DE1234060B - Checking device for multi-digit numbers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

G06f

German class: 42 m3 - 11/02

Number: 1234060

File number: W 38238IX c / 42 m3

Filing date: December 23, 1964

Opened on: February 9, 1967

The invention relates to a test device for multi-digit numbers, each indicated by an additional number or an additional number has been made capable of being tested, the latter from a multiplication scheme of the individual digits of the number to be checked with weights characteristic of the various positions and a checksum or some other addition of the intermediate results will.

It is known to make multi-digit numbers verifiable by one or more additional digits in order to Eliminate or at least exclude recording errors, in particular incorrect bookings or forgeries Reduce.

Even if, through careful training of the staff, the frequency of errors when keying in Account numbers depressed to below 1% can always change with a larger business volume there are still several incorrect bookings per day. This can lead to economic damage such. B. a financial institution, especially if amounts are credited to an incorrect account holder. In addition, a great deal of work is required to uncover and find the errors through cross checks and accounting closings.

The risk of such incorrect postings can be significantly reduced if the account number is used an additional number or an additional number is added, which is based on a certain calculation scheme the numerical sequence of the Convention itself results. If this calculation scheme is based on simple addition, e.g. B. limited to a checksum, then although the error is switched off that a single digit is typed, z. B. in place a 5 a 6 is keyed in.

The very common mistake that two adjacent digits are swapped, e.g. B. at In place of the account number 63645, the account number 63654 is keyed in, but is not removed, because both numbers add up to the same checksums. It can easily be seen that the interchanges are adjacent Digits can only be eliminated when multiplication systems are applied for example, if first the digits with different characteristic assigned to the positions "Weights" are multiplied before an addition scheme, e.g. B. a checksum is applied will. However, if in this way both the wrong keying of a digit and a position swap is switched off, it can be shown that this increases the frequency of errors by a factor On the order of 1: 100 depressed tester for multi-digit numbers

Applicant:

Walther office machines G. m. B. H.,

Gerstetten (Württ.)

Named as inventor:

Hans-Dietrich Fischer, Engenhahn (Taunus)

can be. This means that in practice, for example, about 1000 keystrokes per day on average, only one error per month occurs.

It is now known that selector and indication circuits are quite complicated in so-called full-key machines to provide, by means of which it can be checked whether the keyed number is inclusive the check digit falls under the check scheme. The effort for such testing devices, however, is so great that these have only been used for special purposes so far.

According to the invention, a test device is now to be proposed which all of the meets the requirements listed below:

a) The test device should be suitable for machines with a numeric keypad;

b) the test device should already display or enable or disable the machine before one of the machine's function keys is triggered, i.e. immediately after keying in each digit of a multi-digit number;

c) the test device should be both in terms of its space requirements and in terms of the required Significantly smaller and cheaper than known test devices, so that widespread use of them can be expected.

A test device according to the invention meeting these requirements differs from FIG the known devices in that a ten-key field in which the number to be checked locally is keyed in, key contacts and a position-dependent circuit are assigned and

709 508/143

that the key contacts and the circuit during or immediately after keying in a digit is sampled in pulses, with an intermediate result in an evaluation and storage device is saved immediately with or after keying in the last digit of the number to be checked an indication of the result of the test or the one machine which the test device delivers is assigned, released or blocked. In general, every switching device should be referred to as a “key contact” be understood, which is brought into a different state when a button is pressed.

In principle, the account number is checked before the mechanical is switched on Part of the machine revolution. A wrong keying in can never lead to an imprint on the Paper strips or even for transfer to a possibly connected punching device, e.g. B. a punch card or punched tape unit. At the same time, it becomes a cumbersome and often uncertain Identification of an incorrectly printed sequence of digits as well as the one in connection with this Avoid the stationary return transport of a car that has been tabulated by the engine release.

This solution idea is to be explained using an example game so that the later explanations can be explained easier to understand with regard to the specific features of the test device according to the invention will.

