US 3860807 A
A completely electronic taximeter has a first storage which has sufficient capacity for storing all variables required for calculating an individual fare and for storing totals required for determining the payment of the taxi driver. During operation of the taximeter the variables referring to the individual fare are transferred from the first storage to a buffer storage. Synchronizing means transfer the contents of the buffer storage in sequence to corresponding indicator elements. Although each indicator element is energized only briefly the repetition rate is sufficiently high to cause a constant visual indication. The capacity of the buffer storage is only large enough to store the values required for such indicator.
Claims available in
Description (OCR text may contain errors)
D United States Patent 1 91 1111 3,860,807
Fichter et al. 1 Jan. 14, 1975 ELECTRONIC TAXIMETER HAVING 3,512,706 5/1970 Bruce-Sanders 235/30 R SERIALLY ENERGI'ZED INDICATOR 3,544,971 12/1970 Looschen 340/1725 MEANS 3,641,330 2/1972 Hatano et al. 235/159 4 3,698,627 /1972 Kelch 235/ R Inventors: Manfred Fichter, Weiler; Siegfried 3.703.985 11/1972 Berg 235/30 R Spauszus, Villingen; Ulrich 3,749,896 7/1973 Munt 235/152 Warkentin, Tannheim, all of Germany Primary ExaminerEugene G. Botz Assistant ExaminerDavid H. Malzahn  Asslgnee: l l Apparate GmbH Attorney, Agent, or Firm-Michael S. Striker V1ll1ngen/Schwarzwald, Germany  Filed: Jan. 19, 1973  ABSTRACT A completely electronic taximeter has a first storage 21 A l. N 1 pp 0 323,907 wh1ch has sufficient capaclty for storing all varlables required for calculating an individual fare and for stor-  Foreign Application Priority Data ing totals required for determining the payment of the Jan. 21, 1972 Germany 2202865 taxi driver- During Operation of the taximeter the variables referring to the individual fare are transferred  U.S. C1 235/168, 235/30 R, 340/1725 from the first storage to a buffer storage. Synchroniz-  Int. Cl. G07b 13/04 g means transfer the Contents of the buffer Storage  Field of Search 235/168, 156, 30 R; in sequence to rr sp nding indi ator elements. Al-
- 340/1725 though each indicator element is energized only briefly the repetition rate is sufficiently high to cause a  References Cited constant visual indication. The capacity of the buffer UNITED STATES PATENTS storage is only large enough to store the values re- 3,35s,125 12/1967 Rinaldi 235 92 (Med for Such mdlcator' 3,492,656 l/l970 Hildebrandt 340/ 172.5 5 Claims, 7 Drawing Figures 14 15, 7 [111 151] I 139] 12'\.g Storage 1., m
k 2 Indicator 1 3 5 Constant Furnishing Means Constant Generation Address Decoder 1 I 20 19 2 9 l Stor- 0 Comx a a :3 l: l 25 *5; age puter l0 5 a a U l E z 5: 18 l E3 16 Selector 6 Control Circuit 8 Pulse Sequence 1 6 Selector Dis ance Pulse Waiting G Time Pulse Gen.
2 lndicofor 5 Constant Furnishing Means sum 10F 7 Add res; Decoder Constunf Generation 16 Selector C E U U U 5 U U U muouwm v Buffer Storage PMENIE JAN w 4 1975 l u uwymmmwm 2 0 v mw l o. u C D. r
e w 9 S a uwflcsou Waiting Time Pulse Gen.
Pulse Sequence Selector PAIEMEU 3.860.807
SHEET 20F 7 Decoder QFIG.2
Fair Indicator ,14 l v I I Decade r Buffer Storage 1 Fl1G.3
Decoder Extras And Total Indicator Counter PmmE JAmmvs, 3,860.80?
SHEET 5 OF 7 Storage 9 Counter FIGA' mamm w 3,860,807 sum 60F 7 FIG. 5
Shift Register PATENTEDMN1 M915 7 3,860,807
SHEET 7 BF 7 Indicator 5 14 I 15 Consfo nf D der b1 Z Generator Decoder Buffer l S forog e Corhputer And Storage Means Reg is'rer 6 Control 0kt. 8
ster ifr R Pulse e5 93 v 910 Sequence Selector ELECTRONICTAXIMETER HAVING SERIALLY ENERGIZED INDICATOR MEANS BACKGROUND OF THE INVENTION This invention relates to electronic taximeters. Specifically it relates to electronic taximeters wherein measuring elements furnish pulse sequences, as a function of the distance travelled and the waiting time incurred. Pulse sequences separately or in combination are then used to compute the fare. The computation is carried out by a computer and storage means.
In known electronic taximeters the pulses signifying waiting time and the pulse sequence signifying distance travelled are applied to a circuit which selects only the faster pulse sequence for determining the fare. A countdown device is then furnished following the above-mentioned selector circuit, to furnish output pulses for a given number of input pulses, that is the fare rate is taken into consideration. The output pulses may then be applied to a mechanical or electronic indicator means.
In another known arrangement, a. binary counter serves to countdown the pulses as mentioned above and an electronic indicator is mentioned. Further, two individual counters are furnished, one of which is constantly connected to the indicator means and may be reset, while the other operates continuously and is not reset until a certain key is activated. The latter counter serves to furnish an indication of the total fare collected, for example during the day. After the abovementioned key has been activated, this total is transferred to the indicator and the account in the counter is extinguished.
In the first above-mentioned embodiment, the total values are stored in mechanical counters. These additional mechanical counters require additional expense which makes such taximeters economically unfeasible. However, of course, such totals must be available in order that the pay of the taxi driver may be correctly determined.
In the second above-mentioned known arrangement, there is no mention made as to how other totals are being stored. Probably mechanical counters are also considered here.
SUMMARY OF THE INVENTION In a taximeter in accordance with the present invention, measuring elements furnish pulse sequences indicative of the distance travelled and the'elapsed waiting time. A computer and storage means has a storage which has acapacity sufficient for storing all variables required for computing the individual fares, and further for computing totals required for determining the pay of the taxi driver. An electronic indicator means is furnished which is connected to the above-mentioned storage through a buffer storage, the capacity of the buffer storage corresponding to the capacity of the indicator means. The indicator means has a plurality of indicator elements. While the taxi is in operation, synchronizing means transfer the contents of buffer storage locations sequentially to corresponding indicator elements.
