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Title:
VOICE ENTRY SYSTEM
United States Patent 3641500
Abstract:
An arrangement is disclosed for making entries into an information system from a plurality of remote locations by voice communications. The arrangement comprises a speech compression means and an audio buffer means associated with each location, the speech compression means functioning to compress the duration of a message whereby a keyboard operator receiving the voice communications can handle a plurality of locations, the audio buffer means being operative to store the compressed message. There is also associated with each location a word counter which contains a count of the words in a message, a count in a word counter signifying that a complete message is in the audio buffer enabling the locations where that message has been entered to have that message processed. The arrangement includes a sequencing unit which establishes which location can receive processing. The keyboard operator enters the messages into an information-processing system and the results of this processing are then transmitted back to the appropriate locations where they can be printed out or otherwise be availed of.


Inventors:
Greanias, Evon C. (Chappaqua, NY)
Levine, Wilbur J. (Poughkeepsie, NY)
Application Number:
05/051303
Publication Date:
02/08/1972
Filing Date:
06/30/1970
Assignee:
International Business Machines Corporation (Armonk, NY)
Primary Class:
Other Classes:
360/8
International Classes:
G06F3/16; G07G1/10; (IPC1-7): H04Q9/00
Field of Search:
340/152 235
View Patent Images:
Other References:

information Display, November/December, 1964, "Voice Response and Visual Display Techniques" Avakian et al., pp. 12-19..
Primary Examiner:
Yusko, Donald J.
Claims:
What is claimed is

1. An arrangement for making information entries into a processing system, processing said information entries, and providing the results of said processing, wherein said entries are made by voice from a plurality of remote stations and said results and/or suitable operational signals are provided to said stations, said arrangement comprising:

2. An arrangement for making information entries into a processing system, processing said information entries, and providing the results of said processing and/or suitable operational signals, wherein said entries are made by voice from a plurality of remote stations, each entry comprising a chosen number of words, and said results and said signals are provided to said stations, said arrangement comprising:

3. An arrangement for making information entries into a processing system, processing said information entries, and providing the results of said processing, wherein said entries are made by voice from a plurality of remote stations, each entry comprising a chosen number of words, and said results and/or suitable operational signals are provided to said stations, said arrangement comprising:

4. An arrangement for making information entries into a processing system, processing said information entries, and providing the results of said processing, said entries being made by voice from a plurality of remote stations, each entry comprising a chosen number of words, said respective results and/or suitable operational signals being provided to said stations, said arrangement comprising:

5. An arrangement as defined in claim 4 wherein processing results output means is provided respectively associated with each station.

6. An arrangement as defined in claim 4 and further including means for providing an audio signal to said locations to indicate that an entry therefrom can be received by the arrangement.

7. An arrangement as defined in claim 4 and further including means for decrementing the count of words in a word counter as said words are entered into said information system by said keyboard.

8. An arrangement as defined in claim 4 wherein each of said speech compression means include a voice detect component which provides an output in response to an average audio level which exceeds a chosen threshold and a delay component for providing a delay interval for a voice input signal which corresponds to the averaging period of said voice detect device, a word counter being incremented in response to the actuating of said voice detect component.

9. An arrangement as defined in claim 8 wherein an audio buffer means includes a tape loop, a drive for said loop, and write and read heads for said loop, the actuation of said voice detect component causing the gating of said voice signal to turn on said write head and the actuation of said drive, the termination of the actuation of said voice detect component causing the turning off of said write head and the halting of said drive.

10. An arrangement as defined in claim 9 wherein the attaining of said chosen number in a word counter at a particular station and the establishing of said station for processing by said sequencing means causes the actuation of the tape drive and the read head of said station to play back the information on said loop for entry into said system by means of said keyboard.

Description:
This invention relates to voice entry systems. More particularly, it relates to an arrangement for making entry into an information-processing system from remote locations by means of voice communications.

There are many job situations wherein an employee generates or collects information as a byproduct of his principal task and is so occupied by his primary duty that he cannot operate or, perhaps, even learn to operate a conventional keyboard efficiently.