It is assumed that an account number including the last check number, which should be called 471126-2, is in a numeric keypad keyed in. The weights assigned to the various positions are 7, 6, 5, 4, 3, 2, 1. If the 4 is keyed in first in the usual way, then the one that depends on the position is located Circuit in such a position that a multiplication by 7 occurs. With the impulsive Scanning at the end of the key impression, the evaluation and storage device stores the number 28 accordingly. After releasing the key the buttons and moving the value carrier, z. B. the adjusting pin carriage of an adding machine, arrives the position-dependent circuit in such a state that a multiplication with the Weight 6 takes place. If the »7« is now keyed in, the circuit dependent on the position enters into one State in which a multiplication by 6 takes place. So it is in the evaluation and storage device in the case of pulsed scanning, the intermediate result at the end of the keystroke added to the number 28. When the value carrier moves on, the one dependent on the position comes Switching to a state in which a multiplication by 5 takes place. So it will be the intermediate result 5 added. Then the intermediate results 4, 6, 12 and 2 are added. The saved The total number is therefore 99. To simplify matters, it is useful if the evaluation and allows memory device to operate so that it resumes after a certain modulus has been reached starts to add from the beginning, and if the system is based on the modulus II in this case, see above no remainder remains in the evaluation and storage device. However, every time there is no remainder in the Storage device is present, this provides a release of the ready with passage of the pulse Machine that carries the numeric keypad. The decision about "right" or "wrong" is immediate and permanently on. The system is not limited to a specific number of digits. It can So 3 or 10 digit numbers are checked one after the other. The decision is made after each keying in one digit of a multi-digit number. The additional number 2 in the example mentioned is a matter of course has been calculated in such a way that adding up the intermediate results results in a number, which is a multiple of 11.

Characteristic of the invention is therefore the use of a ten-key field in contrast to a full keyboard and the pulsed scanning of the key impression with simultaneous Multiplication by a digit weight, each time with the pulsed sampling immediately the result is available. The test is therefore already ended before any function key on the machine has been actuated. However, this is a very important advantage as neither a transcript of a incorrectly entered account number or any incorrect calculation result, that would first have to be eliminated. When using the testing device for a booking engine on the other hand, the multiplications and additions are carried out by the booking engine itself would have to be, an operation of function keys would be required. The faulty one Key impression could not be removed again simply by pressing a delete key.

According to a preferred embodiment of the subject matter of the invention, the multiplication takes place of the digits with the weights by a multiplication circuit in which the precalculated Intermediate results or their values reduced by a certain modulus in The shape of intersection points can be controlled depending on the key impression and the location. Such a multiplication circuit can be formed by a matrix consisting of a grid intersecting ordinate and abscissa strands, with switching elements at the crossing points are arranged that can assume at least two different switching positions. the Matrix is connected to the individual key contacts and to the circuit dependent on the position.

In this way it is possible according to the invention to keep the effort very low. So it is not required that the multiplications in the form of successive additions by complicated Computing facilities are carried out. Rather, the pre-calculated results are in a matrix saved and controlled accordingly.

It is also particularly preferred that the location-dependent circuit of one with a printed circuit provided conductor element is formed during the successive Keying in the digits of the number to be checked is shifted or pivoted. In particular, can the conductor element can be designed in the form of a pendulum slider. Those scanning the pendulum grinder Contacts are connected on the one hand to the matrix and on the other hand to the key contacts. Be there always scanned several conductor strips of the printed circuit of the pendulum sander at the same time.

If a Her system is used as a basis, the matrix itself should have 100 points of intersection. Man

can, however, determine that the intermediate results "stored" at the intersection points are a have a double mirror image arrangement. It is now possible, according to a particular idea of the invention, significantly reduce the circuit complexity of the matrix. This is done according to a preferred embodiment achieved in that the matrix is once a mirror image at least half, but preferably twice in mirror image to a quarter, e.g. B. on 25 crossing points, is reduced by adding one half of the digit weights in the electronic Computing device and the other half a subtraction and / or adding one half the digits, e.g. B. the digits 1 to 5, an addition and the other half, z. B. the digits 6 to 0, a subtraction can be assigned in the electronic computing device.

