulse duration counter 8 to the initial state and the presence of the first pulse in the number switch pulse counter 27 holds. At the same time that will Signal from the first output of the threshold value circuit 24 is given to the second input of the AND gate 3, the first input this AND element 3 as well as the first input of the AND element 2 constantly receives the reference pulses from the reference pulse generator 1 are fed. From the output of the AND element 3, the reference pulses reach the input of the number switch pulse duration counter 8, which begins to count the duration of the pulse A (Fig. 4), which is the opening of the pulse contact set 11 (Fig. 1) in the number switch 10 corresponds.

At time t (Fig. 4) the contacts 12 and 13 of the im-

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Pulse contact set 11 (Fig. l) closed. The tension at the center tap 21 becomes equal to zero, and after the fall of the signal supplied by the output of the threshold circuit 24 appears at the first output of the actuator 25 a pulse which sets the number switch pulse duration counter 4 and the trigger 26 in the initial state. Of the Number switch pulse duration counter 8 closes the countdown of the duration of the separation of the pulse contact set 11 (Fig l) corresponding Pulse A (Fig. 4), and from a certain output of the decoder 7, which corresponds to the determined duration of this pulse A (Fig. 4) corresponds, a signal is given to a corresponding input of the display device 6 (Fig. 1), which records this duration.

At the same time, 22 appears at the outputs of the NOT element a signal which arrives at the second input of the AND gate 2, wherein from the output of the AND gate 2 reference pulses are given to the input of the number switch pulse duration counter 4, which the Counting of the duration of the pulse B (Fig. 4) begins, which corresponds to the closure of the pulse contact set 11 (Fig. 1) of the number switch 10 .

At the next point in time t- (FIG. 4) the contacts 12 and 13 (Fig. L) of the pulse contact set 11 reopened, with the from Center tap 22 taken voltage equal to voltage U (Fig. 4), the outputs of the NOT element 22 (Fig. 1) do not deliver a signal, and the number switch pulse duration counter 4 stops counting the duration of the closing of the pulse contact set 11 (Fig. 1) corresponding pulse B. (Fig. 4). From a certain outcome of the decoder 5, which corresponds to the determined duration of the pulse B (Fig. 4)

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(Fig. 3) in the memory 35 up to time t (Fig. 4) is the Transistor 44 (Fig. 3) blocked. Consequently, the transistor 45 is also blocked, since the bias voltage blocking the transistor 44 is applied to it Input from the voltage divider for the voltage of the supply source 20 (Fig. 2) is applied, which is through the resistors 41 (Fig. 3), 43 and is formed by the resistance of the opened transistor 40.

At the next point in time t, when the signal appears, am Input of a certain memory cell 38 (Fig. 3), the transistor 44 and consequently the transistor 45 open, since the feedback via the Resistor 46 contributes to the avalanche-like opening of transistor 45.

The open state of the transistor 45 corresponds to that connected State of the light source 47 corresponding to the respective memory cell 38.

At time t (Fig. 4) the initial state setting of the number switch pulse counter (8) (FIG. 2) no signal appears at the input of the respective memory cell 38 (FIG. 3), whereby the open State of the transistors 44 and 45 is obtained by the feedback provided by the resistor 46.

The resistor 41, which is via the open transistor 40 in the common circuit of the emitters of transistors 44 of all memory cells is on, limits the collector current of each transistor 44 and consequently the base current of each transistor 45.

At time t '(Fig. 4) the light source 47 (Fig. 3) is extinguished, d. H. the transistors 44 and 45 are activated by the

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status of the trigger 26 is the one-state of its output).

Furthermore, the set of contacts lying parallel to the speech circuit is used 14 (Fig. 1) at time t_ (Fig. 4) opened, and from Center tap 21 of the voltage divider "picked up voltage" equal to the voltage U (Fig. 4). At the second output of the NOT element 22 (Fig. 1) no signal appears, the first output of the threshold value circuit 24 also does not deliver a signal, since the threshold value circuit 24 from the signal with the voltage U (Fig. 4)

which is higher than the voltage U is solved.

d »

The signal is thus absent at all three inputs of the NOR element 23 (FIG. 1), and this causes the signal to be output at the output of the NOR element 23 and accordingly the registration of the exceeding of the maximum value of the time interval by the time interval indicator 28,

In contrast to the block diagram of the shown in FIG Tester for pulse parameters of telephone number switches, the number switch pulse counter 27 is reset after the measurement of the pulses corresponding to the selection of a number in the examiner according to FIG. 2 by pressing the button 33 to delete the display of the each time a number is dialed Counter 27.