For example, at a supermarket checkout point, the cash register ring up and the bagging of merchandise involves a fundamental inefficiency because each item of merchandise must be handled twice by checkout personnel, viz; a first time to be rung up and a second time to be bagged. The period for bagging a single item is approximately 3 seconds, and the period for ringing up an item is about 2 seconds.

It has been ascertained that digits can be spoken at a rate of two or three digits per second but that a reasonably good keyboard operator can enter at least six digits per second with a ten-key keyboard.

It is thus quite evident that in a situation such as the above-described supermarket checkout example, vastly improved efficiency could be attained if the time consumption were to be essentially reduced to bagging only.

Similar time consumption problems and inefficiencies flowing therefrom obtain in a hospital, for example, at the point of information system data entry.

Accordingly, it is an important object of this invention to provide an arrangement for making entries into an information-processing system from remote locations.

It is another object to provide an arrangement in accordance with the preceding object wherein the users of the information-processing system may work at many different locations which have conventional telephone service, and wherein it would be uneconomical to provide effective key entry devices at each station.

It is a further object to provide an arrangement in accordance with the preceding objects which can be utilized with keyboards or with voice recognition devices.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided an arrangement for making entries into a processing system, processing the information entries, and providing the results of the processing, the entries being made by voice from a plurality of remote stations, each entry comprising a chosen number of words, and the processing results are provided back to the stations. Included in the arrangement are speech compression means, audio buffer means, a word counter and read control means respectively associated with each of the stations. The speech compression means is operative to compress the duration of the number of words in an information entry. The audio buffer means stores the compressed information entry. The word counter means functions to contain a count of the words of an information entry and the read control means operates to present the stored entry in the audio buffer to the operator of a keyboard which is employed to enter the information entries into an information-processing system where the entries are processed. Provided in the arrangement is a sequencing means, which, in response to states of the word counters, establishes the station whose information entry is to be processed. The information-processing means provides the results of the processing of the information entries to output means such as printers respectively located at each station.

The foregoing and other objects features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing, FIG. 1 is a block diagram which depicts the general organization of the arrangement constituting the invention;

FIG. 2 is a diagram which details certain features of the arrangement of FIG. 1 for a particular application of the invention;

FIG. 3 is a diagram of an illustrative structural embodiment of the invention;

FIG. 4 is a flow diagram of the microprogram effected by the sequence pulse generator of FIG. 3;

FIG. 5 is a flow diagram of the microprogram effected by the process pulse generator of FIG. 3;

FIG. 6 is a diagram of the arrangement at station A;

FIG. 7 is a diagram of the arrangement at station B;

FIG. 8 is a diagram of the arrangement at station C;

FIGS. 9A and 9B taken together as in FIG. 9 depict an illustrative embodiment suitable for use as the audio buffer A in the embodiment shown in FIG. 3;

FIGS. 10A and 10B taken together as in FIG. 10 show an example of an embodiment suitable for use as the audio buffer B of FIG. 3;

FIGS. 11A and 11B taken together as in FIG. 11 show an example of an embodiment suitable for use as the audio buffer C of FIG. 3;

FIG. 12 is a diagram of an illustrative embodiment of a keyboard suitable for use in the system shown in FIG. 3;

FIG. 13 is a diagram of an illustrative embodiment of an arrangement suitable for use as the error detect stage in the system of FIG. 3;

FIG. 14 is a diagram of an arrangement suitable for use as the audio response unit of the system of FIG. 3;

FIG. 15 is a depiction of an arrangement suitable for use as the random access memory stage of the system of FIG. 3;

FIG. 16 is a diagram of an arrangement suitable for use as the total accumulators stage of the system of FIG. 3;

FIGS. 17A to 17E taken together as in FIG. 17 depict an embodiment of the central controls stage of the system of FIG. 3;

FIG. 18 is a diagram of an embodiment of the process pulse generator of the system of FIG. 3; and

FIG. 19 is a diagram of an embodiment of the sequence pulse generator of the system of FIG. 3.

DESCRIPTION OF A PREFERRED EMBODIMENT

The conceptual embodiment which is first described hereinbelow is an application to the supermarket checkout situation. According to the invention, and as shown in this embodiment, the checkout operation is reduced to bagging only of an item with voice communication to a central keyboard operator as the item is bagged, to record the item sold, obtain its current price, and update the inventory records.