The switching elements are expediently at the crossing points of the matrix diodes, in particular Transistor diodes.

It is also preferred that the circuit element carrying the printed circuit, in particular the Pendulum grinder, has an overtravel position, into which it briefly reaches when the positioning pin carriage returns, whereby a shutdown of the electronic computing device is effected, and from which it rebounds automatically into the zero position.

Furthermore, it is particularly preferred that the matrix and the electronic computing device in a flat base are housed, which roughly the shape of the machine, the test device is assigned, owns.

The numeric keypad can be connected to any booking addition or data processing machine, z. B. a punch card machine belong. The invention accordingly also relates to such Machines, provided they are equipped with a test device of the type described. The numeric keypad however, it does not need to have any other function, for example when only checking Numbers, e.g. B. of securities should be made. It is understandable that the check digit can also appear at the beginning or in the middle of the number to be checked at a certain point.

In the drawings is a preferred embodiment of a test device according to the invention shown. It shows

Fig. 1 is an overview of the arrangement of a conventional Booking or addition machine with a ten-key field and a subset, which the Contains the matrix and the electronic computing device of the test device,

F i g. 2 is a broken perspective and schematic partial view of the in the rest position the functional parts of the adding machine with the built-in parts of the test device,

Fig. 3 is a diagrammatic bottom view of the Ten-key field with the key shaft arrangement,

Fig. 4 is an enlarged plan view of the Numeric keypad with the key contacts,

Fig. 5 is a section of a key corresponding to the Line V-V in Fig.4, from which the arrangement a key contact can be seen,

F i g. 6 and 7 show a diagrammatic view to explain the blocking or enabling of the adding machine,

8 shows a schematic view of the circuit arrangement of the key contacts for the position of the actuating pin carriage,

9 shows the circuit of the matrix,

F i g. 10 the reduction of the 100 intersection points of the matrix which are required per se a total of 25 crossing points,

Fig. 11 is a schematic circuit diagram of the electronic Computing device.

In FIG. 1 shows a booking or adding machine 1 with a ten-key set which hereinafter referred to briefly as the parent machine, to which a subset 2 is assigned to the the machine can be placed or permanently connected to the machine as a unit. By doing Pedestal 2 is designed as a matrix 3 and is shown in FIG. 9 circuit gridwork shown in more detail and a known electronic computing device 4 shown in FIG. 11 is housed. the Other parts of the test device described in more detail below can be standard or can also be retrofitted in the parent machine. The width of the pedestal is z. B. about 20 to 25 cm, the depth 35 to 40 cm and the height 5 to 10 cm, from which it can be seen that the electronic Part of the test device according to the invention has an extremely small footprint.

The parent machine 1 has a ten-key pad 5. After each key press or against the At the end of the same, a pulse runs via a line 6 to the matrix 3 accommodated in the base 2 (See also Fig. 9) and via a certain grid point of this matrix to the electronic computing device 4 (see also Fig. 11), which checks whether the Previously keyed in sequence of digits corresponds to the examination scheme. If the sequence of digits is recognized as correct is, the mother machine 1 is via a line 7 to actuate one of the function keys 8, z. B. to non-calculating transcript of the keyed in account number, released.

The ten-key pad 5 contains, as shown in FIG. 4 (see also FIGS. 3 and 5), the keys T arranged in three rows and corresponding to the digits 1 to 9, a zero key and, if desired, also a double zero or triple zero -Button. A printed circuit board 9, a guide plate 10 and an insulating plate 11 have corresponding holes through which the keys T extend with their shafts 12. The holes in the guide plate 10 and the insulating plate 11 are so large that a contact ring 13 can be accommodated in them, which is pressed by a contact spring 14 designed as a spiral spring against a contact 15 of the circuit board 9 and when the button T is pressed by this is lifted.