In accordance with a preferred embodiment of the present invention, the indicator means are divided into a first and second portion. The first portion serves to indicate the fare while the taximeter is in operation, while the second portion serves to indicate the additional charges incurred under the same conditions. When the taximeter is not operative, selector elements areavailable which, upon activation, cause the transfer of selected totals from the storage of the storage and computer means, through the buffer storage and into the indicator means.
The above-described arrangement has the advantage relative to the known arrangements that only one indicator means is required for indicating both the individual fare values and the final totals. Further, due to the fact that each indicator element is only briefly activated during each cycle, relatively little power loss is incurred in the indicator means.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a generalized block diagram showing a taximeter in accordance with the present invention;
FIGS. 2 and 2a is a circuit diagram of the constant furnishing means;
FIG. 3 is a circuit diagram of the indicator means, including associated storage means in block diagram form;
FIG. 4 is a more detailed block diagram of the computer and storage means;
FIG. 5 is a more detailed block diagram of the measuring means; and
FIG. 6 is an additional block diagram of the overall taximeter, as embodied in a highly integrated circuit form.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the invention will now be described with reference to the drawings.
The major components of the electronic taximeter are shown in block diagram form in FIG. 1. The taximeter comprises a computer and storage means 1, an indicator means 2, control circuit means 3, switching circuit means 4' for controlling the input and output operations. and an external constant furnishing means 5 which furnishes constants corresponding to and derivable from predetermined fare rates.
The control circuit means 3 comprise input register 6 which is connected to input lines ele6 (FIGS. 1 5). Input line el receives a pulse sequence which corresponds to the pulse sequence signifying the waiting time or the distance travelled, depending upon which has the higher rate. The pulses signifying the actual distance travelled are received on input line e The pulses In accordance with a first fare rate the distance increment may correspond to 200 meters.
In accordance with a second fare rate the distance increment may be 150 meters.
In accordance with a third fare rate the distance increment is 100 meters, while in accordance with a fourth fare rate the distance increment is 50 meters.
In order to achieve a particularly exact measurement, it is desirable that, at each fare rate, the particular distance increment is represented by the same number of pulses. Thus, for example, 1,200 impulses may be generated for each distance increment. Thus, for the first fare rate, six pulses are generated per meter, for the second fare rate, eight pulses are generated per meter travelled, for the third fare rate, twelve pulses per meter, and for the fourth fare rate, 24 pulses per meter.
The photoelectric measuring means, if the shaft is driven in such a manner that one rotation corresponds to one meter travelled, has disks having six holes for the first fare rate, eight holes for the second fare rate, 12 holes for the third fare rate and 24 holes for the fourth fare rate. Under these conditions, any pulse received at the input on line e would directly signify a predetermined fare.
Instead of the arrangement mentioned above, the pulses at the input e may correspond only to a particular distance travelled. Under these conditions one pulse may for example signify one-tenth of a meter travelled. In this case the fare increase must be computed by applying constants corresponding to the desired fare rate when computing the fare as a function of the pulses on line e This is the situation which will be described herein, since it constitutes the preferred embodiment of the present invention.
The pulses received on line e, are pulses selected by the circuit 7 which furnishes the pulse sequence corresponding to the time or distance pulse sequence which has the greatest rate. This circuit will be described in greater detail with reference to FIG. 5. The pulses received on line e signify the distance travelled, whether the taxi is or is not occupied. It must be noted that the total distance travelled must be available to the taxi drivers employer. This value is normally indicated in mechanical taximeters in a separate counter which counts the total number of kilometers travelled by the taxi. The mechanical taximeters of course also have indicators which indicate the total distance travelled by the taxi in an occupied, that is in a passenger carrying mode. Thus, for example, it may be desirable to apply one pulse to line e for each 100 meters travelled by the taxi. This may be accomplished externally by counting down the pulses applied to line e Alternatively, it may be done internally within the taximeter in such a manner that for each 1,000 pulses which are applied at input e one pulse is applied to input e Timing pulses which indicate waiting time to be charged to the passenger are received on line e This line is connected to a timing pulse generator, for example an oscillator which has a frequency of 1 KHz. It should be noted that the so-received timing pulses are not applied directly to stage 7, but are first modified by the control circuit 3 in accordance with constants furnished by the constant furnishing means 5. Thus the charge for the waiting time, too, may be adjusted in accordance with predetermined fare rates.
Synchronizing pulses are received on line e which are also derived from an electronic oscillator. The synchronizing means furnish the synchronizing pulses which may have a frequency of anywhere from KHz to a MHz and which serve to synchronize the whole taximeter system. The synchronizing pulses are fed into a shift register 8.
The computer and storage means 1 comprise the storage means 9 and the computer means 10 which will be described in detail with reference to FIG. 3. The indicator means 2 comprise, in the main, a buffer storage 11, a counter 12, a decoding arrangement 13 and two separate indicator sections 14 and 15. The construction and functioning of the indicator 2 will be described in detail with reference to FIG. 3.
Block 4 of FIG. 1 comprises manually activatable switching circuit which comprises an input keyboard 16 having keys for initiating input and output operations. Specifically, keys 17 function for input operations as for example taxi unoccupied, fare rate 1, fare rate 2, fare rate 3, fare rate 4, cash, and additional charge, while keys 18 control the output operations as for example to initiate the indication of the total distance travelled with taxi occupied, total distance travelled occupied or otherwise, etc. Keys 17 and 18 activate contacts which are coded in a matrix 19 which may for example be a diode matrix. The output of the matrix may be a 4-bit binary code which furnishes signals which are stored in a register 20. The contents of register 20 may be transfered to control circuit 3 when required. Of course it goes without saying that instead of the keys shown, input and output operations may be initiated by other switching circuit means, as for example rotary switches. Such rotary switches would initiate the different functions in accordance with the angular positions thereof. Thus for example a first rotary switch may be used to replace keys 17 while a second rotary switch may be used to replace keys 18.