It has been mentioned hereinabove that digits can be spoken at a rate of two or three digits per second but that a reasonably proficient keyboard operator can enter more than six digits per second on a ten-key keyboard. It is readily apparent, therefore, that to achieve optimal efficiency, the rate at which digits are presented to the keyboard operator has to be increased. Thus, a feature of the invention resides in the fact that the checkout employee is given a relatively short interval such as approximately 2 seconds to read a four to six digit code number, for example, from an item of merchandise into a headset microphone. The beginning of the interval may be indicated by an audio signal in the headset earphones, and the spoken digits are recorded on audio tape as they are uttered. At the end of this interval, the tape is accelerated and played back to the keyboard operator in a shorter interval such as about 1 second. With this arrangement, the rate of presentation to the keyboard operator is virtually doubled, i.e., about one message or four to six characters per second, and causes the sounds on the tape to rise in pitch.

In connection with the foregoing, it has been found that spoken digits are readily understood when the playback time is six-tenths as long as the recording time. Additional reduction of playback time can be achieved by reducing the periods of silence between words. For conversational speech, these have been estimated to be 10 percent of the speaking time. For spoken digits, the silence periods are greater, i.e., about 25 percent of the time. Thus, if the 2 second speech interval is reduced 20 percent (from 2.0 to 1.6 seconds) and the playback interval is reduced to 60 percent, a one message per second presentation rate can be achieved without excessive pitch elevation.

If the bagging is effected at a rate of 3 seconds per item, and the keyboard operator's equipment is switched automatically to provide properly phased signal tones and to accept output from successively arranged checkout stations at 1 second intervals, then one keyboard operator can readily handle three checkout stations and the total time required to handle each customer at the checkout station is reduced to the bagging time plus the time required to make change.

Reference is now made to FIG. 1 wherein there is illustrated the inventive concept as applied to the supermarket checkout situation. In the arrangement shown in this FIG., there are shown three checkout stations wherein checkout personnel speak to their respective microphones 11, 12, and 13 after they have received an audio signal from an audio response unit 10. The latter signal could be, for example, the term "ready" for the first item of an order and one or two characters related to the previous item such as the check digit and quantity for subsequent items. Each of microphones 11, 12, and 13 are, of course, suitably gated to block out speech during a voice answer back period.

The speech input at each station is applied to a speech compression unit respectively associated with the station. In FIG. 1, for convenience, there is shown only speech compression unit 15, which is associated with station 11, i.e., with microphone 11. The speech compression units are operative to reduce speech duration. As has been mentioned above, in addition to the elimination of interword silences, such speech compression can be achieved, for example, by braking speech up into successive time slots and then reassembling it, omitting every nth time slot sample to achieve a shorter duration without elevating pitch.

A speech compression unit 15 provides inputs for an audio buffer stage 14 and a word counter 16 there being an audio buffer and a word counter associated with each speech compression unit. The function of an audio buffer is to receive the intervals of audio signals that have been retained by a speech compression unit 15 and to assemble these intervals into shorter durations but still intelligible speech. A word counter 16 receives inputs that correspond to interword silence periods detected in the speech compression unit. A word counter 16 is decremented by one by a pulse produced from a keyboard 18 whenever an entry is made by the keyboard operator.

The state of a word counter 16 is employed to control a service sequencer stage 20, the function of service sequencer stage 20 being to establish the checkout station which is to be operated. The state of a word counter 16 also controls the rate of compressed speech playback from an audio buffer 14 to the headset of the operator of keyboard 18 by controlling a read control stage 22, a read control state 22 being also provided for each checkout station. With appropriate logic as contained in a control logic stage 24, the playback rate is increased when a larger number of words is stored in word counter 16 and is reduced when the words stored in word counter 16 are fewer in number. A read control stage 22 is constructed whereby it presents messages to keyboard 18 word by word.