The shafts 12 of the keys Γ are, as shown in FIG. 3 shows, bent in the usual way so that their ends 16 are parallel to one another. When the key is pressed, one of these ends is then pushed forward. The other keys T are locked against actuation as long as is known in machines of the type in question. The ends 16 of the key shafts 12 now act in a manner which is also known, as in FIG. 2 illustrated adjusting pins 17 'of an adjusting pin carriage 17. The adjusting pin carriage 17 serves at the same time as a value carrier; it becomes gradually or after each key press

also shifted so far from right to left in half steps when pressing and releasing the key T that the row of ends 16 of the key shafts 12 faces a new row of adjusting pins. Each step-by-step movement is visibly displayed via the position indicator 17 ″ connected to the positioning pin carriage 17 in the viewing hole of a scale graduation 17 ″ ″ attached to the machine. The keyed-in number is then finally fixed by setting the adjusting pins accordingly. The adjusting pins are then scanned by known means (not shown) for the purpose of rotating the writing number wheels or the counters causing an addition or subtraction.

In the present case it is mainly of interest that simultaneously with the advancement of the Stellsstiftwagens 17 via a linkage 18, 18 ', 18 "with a pendulum grinder 19 is pivoted, which is mounted on a shaft 20. The linkage 18, 18 ', 18 "and the shaft 20 are used in a more conventional manner Way, other functions of the machine. In the present case, only the arrangement is new of the pendulum sander 19, which includes a printed circuit 21, which is not shown Contact springs is scanned so that two tracks are always energized at the same time (see Fig. 8 and 9).

The pendulum loop he 19 has the effect that with further advancing point when keying in the to be tested Number of other crossing points of the matrix 3 are controlled, with the multiplication of the matrix 3 each keyed in digit is carried out with the assigned digit weight.

To explain the matrix 3, reference is made to FIG. 10 referenced. The lower row of numbers AA shows the position of the adjusting pin carriage 17, that is, the point. The weights BB , as indicated in the top line, are now assigned to the positions of the adjusting pin carriage 17. It should be noted that the weight 5 is assigned to position 5 of the setting pin carriage - but that the weight 10 is assigned to position 6 of the setting pin carriage and from then on it goes down. The series of numbers CC correspond to the digits 1 to 9 and the "zero", whereby the zero is assigned the number 10, since otherwise the zero could not be differentiated positionally because the multiplication with each weight results in zero again. The remainders of the multiplication of the digits by the weights for the modulus 11 are now entered in the matrix 3. Keying in the "2" in the first position results in the remainder 11 - 2 = 9, keying in the "2" in the third position results in the remainder 11 - 2X3 = 5, and pressing in the "2" in the sixth position results in the Remainder 22 - 2 X 10 = 2, since the sixth digit is assigned the weight 10; the modulus 11 is doubled or further multiplied to calculate the remainder in the event that the number is greater than 11 or greater than a multiple of 11.

If one now looks at the residual values obtained and divides the matrix into four square fields a, b, c, d , one can see that field a is mirror-inverted with field d, that is, each in field α from top to bottom The row read below reappears in field d in the same order, read from bottom to top, and that field b is a mirror image of field c in a similar way. Furthermore, the columns of the residues in the first five rows read from top to bottom are the same as the columns in the second five rows read from bottom to top. This fact can also be expressed in such a way that each residual value of the first row adds eleven to each residual value of the sixth row that is on the same line. The same applies to each residual value of the second with each residual value of the seventh row, for each residual value of the third with each of the eighth, for each residual value of the fourth with each of the ninth and for each residual value of the fifth with each of the tenth row. However, since 11 is the modulus, the same result is obtained if a number in the first row is counted as positive, but counted as negative in the sixth row, and so on. You can move column c, d over column a, b and Connect digit 1 with digit 6, digit 2 with digit 7, digit 3 with digit 8, digit 4 with digit 9 and digit 5 with digit 10, provided that the residual values of the digits 6 to 10 are counted negatively. Can one also use the field? Slide over field b for reasons of symmetry if the digits 1 to 5 assigned to field α are counted as negative and digits 6 to 10 assigned to field b are counted as positive. Of course, you could have done the other way around and shifted the field b over the field α . This would have been less favorable, however, since the field α contains the number 7 several times. Is it cheaper, the digit? count as negative 4. Since field b does not contain a "7", this counting method is extremely favorable for a binary electronic computing device, since only the number 7 as the only value would require three pulses to a basic memory 1, 2, 4 and 8 in the electronic counter.