FIGS. 2 and 2a show the circuit diagram of the constant furnishing means. The constant furnishing means has a constant furnishing input receiving address signals on lines a a Lines il -(l are the output lines of a counter 25 which also controls the addressing of the first storage means, namely storage 9 of FIG. 1. The code combination which appears at the output of counter 25 energizes selected ones of lines a,a This is applied to a decoding arrangement 21 whose output is furnished on lines e00-e45. Specifically, lines e00- e45 are energized sequentially within each cycle of operation of the taximeter. The output of the constant furnishing means is supplied on lines i -i These constants are applied to the computer and storage means. The constant furnishing means comprise printed circuit cards 22 and 23 which are interchangeable and may have any desired configuration. For example the connections between input lines e00 to e,, and the output lines i -i may be made by solder joints, diodes, screw connections, etc.
A preferred embodiment of the constant furnishing means will now be described with reference to FIGS. 2 and 2a.
As is shown in FIGS. 2 and 2a a plurality of AND- gates Ul0-U, have inputs connected to input lines e0- 0-e, and output lines connected to decimal coded lines Z0-Z9. It should be noted that not all input lines e have an AND-gate connected to them. For example, lines e43-e45 are directly connected to the decimal coded lines. The output lines of AND-gates UIOUI6 are labelled dl-d7 respectively, the output lines of AND- gates U17-U20 are labelled vl-v4 respectively, the output lines of AND-gates U21-U24 are labelled wl-w4, respectively, the output lines of AND-gates U25-U28 are labelled xl-x4, respectively, the output lines of AND-gates U29-U32 are labelled yl-y4, respectively, while the outupt lines of AND-gates U3- 3-U36 are labelled d8-dll, respectively. The abovementioned output lines of the AND-gates are arranged in a vertical direction and therefore intersect the decimal coded lines Z0 Z9 which extend in a horizontal direction. At desired points of intersection, an electrical connection is made, for example, by soldering as mentioned above. Alternatively, the output lines of' the AND-gates may be on the frontside of the circuit board, while thedecimal coded lines may be on the rear side of the circuit board and holes are provided in the circuit board at the point of intersection. The desired connections are then made by means of scres. Once such a connection has been established, energization of one of the output lines of AND-gates results in a corresponding energization of one of the decimal coded lines. Further, a decoding arrangement 24 is situated on the circuit board 22. This converts the oneout-of-ten coding existing on the decimal coded lines to a 4-bit binary code. The output of the decoder 24, namely the constant in a 4-bit binary code, is then connected to the computer means 10. Further shown in FIG. 2 is a flip-flop FF10 which may be in a OI or a 10 state. The two flip-flop states correspond, respectively, to the condition of fare I and fare II in the taximeter. These terms will be explained'in more detail below. It should only be noted here that when flip-flop FF10 is in the IO state, AND-gates U10-U14, as well as AND-gates U33-36 are in a conductive state, while, when flip-flop FF10 is in the OI state, AND-gates U and U16 are conductive. Thus when inputs e00-e,, are
activated in turn by the decoder 21, the corresponding AND-gates furnish a signal at the corresponding AND- gate output line, which signals are transmitted, as described above to the decimal coded lines Z0-Z9. A corresponding constant thus appears on lines i i It should further be noted that on circuit board 23, AND-gates U17-U32 are further energized in dependence upon four conducting lines t -t These conducting lines are externally connected to keys l7, and, specifically, to keys T1, T2, T3 and T4 which, individually, indicate fare rates 1, 2, 3, and 4. Conducting line 1 is connected to one input each of AND-gates U17 to U20, conducting line t is connected to one input of each of AND-gates U21-U24, conducting line t is connected to one input each of AND-gates U25-U28, conducting line r is connected to one input each of AND- gates U29-U32. As shown in FIGS. 2 and 2a, the second inputs of AND-gates U17-U32 are connected to the outputs e05, e06, e07 and e08 of the decoder 21. Thus as soon as T1 is closed, AND-gates U17-U20 become conductiveand, upon activation of lines e05 to e08 by the decoder 21 furnish pulses sequentially to the decimal coded lines Z0 to Z9 in accordance with the connections previously made. AND-gates U21 to U24, U25 to U28 and U29 to U32 are also connected to conductors e05 to e08. Thus conducting lines v -v carry the pulses for fare rate 1, lines w1w4 carry the pulses for fare rate 2, lines XII-x4 the pulses for fare rate 3 and lines y1- y4 the pulses for fare rate 4. Since four separate fare rates are not required in a great many taximeters, the printed circuit plate 23 may be limited to, for
example, only lines v1v4 if only one fare rate is to be implemented, or lines vl-v4 and w1-w4 if two fare rates are required. This is also the reason why part of the circuitry is on a separate printed circuit board, namely printed circuit board 23.
A'discussion of at least part of the constants which are furnished by printed circuit boards 22 and 23 will now follow. The number and type of constants can change with the fare rate. For example, one of the constants is the base fare, that is the fare which is indicated on the taximeter as soon as it is put into operation. This is the fare which each passenger must pay. independent of the actual distance travelled. Let it be assumed that this constant, namely the base fare, is to be supplied via lines e00 to e04. Further, let it be assumed that this base fare is $1.25. During each operating cycle of the taximeter, pulses are applied to lines al to a6 which, in their combination, serve to energize input lines e00 to e04 sequentially. When line e00 is energized, a pulse is furnished through AND-gate U10, line d1 and line Z5 which causes the output of decoder 24 to furnish the following pulse combination:
i1=l i2=0 i3=l i4=O When this 5, which corresponds to the last place in the base fare of $1.25, has been processed, the input e01 is energized by a corresponding pulse combination on lines a1-a6. As a result of energization of line e01, AND-gate U11 furnishes a pulse to line d2 which, via line Z2 causes the following pulse combination to appear at the output of decoder 24:
il=0 i2=l i3=0 i4=0 After this value, which corresponds to the 2 in the base fare of $1.25, has been processed, the numeral 1 is similarly processed by energization of line e02.
Energization of lines e03 and e04 causes corresponding zero values to appear at the output of decoder 24, that is lines i,-'i all carry zeros. This of course is due to the fact that only three digits are contained in the base fare. It should be noted that for the above operation to take place, flip-flop FF10 must be in the [0 state. Flipflop FF10 in actual practice is a part of the control circuit 3 and has been added to the constant furnishing means of FIG. 2 only for purposes of clarity.
The reason for the different states of flip-flop FF10 will now be explained. Flip-flop FF10 is in the IQ state when the base fare is being indicated on the indicator means, but when the distance or waiting time which is paid for by the base fare has not yet expired; flip-flop FF10 is in the O1 condition, after the service rendered to the passenger, is equal to the base fare. Thus, when the flip-flop is in the OI state, the normal advance of the indicator corresponding to the fare rate in force has to take place.