The entries of the keyboard operator made into keyboard 18 go to a unit 26, legended file and processor. Processor unit 26 suitably contains the description, price and inventory status of the many thousands of items stocked by the supermarket. When an item number designation is entered into file and processor unit 26 and verified therein against its check digit, the price of such item and one or two identifying digits, such as its check digit and quantity, are transmitted to audio response unit 10 and to a printout control unit 28, which controls respective printers located at each checkout station, there being shown in FIG. 1 respective printers for stations 11, 12, and 13. Printout control unit 28 transmits the descriptive information and price to the appropriate printer, and audio response unit 10 transmits the recorded sound of the selected digits to a voice answer back control stage which in turn transmits these sounds to the appropriate checkout station headset. A signal from voice answer back control stage 30 is also operative to gate out speech from the microphone at the particular checkout station during the voice answer back period.

There is also shown in the arrangement in FIG. 1, an input/output stage 32, which can receive an input from file and processor unit 26. Stage 32 may be, for example, a card or tape reader for entering new items, changing prices, etc., or may be a visual display unit for the keyboard operator's use in certain situations.

Reference is now made to FIG. 2 wherein there is shown in greater detail, particular features of the inventive concept, i.e., more detailed implementations for the speech compression and audio buffer units.

As has been mentioned hereinabove, a speech compression unit is operative to remove interword silences to thereby reduce speech duration. Accordingly, it includes a voice detect device 34 which provides an output gate as long as the average audio level exceeds a fixed threshold. A delay stage 36 is provided to delay the voice input signal for an interval corresponding to the averaging period of voice detect device 34. When voice detect device 34 is actuated, it advances word counter 16 (FIG. 1) and gates the audio signal to audio buffer 14. If audio buffer 14 is chosen to be a tape loop 39, the audio signal is gated to the write head associated with loop 39 and starts the tape drive for the audio buffer record 38. In this connection, it may be arranged such that only the tape drive for audio record 38 is operated during record intervals and the length of tape loop 39 is increased as each word is recorded. The size of tape loop 39 corresponds to the state of word counter 16. When voice detect stage 34 is deactuated, the write head for loop 39 is turned off and the tape drive is halted. The actions of delay stage 36 and detect stage 34 are intended to provide relatively small fixed periods such as about 10 milliseconds of silence on tape loop 39 during the periods of tape start and stop.

Playback begins when service status is imparted to a particular station, suitably by means of a gating or other arrangement. Such imparting of service status occurs when the word counter for that station contains a count, for example, of a chosen number of words and other service requests are not present. With this chosen number count status, in the particular word counter, playback by a read stage 42 is initiated when the enabling of the service status gate actuates a start read stage 40, which may suitably be a trigger circuit. Playback continues until start read stage 40 turns off in response to a small fixed period of silence that was recorded on tape loop 39 and is detected by a word end detect unit 44. Reading of the next word begins when start read trigger 40 is actuated by a signal from keyboard 18. The output of keyboard 18 also decrements word counter 16 and, as long as the keyboard is operated in conjunction with the rate of recording on tape loop 39, word counter 16 does not attain a count of the chosen number. Such "on-off" playback mode continues until word counter 16 and tape loop 39 returns to their zero states and the service status gate is deactivated.

If the rate of recording on tape loop 39 should exceed the rate of operation of keyboard 18, the contents of word counter 16 will advance to a count exceeding a given number and, by the action of a high-speed control stage 46, high-speed reading may be initiated, i.e., the rate of presentation of information to the operator, and continue until word counter 16 is again decremented to a state not exceeding the given number.

It can be appreciated that the playback control arrangement, according to the invention, permits the operator of keyboard 18 to match the audio recording rate on loop 39. Should the operator fall behind, the system takes control and presents the playback at a faster rate to cause the keyboard operator to increase his rate of keying.

In considering the inventive concept as thus far, it is seen that the invention is characterized by two important capabilities for efficient data entry, viz:

1. Data entry is enabled to be effected in real time by employees that are primarily engaged in another task (bagging in the supermarket example) without the need for any major changes in their primary tasks or for acquiring significant new skills. 2. A natural and convenient mode of communication, i.e., voice, is used for data entry by employing a keyboard operator to translate voiced information into machine code and for enabling the matching of throughput rate of the keyboard operations.

Reference is now made to FIG. 3 wherein there is shown a preferred embodiment constructed in accordance with the principles of the inventive concept and FIGS. 4-19, which illustrate in more detailed form the components and the operation of the system shown in FIG. 3.