This surprising number system thus enables the required 100 intersection points of the matrix to be reduced to only 25 intersection points. Semiconductor diodes 22 are arranged on these, as shown in FIG. The semiconductor diodes are connected to the electronic computing device 4 known per se via the numeric contacts 15 and the tapping points q, r, s, t, u in such a way that they add the value assigned to the corresponding semiconductor diodes and shown in the diagram in FIGS or subtracted, depending on the direction of the pulse traveling over the lines.

The pendulum grinder 19 has five sliding tracks a to e, each of which is interrupted at two points. The "positive" direction is preselected at one interruption and the "negative" direction at the other for the pulse to pass through. These sliding tracks are connected to the "ordinate strands" of the matrix 3, as shown in FIG. 9 can be seen. In the first place, accordingly through which the slideway α bridging contact the ordinate α for the passage of the selected pulse. If, for example, button 3 is now pressed, the diode 11 is activated, since all the other diodes, with the exception of diode 11, receive the same pulse as a counter voltage. However, according to the scheme shown in FIG. 10 and due to the negative passage of the pulse, the diode 11 causes a subtraction by 3, which, in view of the modulus II, is equivalent to an addition by 8.

The pulse driving the corresponding diode of the matrix 3 is activated by a microswitch 23 (F i g. 2), which is supplied by a shift rod 24

ίο

is acted upon when the adjusting pin carriage 17 is moved further. The blocking of the machine in all Cases in which a remainder remains in the electronic arithmetic unit 4 is carried out by a Locking magnets 25 in the FIG. 6 and 7 illustrated manner. According to FIG. 6 is located the machine is in the locked position, the connection to the locking magnet 25 by the Control lever 26 has been interrupted, d. i.e., a ma-

can be used. The decadal system is then replaced by a higher order system, provided that that one does not have several letters together to have the same count in the electronic Wants to assign computing device.

A particular advantage of the device according to the invention is that, despite use an electronic computer, which in binary Be

drove only four basic memories, namely the machine rotation cannot take place because the digits 1, 2, 4 and 8 have a large capacity Keyed in sequence of digits turned out to be incorrect - at least ten digits can be reached, has sen. Of course, this does not exclude that account

The F i g. 7, on the other hand, shows the machine in which numbers can be checked that are more than ten Approval position, where the keyed-in sequence of digits have digits, provided that the associated proved correct. The blocking magnet 25 in the mother machine has such a capacity. Man acts here as a result of a surge of current then repeatedly z. B. in the eleventh position the first the electronic computing device 4 under the position in the twelfth, the second, etc., in particular, Pressure of the locking pin 25 'causes the incorrect number swap over ten to be pivoted

Control lever 26 in the direction of the arrow, the latter by means of the axle bolt 27 on the machine side wall 28 is movably mounted. At the same time pushes the rear part of the control lever 26 with the one attached to it Surface 29 on the bolt 30 of the engaging plunger 31, which is mounted on the bolt 32, wherein

the latter attached in the engagement lever 33 and also deliver 25 results. Til (h Fi 6) il d Ah

Places are very rare.

If necessary, a number other than "eleven" could be used as the modulus. Included Prime numbers are particularly suitable as moduli, since then, as is known, corresponding arithmetic operations can be carried out, which verifiable Er

on the lower part (see also Fig. 6) by means of the axis 34 is arranged rotatably in the machine side wall 28. On the upper part of the engagement lever 33, the machine engagement axis 35 is mounted, the b ih bk d dl ih h

For the blocking of the blocking magnet 25 can an additional, e.g. B. be provided by a lock secured switch.