It might be noted here in addition that the base rate is actually an equivalent of the increment required to advance the taximeter. For example, to remain with the given example, the base rate of $1.25 may be equal to the fare increment which is, for example, based on a 200 meter distance for a 20 second waiting time or a mixture of both. However, it is equally possible, that the base rate is the equivalent of an integral multiple of the fare increment or a fraction thereof. For example,
the indicated fare may advance in steps of $0.25. The base rate of $1.25 is to pay for a distance travelled of 500 meters or an equivalent waiting time. Then the base rate covers a distance equal to two and one-half times the distance for a fare increment or the equivalent waiting time. The distance equivalent to the base fare (500 meters in the above example) is normally referred to as the initial distance, even though, as explained above, not only an initial distance but a corresponding waiting time may be involved.
In order to take account of all these factors, it is necessary that constants be furnished which correspond to the base rate, to the distance increment for which the fare is advanced under normal conditions and for the initial distance, that is the distance which is paid for by the payment of the base fare.
Thus the base fare is first entered through lines e to e04 and the individual fare increments are then also transmitted by energizing these lines, so that the total fare comprises the base fare in addition to the fare increments. After the taxi has rendered a service corresponding to the base fare, flip-flop FF10 is switched to the 01 state causing AND-gates U15 and U16 to become conductive. The other inputs of AND-gates U15 and U16 are connected to lines e00 and e01 respectively. Thus the fare increments are transmitted via lines e00 and e01 after flip-flop FF10 has changed its state. Thus, in the example shown in FIGS. 2 and 2a,
a sequential energization of lines e00 and e01 when flip-flop FF10 is in the second state, causes the constant of $0.25 to appear on output lines il-i4. Thus lines e00 to e04 are used twice, that is first to furnish the constant corresponding to the base fare and later to furnish the constant signifying the value of the fare increment.
Output lines e05 to e08 of the decoder 21 are also utilized more than once, as is evident with the description of the printed circuit board 23 which is given above. Each line e05 to e08 allows the specification of one numeral for each fare rate T1 to T4. These fare rates may be the following:
Fare rate If the number of pulses is reduced by a factor of 100 to 1 either previously or after the constant is furnished, then fare rate 1 corresponds to a pulse reduction rate of 20 to l, fare rate 2 to a pulse reduction rate of 15 to l, fare rate 3 to a pulse reduction rate of 10 to 1 and fare rate 4 to a pulse reduction rate of 5 to l.
The connections between the vertical conducting lines vl to v4 and the horizontal lines Z0 to Z9 on printed circuit board 23 are indicated by the circle.
A further constant, which has been defined above, is in the initial distance. This, too, must be furnished by constant furnishing means 5. For this purpose lines e09 to lines e12 are energized and furnish, over AND-gates U33 to U35 and lines d8 to dll the number 250, at the output of the constant furnishing means. As previously explained, this number corresponds to the initial distance.
A further constant which must be furnished by constant furnishing means 5, is the constant required for stepping down the repetition rate of the waiting time pulses. This is furnished by energization of lines e43 to e45. As will be explained is more detail later on, the pulses which are supplied on line e3 must be reduced in frequency by a ratio of 10 to 1. Under these conditions, 200 meters of travelled distance correspond to a waiting time increment of 20 seconds, if the oscillator which furnishes the timing pulses operates at 1,000 Hz.
A further constant which also must be supplied by printed circuit board 22 is the additional charge, that is the amount which must be added to the portion of the indicator means indicating additional charge upon activation of the corresponding key 17. This takes place when'one of the lines e00 to e, is energized, but will only be explained in more detail later on with rela tion to the organization of storage 9.
To summarize, the constant furnishing means, which are exchangeable and externally available, comprise the decoding arrangement 21, which converts the signals which are furnished by lines a] to a6 into the sequential energization of lines e00 to e in a predetermined order. This energization in turn results in predetermined constants appearing in a predetermined order at the output of the constant furnishing means, namely on lines il-i4. These constant values are then supplied into the computer and storage means 1.
The indicator means 2 will now be described with reference to FIG. 3. Shown in FIG. 3 are a buffer storage 11, an address counter 12, which serves to address the individual storage locations, and a decoding arrangement 13 which comprises a first part 13 and a second part 13". Further, the indicator means comprise a first indicator section 14 and a second indicator section 15, each of which provide an indication of five numerals.
In the example shown in FIG. 3, the known type of sevensegment indicator is used, that is each numeral which is to be indicated comprises seven selectively energizable segments. Thus seven lines are required for the selective energization of a numeral in each indicator position. The seven lines are designated by bl to b7 respectively. Each of lines bl to b7 is connected with the same segments within each numeral cl to 010 of the indicator means 14 and 15. The decimal numerals cl to 05 constitute the indicator portion 15, while the decimal numerals 06 to 010 constitute the indicator portion 14. Indicator portion 14 serves to indicate the individual fares as long as the taximeter is operating. Indicator portion 15 serves a variety of purposes. While the taximeter is operating, that is while indicator 14 shows the current price or fare, indicator 15 shows the extra charges. When the taxi is standing still and when the taximeter is not operative, indicator portion 15 can be utilized to indicate various accumulated values as for example the total distance travelled while the taxi was occupied, the total distance travelled whether occupied or unoccupied, the total number of additional charges, the total number of fares transported, etc. Thus it is this portion of the indicator which is used to furnish all values which are required in order to effect an accounting between the fleet owner and the driver. These values are normally indicated by mechanical control counters in mechanical taximeters of conventional type.