If the display device 6, the coordinate light panel for discrete Display is used to display the number switch pulse duration the memories 34 and 35 are used.

In the absence of the signal at the inputs of the memory cells 38

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(Fig. 3) in the memory 35 up to time t (Fig. 4) is the Transistor 44 (Fig. 3) blocked. Consequently, the transistor 45 is also blocked, since the bias voltage blocking the transistor 44 is applied to it Input from the voltage divider for the voltage of the supply source 20 (Fig. 2) is applied, which is through the resistors 41 (Fig. 3), 43 and is formed by the resistance of the opened transistor 40.

At the next point in time t, when the signal appears, am Input of a certain memory cell 38 (Fig. 3), the transistor 44 and consequently the transistor 45 open, since the feedback via the Resistor 46 contributes to the avalanche-like opening of transistor 45.

The open state of the transistor 45 corresponds to that connected State of the light source 47 corresponding to the respective memory cell 38.

At time t (Fig. 4) of the initial setting of the number switch pulse counter (8) (FIG. 2) no signal appears at the input of the respective memory cell 38 (FIG. 3), whereby the open State of the transistors 44 and 45 is obtained by the feedback provided by the resistor 46.

The resistor 41, which, via the open transistor 40, is in the common circuit of the emitters of transistors 44 of all memory cells is on, limits the collector current of each transistor 44 and consequently the base current of each transistor 45.

At time t '(Fig. 4) the light source 47 (Fig. 3) is extinguished, i.e., transistors 44 and 45 are turned on by the action of the

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status of the trigger 26 is the one _f status of its output) .; ,, _{; J}

Furthermore, the demSprechstromkrei spa ^ _s Rachel lying j clock set 14, (Fig. L) at the time t_ (Fig. 4) opened, and the center tap of the voltage divider taken out from the 21 voltage is equal to the voltage U ">. (Fig. 4.) · Αίη. _; two ^ enj, output ^ des'NICHTS, - _iP ~: member 22 (Fig. 1) appears no signal, the first output of the threshold value circuit 24 also delivers no signal, since the threshold value circuit, 24 νοητ signal rn.it the \ voltage _f , 1% = «(Fi ^ g? IQ-aus; - ^ ,, which is higher than the voltage U ^, is .. _u . _I ;,",. ,,, ^; ..,;, _{: ;;} - ». _S -. · ...

This means that the signal is missing at all three inputs of the NOR element 23 (Fig. 1), and this causes the signal output at the output of the NOR gate 23 and accordingly ^ the registration. the. iJbgirÄGhirgitung the maximum value; of the time interval "if you do" the time interval indicator 28,

In contrast to the the measurement of the impulses corresponding to the choice, a "timmer", in the tester according to FIG. 2 by pressing the button 33 for each time after the choice, a number takes place. _;; Iös.c <hung; .com ^ _(display, counter _27; .. "■■ [■■ - ^ ■■:... -'- ■ ά ι Ϊ '.- λ ^. - :? V'0i {'ί ^: # ϊιϊΜη>:} -

, ^ _{; t} If as display.eg.erat 6., c | ^ _i .., ^ p ^^ 9ate.nr, ^ ia ^ h ^ ta ^ iL-i | ^ r; diS; kj | e- ^ used ad _? will ,,, w ^ f 4 ^e n, for dip ^ nzgi ^ e.ider ^ uinpj ^^ n ^ ehalter pulse duration die, memory 34; and i35 used. _r ,, => .- -j ,,. ^ i ·: .-.,> - »\. -j »/.;-.,

In the absence of the signal at the inputs of the memory cells 38

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the contacts) allows the tester according to the invention to be preferred as a tool for those involved in the adjustment of the equipment in the mass production of number switches and as a test device for testing the operability both before and after installation in telephones built-in number switches to use during the operation of the telephone sets.

The tester according to the invention shortens the test time, reduces the amount of work and increases the reliability of the test results.