In FIG. 3, it is seen that three stations A, B and C, designated 101, 103 and 105 respectively, are shown by way of example. Since the structures at these stations are the same, reference need only be made to FIG. 6 wherein there is shown the structure of station A to understand the structures at all of these stations.

In FIG. 6, it is seen that the structure at a station includes a microphone 115, a telephone headset 113 and a printer 117. In the supermarket application, wherein a station is a checkout counter, it is assumed, in accordance with this embodiment, that each item is identified by a six digit decimal number. These six digits are spoken into microphone 115 by the employee at the station. The least significant digit is a check digit and suitably chosen to be the modulo nine sum of the other five digits. These six digits, i.e., six audio words, are transmitted through microphone 115 on a line 100 to the audio buffer 107 for station A. Line 100 is arranged to carry an audio tone signal such as "beep," the tone indicating to the operator at the station that he can speak the next six words into his microphone. A line 106 to headset 113 carries an audio response message such as "repeat." This occurs where an error is transmitted, and the worker of the station A is asked to repeat the six words. Printer 117 is arranged in the supermarket application, for example, such that it is caused to print each sales item on a line together with its price and the total amount when all of the items and their prices have been printed. The item data is presented to printer 117 on a cable 112, and the total data is presented to printer 117 on a cable 114. When it is desired to print an item, a signal is applied to a line 108, and the data present on cable 112 is printed as the item and price. When the total tabulation of items is complete, a signal appears on a line 116. When a signal is applied to line 110, the total is printed at its proper place, and when the latter printing is completed, a signal again appears on line 116 to indicate that the printing is completed. A chosen six digit number may be utilized by the employee at the station to indicate that a total is requested. Such number, for example, could be 999990. When the latter number is detected, the total is caused to be printed. It is noted that lines 104, 106, 118, 110 and 116 and cable 112 extend from a central control stage 251, (FIG. 3), the operation of stage 251 being explained in greater detail hereinbelow.

AUDIO BUFFER

Reference is now made to FIG. 9, wherein there is shown an audio buffer such as audio buffer 107, (FIG. 3), for station A. Here again, each of the respective station audio buffers are the same so that only one is described.

Each audio buffer contains a word counter, such as word counter 119 for audio buffer 107. Word counter 119 has six output lines respectively designated by the numerals 164, 166, 168, 170, 172 and 174, all of these lines terminating in a cable 160, which goes to central control stage 251 (FIG. 3). Line 164 is active if the number in counter 119 is zero and line 166 is active if the number in word counter 119 is not zero; line 168 is active if the number in word counter 119 is 3 and line 170 is active if the number in word counter 119 is not 3; line 172 is active if the number in word counter 119 is 6 and line 174 is active if the number in word counter 119 is not 6.

Line 174 is also employed, when it is active, to gate the information on line 100 to a speech compressor 123 by activating a gate 121. With this arrangement, the microphone at a station is effective as long as there is less than a count of six words in word counter 119. When the count in word counter reaches 6, line 174 becomes inactive, and further information on line 100 is prevented from entering into speech compressor 123.

An audio buffer can suitably be a tape unit having a major and a minor tape loop and wherein suitable feed rolls move the tape past a write head 125 and into the minor loop, which provides storage between write head 125 and the read head 127. Since such an arrangement is well known, no further description or depiction of its structure is deemed necessary. A delay stage 147 is provided to delay the application of the output of speech compressor 123 to write head 125.

With such tape unit, there is provided a write engage clutch magnet 129 to engage the feed rollers and to latch them closed to move the tape past write head 125. A write disengage clutch magnet 131 is employed to release the latch imposed by write engage clutch magnet 129 to thereby halt the movement of the tape past write head 125.

The output of speech compressor 123 is applied to a clipping amplifier 133, which is effectively operative to produce a positive square wave for each spoken word. The positive shift of the output square wave from clipping amplifier 133 is detected by stage 135, which is a circuit for detecting and amplifying the positive shift. The negative shift of the output square wave from clipping amplifier 133 is detected in a stage 137, which is a circuit for detecting and amplifying the negative shift. The output of circuit 135 is applied to write engage clutch magnet stage 129, and the input of circuit 137 is applied to write disengage clutch magnet stage 131 and to increment word counter 119.