The individual numerals cl to 010 are energized sequentially via lines d1 to through decoder 13". To summarize, the seven information bits which serve to energize the individual segments of numerals cl to e10 via lines b1 to b7 are furnished in parallel by the decoder 13' over lines hi to b7. However, the signals for the selection of the corresponding numerals 01 to 010 are serially supplied via lines d1 to d10. However, the energization of lines b1 to bl0 follows at such short intervals that, although pulses are applied to each numeral cl to 010 for only a short time interval the persistance of vision of the human eye causes the indicator to seem to be continuously energized. However, since the indicator is not continuously energized but constantly reenergized, it is required that the values to be indicated are stored in storage 11. This buffer storage may be a matrix having ten storage locations of four bits each, corresponding to the ten numerals c1 to e10. In order to address the storage for storing the data bits, the address counter 12 is provided which is a binary counter and which energizes the storage locations in sequence. For this purpose the output of counter 12 is connected to buffer storage 11 via lines fl-f4. These lines are also tied to the input of decoder 13 so that the correct decimal place cl to CIO of the indicator is selected simultaneously with the corresponding storage location in storage 11. The value stored in the storage locations of buffer storage 11 is transferred into the buffer storage via lines g1 to g4 which connect buffer storage 11 to storage 9 of the computer and storage means 1. Storage 9 is herein referred to as the first storage means. Normally, the connection is such that determined storage locations of storage 9 correspond to determined storage locations in buffer storage 11, so that any changes which occur in storage 9 are carried out simultaneously in storage 11. However, when one of the keys 18 is operated, that is when an output operation is to take place, the contents of storage 11, which normally comprise the individual fares and the additional charges of said individual fares, is destroyed and those values are entered which are present in the corresponding storage spaces for the total values in storage 9. These values are then transferred to the indicator 15.
A short explanation of the functioning of input register 6 as shown in FIG. 5 follows: this input register comprises eight flip-flops FFO to FFS each of which serves the function of an intermediate storage. Each of flipflops FFO to FF8 stores a value furnished by a corresponding measuring instrument until these values are called out by the translater portion of the control circuit 3 and transferred to the output stage comprising flip-flop FFO. From there the contents of the flip-flops are then processed in the remainder of the system. Flipflop FF] receives a pulse via line e6 as soon as the computing and storage means has determined that the indicator means have to be advanced. For example, in the example given above, flip-flop FFI is set as soon as, under fare rate 1, 2,000 distance or timing pulses have been counted and stored in the computer and storage means 1. Flip-flop FF] is thus not directly connected to the measuring instruments but receives its information from the computer and storage means via the control circuit 3.
Flip-flop FF2 serves to store individual pulses which might be either distance indicating pulses or waiting time indicating pulses, depending on which pulse sequence has the higher rate. These pulses are present at the output of a circuit 7 which, as previously stated, se-
- lects the pulse sequence having the higher rate. As
shown in FIG. 5 this is accomplished in the following way: First, all distance pulses which arrive at line e5 are used directly for setting flip-flop FF8. After these pulses have been reduced in rate in accordance with the tariff or fare rate in effect, they are applied via input e4 to flip-flop FF9 which is part of the abovementioned circuit 7. The timing pulses, also after reduction in rate if required in the computer and storage means, are applied via a line e7 for resetting flip-flop FF9. Line 27 is not only applied to the reset input of flip-flop FF9, but also to one input of an AND-gate U1 whose other input is the reset output of flip-flop FF9. This output thus carries a I signal after a timing pulse has been applied via line e7 to flip-flop FF9. Flip-flop FF9 is so constructed that the first timing pulse arriving over line e7 is used to flip the flip-flop from its [0" state to its "()I state/Only the second pulse arriving one line e7 is thus transmitted through AND-gate Ul so that AND-gate U1 furnishes a pulse to line el. Flipflop FF9 and AND-gate U1 thus together form the circuit 7 which, in itself is a known circuit and serves to select the higher one of the pulse sequences furnished on lines e4 and e7 to constitute the output applied to flip-flop FF2 through line e1.
A further flip-flop FF3 serves to store the 100 meter distance pulses. That is the pulseswhich are used in order to compose the total distance travelled by the taxi or the total distance travelled when in an occupied state. Again, the pulses applied to line e2 may be pulses whose rate is determined by the constant furnishing means 5 operating in conjunction with the computer and storage means 1. For example if the input constant of the computer 10 is 10 pulses per meter travelled, then the constant furnished must be 1,000, since 100 meters are equivalent to 1,000 pulses.
Flip-flop FF4 is set via line e8, when one of input keys 17 is activated to indicate an additional charge. Flipflop FFS is set via a line e9 as soon as the taximeter is put into operation through activation of one of the keys l7. Flip-flop FF6 is set through a signal on line e0, as soon as a fare or a distance travelled or a waiting time is reached wherein a change from one fare rate to another is to take place. It should be noted here that lines 26, e4, e7, e8, 29 and e0 each have an arrow which is to indicate that they are not actually connected with the external measuring elements, but derive their input signals from the computer and storage means 1, as soon as predetermined conditions are achieved. The only input lines which are directly connected to the measuring elements are lines 25 and e3, while line e2 can be selectively connected either to the measuring element or internally. The synchronizing pulses which, as mentioned above, are furnished via line e10, are entered in a multistage shift register 8 and serve to control the individual steps within the cycles of the computer and storage means through use of the control circuit 3. For each received synchronizing pulse, the shift register furnishes a synchronizing pulse over one of its output lines and thus controls the microsteps within the overall cycle.
Flip-flop FFO serves as the output flip-flop associated with the intermediate storage flip-flops FFl to FF8. At certain steps within the overall cycle, the condition of flip-flops FFl to FF8 is interrogated sequentially and if one of these flip-flops is set, its contents is transferred to flip-flop FFO. The signal is then further processed via the control circuit 3 and applied to the computer and storage means 1.
The computer and storage means will now be described in further detail. This will be done with reference to FIG. 4. As shown in FIG. 4 the storage 9 com- I prises 48 storage locations, that is it is capable of accommodating 48 numerals I in a binary coded form. Each storage location thus accepts four bits. An address counter 25 servesto address the different storage locations. Since this binary counter hassix stages, it is capable of counting from zero to 63. However, its counting capacity is limited to 48, so that after the 48th pulse, the counter is reset to 0. The counter is advanced via line k0, which also furnishes the pulses advancing counter 12 associated with storage 11. In response to each pulse received over line k0, the counter generates a 6-bit address which addresses storage 9, as mentioned above, via lines al to a6. The information in the so-selected storage location is then transferred to the computer means, and specifically to section 26 of a serial adder 26/27 and, if required, via lines g1 to g4 into storage 11.