In the case of parent machines of the type shown in FIG. 1 shown i i

g g g

of the type which is known per se and is therefore not described in more detail and which has a wider carriage 31 Lever connections, for example, from the '"" "

Written lever connections are actuated, for example, from the function key 36, 8 (see also Fig. 1, 2) will. The engagement tappet 31 has a bent tab 37, which together with the Verschwenihb i.e.

especially if this can be tabulated, an additional switch (not shown) can be used for this Care must be taken that the account number check and the blocking by the blocking magnet

The engagement of the engagement lever 33 and the machine 35 25 only comes about when a certain engagement axis 35 strikes against a catch pawl 38. Column of an accounting document 32 is written then the account number, if a link lever 40 angeord- pivotally test only when the transcript of the account number is net. This carries at the lower end a bolt _z. B. a customer account, suppliers, accounts or 41 which turns in a slot 42 of a tie rod 43 40 L account , while it grips when the entry is made and the coupling gaps are omitted via a coupling pawl 44.

ment 45 to the main drive, not shown, it continues to cause no difficulties

Machine releases. to train electronic computing device 4 so that

The pendulum grinder 19 can carry a further grinding track that each shows the remainder of it, which is used to switch off the electronic device 4. For this purpose, in which the arithmetic operations are performed by transversal, a so-called "overtravel position" can be provided according to the invention. When jumping back
of the adjusting pin carriage 17, for. B. when pressing a
Function key 8, the pendulum grinder comes briefly 50
early in its overtravel position; there is a
Slideway closed, resulting in the shutdown of the
electronic arithmetic unit device 4 causes.

be checked or if only the additional numbers, which the account numbers are verifiable make, should be determined.

In the case of shaking and jumping cart machines with automatic function control, the aforementioned additional switch, just like on regular machines, the test device only can be set to function with the tab key.

The pendulum grinder 19 then rebounds into its zero position return. The next time a key is pressed 55 all function keys, for example an adding power The control pin carriage 17 is already a first machine, despite the additional service Half step, whereby the electronic computing device 4 is switched on again.

For an overview and simultaneous control, li d

the number checker their normal actuation force and actuation direction, so that disadvantageous tilting

gg movements do not occur here. Is essential

in addition or instead of the blocking magnet 25 in 60 also that any voltage fluctuations do not light up a lamp in every carriage position, which have an influence on the function of the test device, the electronic number test is provided.
The lamp goes out when a verifiable combination of digits is keyed in.

It is understood that the test device according to the invention in a corresponding adaptation for Data processing machines of various types - including those that register letters -

Claims (18)