Claims (2)

24371U claims 1. Checker for pulse parameters of telephone number switches, with a reference pulse generator including one on the first Input of a first AND element lying output; with a first number switch pulse duration counter, the first of which The input is connected to the output of the first AND element and its output via a first decoder with a display means is electrically connected; with a number switch pulse counter; with a resistance that goes along with the resistance of the microphone a telephone set forms a voltage divider for the voltage of a supply source and a number switch to be tested has affiliated tapping of funds; and with a threshold value circuit whose input is connected to the center tap of the voltage divider is connected, marked by one for measuring the duration of each disconnection of the number switch pulse contact set (ll) corresponding pulse provided second AND gate (3), whose first input to the output of the Reference pulse generator (l) is connected and its second input is connected to the first output of the threshold value circuit (24) is; 509887/0228 'V ·' 24371U by a second number switch pulse duration counter (8) for the separation of the pulse contact set (ll) of the number switch (10) corresponding pulses, the first input of which is connected to the output of the second AND element (3) and the output of which is connected via the second decoder (7) is electrically connected to the display means, which is a display device (6) for discrete quantities with the inputs represents corresponding to the outputs of the first (5) and the second decoder (7); by a NOT element (22), the input of which is connected to the center tap (21) of the supply voltage divider is connected and the first output of which is connected to the second input of the first AND element (2); a controller (25) for the counter initial state, connected by the is the input with the second output of the threshold value circuit (24), the first output with the second input of the first number switch pulse duration counter (4) and the second output with the second input of the second number switch pulse duration counter (8) and the input of a number switch pulse counter (27); for measuring the time interval between the end of the last one Separation of the impulse contact set (ll) and the beginning of the separation of the speech circuit bridging contact set (14) of the Number switch (10) by a trigger (26) and a NOR element (23), at the three inputs of which the second output of the NOT element (22), the first output of the threshold value circuit (24) and the output of the trigger (26) lie, the first input of the trigger connected to the first output of the controller (25) and the second input to the corresponding output (9) of the first decoder (5). 509887/0228 24371 H. is closed and the output of the NOR gate (23) to a time interval indicator (28) for the display of the exceeding of the maximum value of the mentioned time interval between the end of the last one Separation of the impulse contact set (11) and the beginning of the separation the set of contacts (14) of the number switch (10) bridging the voice circuit is connected; wherein the first AND gate (2), the first number switch pulse duration counter (4) and the first decoder (5) are intended to measure the duration of each pulse that causes the pulse contact set to close (ll) corresponds to the number switch (10). 2. Tester according to claim 1,
characterized, that between the outputs of each decoder (5 and 7) and the corresponding A memory (34, 35) is connected to inputs of the display device (6) for discrete variables, in which the number of memory cells (38) the number of the corresponding outputs of the corresponding decoder (5 or 7) is the same and one for all memory cells (38) common electronic switch (39) built on the base of the first transistor (40) is connected to the emitter of the first transistor Resistor (41) is connected, between its base and the negative pole of the supply source, a second resistor (42) is and between the collector and the negative pole of the supply source, a third resistor (43) is switched on, and each memory cell (.38) with one second (44) and a third transistor (45) of different conductivity types and equipped with a fourth resistor (46) is, 609887/0228 24371U ■ that the base of the second transistor (44) of the direct (pnp) conductivity type serves as the input of the cell and is connected to the corresponding output of the corresponding decoder (5 or 7) is, the collector of the second transistor (44) is connected to the base of the third transistor (45) of the inverse (npn) conductivity type is, between the collector of the third transistor (45) and the base of the second transistor (44) the fourth resistor (46) is and the collector of the third transistor (45) is connected to the corresponding input of the display device for discrete quantities, that the emitters of the third transistors (45) of all memory cells (38) interconnected and connected to the negative pole of the supply source (20) and the emitters of the second transistors (44) of all Memory cells (38) are also connected to one another and connected to the collector of the first transistor (40), the base of which if the memory (34) is between the outputs of the first decoder (5) and the corresponding inputs of the display device (6) for discrete variables is connected to the second output of the actuator (25) is and if the memory (35) is between the outputs of the second decoder (7) and the corresponding inputs of the display device (6) for discrete variables is switched on, to the first output of the controller (25) is connected. 509887/0228