The 47 storage locations in storage 9 are sufficient for storing all variables generated during the formation of the fare and further, generated during the formation of the various totals required for effecting the accounting between the fleet owner and the taxi driver. A possiblestorage layout is given in the following table: ,290
It will be noted that the storage locations a to a04 contain the fare during the individual ride, which fare comprises the base fare and the sum of the fare increments. Similarly, storage locations a05 to a08 carry the distance reduction rate corresponding to fare rate 1 to fare rate 4, while storage locations a09 to al2 furnish the constant for the initial distance while flip-flop FF10 is in its first state and furnish a pulse rate reduction of 100:1 when flip-flop FF10 is in the second state. Locations a17 to a37 are reserved for the storage of the total additional charges, the total distance travelled, the distance travelled while occupied, and the number of trips. These storage locations do not correspond to any constants furnished in the constant furnishing means 5, causing the corresponding output lines of the decoding arrangement 21 in constant furnishing means 5 to be disconnected.
Storage locations a43 to 1145 serve to store the timing pulses which arrive from the timing pulse generator via line e3. These pulses have a reduced rate corresponding to the constant furnished by constant furnishing means 5 prior to being applied to input e7 of circuit block 7.
In order to explain some of the above concepts more clearly, an example will be used. lt will be assumed that the waiting time increment, that is the waiting time which is to cause a fare increment, is seconds. Under conditions of fare rate 1 of the above-mentioned example this corresponds to a travelled distance of 200 meters. Thus for each pulse at the output of block 7 to have the same value relative to a fare increment, the distance increment pulses supplied at input 24 have undergone a pulse rate reduction of 20 to 1. Similarly, for. a timing pulse generator which generates 1,000 pulses per second, that is 20,000 pulses in 20 seconds, which corresponds to 2,000 distance increment pulses at fare rate 1. 1f the 100:1 rate reduction which will take place following stage 7 is taken into consideration, then the timing pulses must undergo a reduction of 1011-. Thus the pulses which arrive at input e3 are stored in storage location 1143 to a45. The pulses stored in these storage locations are then compared with the output of constant furnishing means 5 (outputs e43 to e45 of decoder 21) and a pulse is furnished to line e7 when the comparator shows that the number of pulses stored in locations a43-a45 is 10 pulses.
The computer means 10 comprise a first portion 26 and a second'portion 27 of a serial adder. Reference to the drawing shows that adder portions 26 accepts the signals from storage 9. For the pulse rate reduction mentioned above, it is seen that adder portion 26 furnishes signals to one input of comparator 28, while the other input of comparator 28 is connected to lines i,i which are the output lines of constant furnishing means 5. Comparator 28 thus continuously compares the number of pulses stored in storage 9 to the number of pulses required until a pulse of reduced rate is to be furnished at the output of comparator 29, namely on line kl. From line k1 the pulses of reduced rate are then applied to the correct one of lines el-eS as determined by the control circuit 3. V
The control circuit 3 is not discussed in detail here since it is an extremely complicated network. However, it should be clear that this circuit controls the timing of all the components of the taximeter and serves to carry out all the logical decisions generated in the computer 10. Thus the control circuit 3 carries out a number of synchronizing steps which together constitute the overall cycle. Thus in each cycle, counter 25 counts 48 steps, thereby addressing storage spaces a00 to a47 of storage 9. Counter 12 of course is operated in synchronism with counter 25. However, buffer storage 11 has only 10 storage locations, so that counter 12 counts 4.8 times for each individual runthrough of counter 25. Counter 12 is synchronized to counter 25 at the beginning of each overall cycle,
The adder comprises not only the first and second portions 26 and 27, but also comprises a carry storage 29. The signal generated in the carry storage is also applied to the control circuit 3. It will be noted that adder portion 27 also has inputs connected to the outputs of constant furnishing means 5, namely lines i4-il. However, the operation of the adder and the comparator will become clearer with reference to the following example:
At the beginning of each fare activation of the taximeter by actuation of either the keys for fare rate 1, 2, 3, or 4 the base fare is caused to be entered into indicator 14. Since the fare is to be stored in storage locations a00 to (104 of storage 9, these storage locations must of course be zero at the beginning of each trip and then must be advanced to the base fare, namely $1.25. The first cycle thus starts with the transfer of the value stored in storage location a00 of storage 9 to the portion 26 of the serial adder.
Since the output of counter 25 which is furnished on lines a, to a also constitutes the input to the constant furnishing means, line e00 of the constant furnishing means is energized simultaneously with the first storage location in storage 9. The value 5 stored in this position of constant furnishing means is thus transferred to portion 27 of the serial adder. At this time flip-flop FF10 is in the condition 10. The control circuit 3 now furnishes a signal via line k3 which is applied to both portions of the adder. Specifically adder 26 is caused to count forward, while adder 27 is forced to count in the reverse direction. Thus for the first pulse applied on line k3 the portion 26 is'increased by 1, while portion 27 is set to 4. Pulses are now applied by line k3 until adder 27 is set to 0. At this point no additional pulses are furnished on line k3 and the contents of adder 26 are transferred into the storage location (100 of storage 9. Storagev location al are not interrogated. The contents of this storage location is transferred to adder 26. Simultaneously line e01 of the constant furnishing means is energized so that the value 2 is entered into portion 27 of the serial adder via lines i1 to i4. In this case two pulses on line k3 are required until adder 27 stands at 0 and the numeral 2 is present in adder 26. Again, the contents of adder 26 are now transferred to third location a01. The process is now repeated with interrogation of the storage location a02 and a simultaneous transfer of the numeral 1 from the constant furnishing means via lines i1 to i4 to adder 27. Again, after transfer to adder portion 26 by means of the pulses applied on line k3, the numeral 1 is entered into storage location a02 in storage 9. The fourth and fifth place of the base fare each of which is zero in the above example, is then processed in the same fashion. At the end of this part of the cycle the value of $1.25 is thus stored in storage locations (100 to a04 of storage 9. It should also be noted that the same values were simultaneously entered into storage 11. Thus this value is now stored in storage 11 and is then transferred to the indicator means 14 during the remainder of this cycle.