Patent claims: 1. Test device for multi-digit numbers, each with an additional digit or an additional number have been made verifiable which latter from a scheme of the multiplication of the individual 709 508/143 NEN digits of the number to be checked with weights characteristic of the various positions and a checksum or some other addition of the intermediate results is, characterized in that a ten-key field (5) in which the to be tested Number is keyed in places, key contacts (15) and one that depends on the place Circuit (19) are assigned and that the key contacts (15) and the circuit (19) during or immediately after a digit is keyed in, where a Intermediate result is stored in an evaluation and storage device (4), which immediately with or after keying in the last digit of the number to be checked a display above delivers the result of the test or the one machine to which the test device is assigned is, enables or blocks. 2. Test device according to claim 1, characterized in that the multiplication of the Digits with the weights is carried out by a multiplication circuit in which the pre-calculated Intermediate results or their values reduced by a certain modulus in the form of crossing points depending on the pressed key (Γ) and the corresponding one Position can be controlled. 3. Test device according to claim 2, characterized in that the multiplication circuit is formed by a matrix (3), which consists of a grid of intersecting ordinates and There is abscissa, with semiconductor diodes (22) arranged at the intersection points are, which can assume at least two different switching positions, and that the matrix (3) connected to the individual key contacts (15) and to the circuit dependent on the position is. 4. Test device according to claim 1 or one of the following, characterized in that the location dependent electronic pulsing from one with a printed circuit board (21) provided pendulum grinder (19) is formed during the successive keying of the digits of the number to be tested moved over the link chain (17, 18, 18 ', 18 ") or is pivoted. 5. Test device according to claim 1 or one of the following for machines in which a Valuables, e.g. B. an adjusting pin carriage (17) is provided, which has the numerical value of each pressed Picks up a key and continues to press each time a key is pressed, characterized by that the conductor element is coupled in a motion-locked manner to the actuating pin carriage (17), in such a way that the fixed and the conductor element sensing contacts through the printed circuit (21) with each advancement of the actuating pin carriage (17) another electrical connection between each other, with the button contacts (15) and obtained with the matrix (3). 6. Test device according to claim 1 or one of the following, characterized in that the Conductor element is designed in the form of a pendulum slider (19) which is pivoted. 7. Test device according to claim 1 or one of the following, characterized in that the the conductor element, in particular the pendulum wiper (19), on the one hand with scanning contacts the matrix (3) and on the other hand with the key contacts (15) are connected. 8. Test device according to claim 1 or one of the following, characterized in that the Evaluation and storage device ordered from an electronic computing device (4). 9. Test device according to claim 1 or one of the following, characterized in that the electronic computing device (4) with those located at the intersection points of the matrix (3) Switching elements is connected, each of the switching elements being assigned a specific numerical value is what the computing device in the passage of the pulse at or during pressing the button (T) is added. 10. Test device according to claim 1 or one of the following, characterized in that that the matrix (3) is matched to a prime number checking system, preferably to a Her system, ten different weights are assigned to the digits, omitting the zero. 11. Test device according to claim 1 or one of the following, characterized in that that the z. B. in the Her system in and of itself having 100 crossing points matrix (3) once as a mirror image to at least half, but preferably twice as a mirror image a quarter, e.g. B. to 25 crossing points, is reduced by one half of the spot weights an addition and the other half a subtraction in the electronic computing device (4) is assigned and / or by one half of the digits, e.g. B. the numbers 1 to 5, an addition and the other half, e.g. B. the digits 6 to 0, a subtraction in the electronic Computing device (4) is assigned. 12. Test device according to claim 1 or one of the following, characterized in that that the switching elements in the crossing points of the matrix diodes, in particular semiconductor diodes (22) are. 13. Test device according to claim 1 or one of the following, characterized in that that the printed circuit (21) carrying the conductor element, in particular the pendulum wiper (19), has an overtravel position into which it briefly moves when the adjusting pin carriage (17) returns arrives, wherein the electronic computing device (4) is switched off, and from which it automatically rebounds to the zero position. 14. Test device according to claim 1 or one of the following, characterized in that that the pendulum sander (19) when the first button (Γ) is pressed from its zero position via the Link chain (17, 18, 18 ', 18 ") is pivoted into the position assigned to the first point, wherein the electronic computing device (4) is switched on, so that this at the end of the Stroke of the key impression already carries out the first addition or subtraction. 15. Test device according to claim 1 or one of the following, characterized in that that the matrix (3) and the electronic computing device (4) housed in a flat base (2) are on which the machine (1), I 234 to which the test device is assigned, placed or connected to the machine to form a unit can be. 16. Test device according to claim 1 or one of the following, characterized in that that the current over the matrix (3) and the count in the electronic computing device (4) the effecting pulse is generated by a microswitch (23), which reacts to the movement of the Place the advancing link of the machine, e.g. B. the adjusting pin carriage (17) or switch lock, appeals to. 17. Test device according to claim 1 or one of the following, characterized in that that one on the machine engagement axis (35) of an adding machine or on another when loading actuation of the function keys (8) inevitably moving member acting blocking magnet (25) provided is, which triggers all function keys of the machine (1), which the test device is assigned, blocks as long as the electronic computing device (4) does not Release z. B. caused by attraction of the locking magnet (25). 18. Test device according to claim 1 or one of the following, characterized in that that the key contacts each consist of a contact ring (13) consist of a contact spring (14) against a contact (15) of a preferably designed in the form of a printed circuit Printed circuit board (9) and lifted off when the button (T) is pressed. In addition 3 sheets of drawings 709 508/143 1.67 © Bundesdruckerei Berlin