Of course immediately upon the beginning of the trip, that is with activation of any of the keys indicating fare rate 1, etc., the measuring elements have begun to operate. Thus distance pulses are received at input 25 and timing pulses at input e3. Each distance pulse sets flip-flop FFS, each timing pulse flip-flop FF7. Further, flip-flop FFS is set as soon as any of the keys for fare rates 1 to 4 have been activated. It should be noted here that flip-flops FFl to FF8 are always interrogated in synchronism with the corresponding storage locations in storage 9. For example flip-flop FF2 is always interrogated simultaneously with storage location a09, since, under fare 11, the time and distance pulses together form the pulses for determining the fare increment after the base fare has been exhausted and, while the base fare is still in effect, these pulses together constitute the initial distance and must be stored here. Similarly, flip-flop FF3 is interrogated both when storage location a26 is interrogated and when storage location a30 is interrogated while the taximeter is operative. When the taximeter is not operative, flip-flop FF3 is only interrogated simultaneously with storage location a26. Storage locations a30 and a33 change its contents only when the taxi is operating with a fare, while storage positions a26 to a29 are advanced whenever the vehicle is in motion.
Following the above-described storing of values in storage locations a00 to a04, storage location a is addressed, simultaneously with flip-flop FF8. Flip-flop FF8 is set as soon as the vehicle has started and the first distance pulse has been received on line e5. If flip-flop FF8 is set, a pulse is applied to adder portion 27. Simultaneously the contents of storage location a05 are transferred into portion 26 and, as previously described, the contents of adder portion 27 are added to the contents of adder portion 26 and the resulting sum transferred back into the storage 9. If a carry-over signal is generated, this signal is stored in store 29 and is added when storing a value in the next subsequent storage location, that is in storage location a06. After the processing of storage locations a07 and n08, the contents of storage locations a05 to a08 is compared to the constant furnished at lines il-i4 of the constant furnishing means 5. If these are unequal, no output is furnished by comparator 28. However, when equality exists (2O distance pulses reached), a signal is furnished on line kl at the output of comparator 28 which is applied on line e4 as well as line e1, thereby setting flipflop FF2 and flip-flop FF9.
Next, storage location a09 is interrogated. At the very beginning of the trip, of course flip-flop FF2 is not set and storage locations a09 to al2 are set to Thus no change occurs in storage locations a09 to al2 at the beginning of the trip.
However, if flip-flop F1 2 has been previously set, a 1 is added to the contents of storage location a09 and, simultaneously, a comparison is carried out by comparator 28 between the new contents of storage location a09 and the constant value furnished at the output e09 of constant furnishing means 5. As previously mentioned, outputs e09 to e12, when flip-flop FFlO is in its first state, furnish a number corresponding to the initial distance, that is the number 250" Thus, if after a plurality of cycles the value stored in storage locations a09 to 012 corresponds to 250, flip-flop FFlO is switched from its first to its second state. However, a pulse for advancing the indicator is applied to flipflop FFl only after the contents of storage location a09 to al2 have increased to after the abovementioned change in flip-flop FF10. Only then can flipflop FF2 be set. Thus after the value 250" has been stored in storage locations a09 to al2 following the start of the trip and flip-flop FFIO has changed state, and the storage locations (109 to al2 have again reached the value 100 then a pulse is entered into flip-flop FF]. During the next cycle the fare increment is then added to the base fare previously stored in storage locations a00 to a04. That is, the constant furnished at outputs e00 and e01 of the constant furnishing means 5, that is the value of $0.25 is added in storage locations a00 and a01. This addition is also carried out in storage 11 and transferred to the indicator.
During the interrogation of storage locations a13 to a16, it is determined whether flip-flop FF4 is set, that is whether the additional charge key has been activated. If this is the case, a 1 is added in storage locations a13 to 016. The same is true for storage locations al7 to a20, when an additional charge has been entered. A 1 is also added in storage locations a21 to a25 when flip-flop FFI was set in the same cycle, that is when the fare increment of $0.25 is to be added. A 1 is added in storage locations a26 to a29 if flip-flop FF3 is previously set. The same is true for storage locations a30 to a33. A l is also added in storage locations a34 to a37 since the keys for fare rate 1, 2, or 3 were activated at the beginning of the trip. Storage locations a43 to a45 receive an additional l if flip-flop FF7 is set, that is if a timing pulse was received at input e3. At this point, as explained above, the pulse rate reduction in the ratio of 10:1 takes place before these pulses are applied to input e7 of stage 7.
It should be noted at this point that the time for one total cycle must be such that even for the fastest input rate at input e5 flip-flop FF8 can receive a pulse only once per cycle. Since a taxi is allowed to operate at a maximum velocity of kilometers per hour, approximately 400 pulses per second may arrive at input e5. The time for the total cycle of the storage must thus be less than 1/400 of a second.
To summarize the functioning of the arrangement of the present invention: At first the base fare is stored in storage locations 100 to a04. The distance pulses are stored in storage locations a05 to a08, while the time pulses are stored in storage locations a43 to a45. Thus, at fare rate 1, that is 2,000 pulses for each advance of the indicator, an output pulse is generated after pulses are stored in storage locations a05 to a08. This pulse is applied to input e4 of the mixing stage 7. Ten pulses are stored in storage locations 1143 to a45 until a single pulse is transferred to the input 27 of the mixing stage 7. The pulses at the output of the mixing stage 7, which selects the pulses having the highest pulse rate, are first stored in storage locations a09 to al2. While flip-flop FF10 is in its first state, these pulses are stored until the initial distance as furnished by constant furnishing means 5 has been passed. Thereafter flip-flop FF10 is switched to its second state. As soon as 100 pulses are stored in storage locations a09 to a12, a fare increment of $0.25 is added to the base fare of $1.25. In this way a current indication of the total fare is formed which is continuously transferred to storage 1 l and thence to the indicator 14. The same is true for additional charges which are entered manually and are continuously transferred from storage locations a1- 3-a16 into storage 11 and indicator 15. When the taxi is stopped at the completion of the ride, and the corresponding input key is depressed, no further time pulses are processed. The final fare is indicated on indicator l4 and indicator 15, being the sum of the so-indicated fares. The taximeter is reset to 0 by the activation of the unoccupied key which resets storage locations a00 to al6, a38 to a42 and a43 to a47. The values stored in the remaining storage locations are not extinguished, since they are required for effecting the final accounting between the driver and the fleet owner and thus must be maintained passed the individual rides.
If the taximeter is to be equipped for automatic rate changes, then corresponding constant values as applied at the output of constant furnishing means 5 by corresponding activation of lines e38-e42 at the output of decoder 21. These constants may correspond to a particular total fare, a particular distance travelled or a particular waiting time. In this case a taximeter has only one key for unoccupied and a second key for occupied." However, two fare rates are available on printed circuit board 23, that is two different pulse reduction rates are available. If the fare rate is to change after a predetermined total fare has been accumulated during one ride, then the fare as it accumulates is stored not only in storage spaces a00 to a04 but also in storage locations a38 to a42. As the storage 9 is interrogated during each cycle, a comparison is made between the value stored in locations a38 to a42 with the value stored in the constantfurnishing means 5, which signifies the fare at which the fare rate is to change. If this value has been reached then the constant furnishing means 5 are switched to the fare rate for fare rate 2, that is instead of lines v1 to v4, lines wl to w4 are energized so that the indicated fare is advanced not after 2,000 pulses, but already after 1,500 pulses.
The above-described operation is essentially the same as when the key for fare rate 2 is manually activated. This, too, causes lines W] to w4 rather than lines vi to v4 to be energized. Storage locations a05 to a08 then contain the reduction rate for fare rate 2 and a pulse is furnished to the input of stage 7 after 15 pulses have been received.
Transfer of the contents of storage locations al7 to a37 into buffer storage 11 and thence into the indicator 15 takes place in response to activation of one of keys 18. This, however, can only take place if the taximeter is otherwise not activated. When one of the keys 18 is activated, the corresponding command in coded form is entered into input storage 20 and is further transmitted to the control circuit 3. During the next cycle, the contents of the selected storage locations is transferred to buffer storage 11 and thus to the indicator 15.
The functioning of the computer means was described above as using a serial adder 26/27. This type of adder operates on one place at a time, that is it is not capable of operating on all place values in any number simultaneously. Thus the addition of two numbers, for example as described the addition of the number in part 27 to the number stored in part 26 can take considerable time, especially if a high number of places is to be processed. Since the incoming pulse rate can, however, be very large especially at high taxi velocities, it may be preferable to substitute a full adder for the serial adder 26/27. Such an adder could process two binary numerals in one operating cycle. Building blocks for such adders are commonly available and can be readily substituted for the serial adder described above.
It has been previously mentioned that it is particularly desirable to construct the taximeter in a highly integrated circuit technique, particularly in an MOS technique. In this type of circuitry as generally commercially available, only a given number of terminals can be furnished for any one building block. The taximeter must thus be so constructed that this available number of terminals is sufficient. FIG. 6 shows how the individual building blocks in integrated circuits can be arranged on a circuit board 30 and which terminals are required. Terminals e5, e3, e10 are required for the measuring elements, that is for furnishing the distance pulses, the time pulses and the synchronization pulses. Terminals al to a6 are required for addressing the decoder 21 in the constant furnishing means 5. Terminals i1 to [4 are required for the output lines of constant furnishing means 5. Terminals bl to b7 as well as cl to cl0 on decoders l3 and 13" respectively for connection to indicator 14/15. Indicator 14/15 is of course externally connected. The number of terminals enumerated above comes to 30, so that 10 more terminals remain for assorted purposes such as connecting the power supply. Thus it is possible that the control circuit 3, the pulse rate selector circuit 7, the storage and computer means 1 as well as buffer storage 11, address counter 12, decoding arrangement 13 and storage 20 may all be on one circuit plate which is executed in a highly integrated circuit technique. The externally available constant furnishing means 5, the indicator 14/15, the input and output operation keyboard 4 and the measuring elements are of course externally connectable.
It should further be stated that the constant furnishing means, rather than being constructed in the manner described above can also be executed in a highly integrated circuit technique. Such constant furnishing means are available commercially from a number of firms under the name of PROM (programmable-readonly memory).
While the invention has been illustrated and described as embodied in a taximeter using specific types of storage means, computing means and external constant furnishing means, it is not to be limited to the de tails shown, since various modifications and circuit changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended 1. Electronic taximeter comprising, in combination, first and second measuring means for furnishing, respectively, a first and second pulse sequence signifying distance travelled and elapsed waiting time, respectively; computer and storage means for computing the fare in response to said first and second pulse sequence, said computer and storage means having a first storage means for storing variables required for computing said fare and additional variables for computing totals required for calculating the pay of the taxi driver; electronic indicator means having a plurality of indicator elements, each adapted to furnish a visual output only in the presence of a signal applied thereto; buffer storage means connected to said first storage means and said indicator means, said buffer storage means having a plurality of buffer storage locations corresponding in number to said plurality of indicator elements, each for storing data received from said first storage means and for applying corresponding signals to a corresponding one of said indicator elements when addressed; and control circuit means for cyclically addressing said buffer storage locations in a predetermined order and at a rate sufficient to effect a visually continuous output from each of said indicator elements.
2. An electronic taximeter as set forth in claim 1, wherein said first storage means has a plurality of first storage locations exceeding in number said number of buffer storage locations, said plurality of first storage locations including predetermined first storage locations for furnishing said data to said buffer storage locations when addressed; and wherein said control circuit means further comprise means for cyclically addressing said first storage locations in synchronism with said addressing of said buffer storage locations.
3. An electronic taximeter as set forth in claim 2, wherein said computer and storage means further have means for computing said totals from said variables and storing said totals in said first storage means; further comprising means for storing data corresponding to extra charges to be applied during a trip in corresponding predetermined ones of said first storage locations; wherein said plurality of buffer storage locations includes a first and second set of buffer storage locations, for, respectively, indicating the individual fare and said extra charges when said taximeter is carrying a passenger; wherein said indicator means comprises first and second indicator portions connected, respectively, to said first and second set of buffer storage locations; further comprising a plurality of externally activatable selector elements, each for transferring one of said totals to a buffer storage location in said second set of buffer storage locations when said taxicab is not carrying passengers, whereby said indicator portion further includes a selected one of said totals upon activation of the corresponding one of said selector elements when said taxicab is not carrying passengers.
4. Electronic taximeter as set forth in claim 1, wherein said totals comprise the total fare collected, the number of trips, the distance travelled by the taxi in an occupied state, the distance travelled in an unoccupied state, the total number of additional charges.
5. An electronic taximeter as set forth in claim 1, wherein said control circuit means comprise means for furnishing a sequence of control pulses, address counter means connected to said means for furnishing a sequence of control pulses and to said buffer storage means, for counting said control pulses and furnishing address signals addressing said buffer storage locations in response to the so-counted number of pulses, and connecting means for connecting said buffer storage means to said indicator means in such a manner that data in each so-addressed storage location is transferred to the corresponding one of said indicator elements.