The read station, i.e., read head 127, of the audio buffer is also provided with a read engage clutch magnet 139 and a read disengage clutch magnet 141. As shown in FIG. 9, the movement of the tape past read head 127 is caused by the activation of a line 156 from central controls 251 (FIG. 3) and the stopping of the tape is caused by the activation of a line 158 from central controls 251, lines 156 and 158 being included in a cable 154. The output of read head 127 is also amplified and square waved by a clipping amplifier 143 and a stage 145, which is a circuit for detecting and amplifying the negative shift of the output of clipping amplifier 143, is employed to decrement word counter 119.

KEYBOARD

An illustrative embodiment of the keyboard 235 (FIG. 3) is shown in FIG. 12. The keyboard 235 suitably comprises 10 key contact sets as shown for the digits 0-9 respectively, one contact of each contact set being connected to a voltage source. In addition, keyboard 235 is provided with an accept switch 239, which an operator can place in the "Off" position if he has to leave the keyboard. When switch 239 is placed in such "Off" position, the system stops after the last item has been processed. The depression of any of the keys 0-9 can increment a stroke counter 243 through an OR-circuit 241, stroke counter 243, in accordance with this embodiment, being arranged to count three strokes. The three stroke amount has been chosen as an illustration because it is believed that using a six digit number to identify a sales item is more readily intelligible to a keyboard operator if it is divided into two bursts of three digits. When the keyboard is connected to an audio buffer, as is further explained hereinbelow, the keyboard operator receives a burst of three digits from the buffer. The operator then first keys these three digits into the keyboard, and, after a short interval of time, the operator receives the next three digits. The manner in which this is accomplished is as follows:

When an audio buffer is first connected to the keyboard, the read engage clutch magnet (FIG. 9, for example) is engaged. When the first three words of the six digit number are counted in word counter 119, the read disengage clutch magnet is operated which halts movement of the tape and the operation of the audio buffer. When the keyboard operator keys in these first three digits, the read engage clutch magnet is again energized, and the last three digits are read from the buffer to the keyboard operator. The key contacts 1-8 (FIG. 12) go via a cable 236 to the error detect mechanism 345 (FIG. 3). All of contacts 0-9 of keyboard 235 go via a cable 238 to a random access memory 245 (FIG. 3).

In the keyboard shown in FIG. 12, it is noted that "ON" line 234 and "OFF" line 232 are part of a cable 226 which extends to central controls stage 251 (FIG. 3). Stroke counter 243 has two output lines, a line 230, which is active when the setting in stroke counter 243 is "3" and a line 225, which is active when the setting in stroke counter 243 is other than "3," lines 228 and 230 also going to central controls 251 as part of cable 226. Stroke counter 243 is reset when a line 224 from central controls 251 and in cable 220 is active. The line 222 is to the keyboard operator's headset and is also in cable 220 from central controls 251.

ERROR DETECT UNIT

Reference is made to FIG. 13 wherein an illustrative embodiment of error detect stage 237 is shown in greater detail. In the operation of this embodiment, the first five digits from the keyboard are transmitted to a mod 9 accumulator 149 through a gate 247 to produce the modulo 9 sum of the first five digits. The latter sum is then compared in a compare unit 151 with the sixth digit, which is provided from random access memory 245 (FIG. 3). If the comparison shows equality, the output line 244 from compare unit 151 to central control 251 is active. If the comparison shows inequality, then the output line 246 of compare unit 151 to central controls 251 is active.

AUDIO RESPONSE UNIT

An illustrative embodiment of this unit is shown in FIG. 14. In this unit, a request for the audio response is made by applying a P-14 pulse (as is further explained in the description of the P-clock (FIG. 18) to the audio response unit. The actual audio response, which may be the word "repeat," for example, appears on a line 256, which is routed back to the associated station operator's headset. A signal appears on a line 254 when the audio response is completed. It is seen in FIG. 14 that lines 254 and 256 are in cable 252, which goes to central controls 251.

The audio response unit suitably contains a tape loop, drum or disk, on which there is present the magnetic sound track of the response word or message, in this case the word "repeat." The latter word or message is delivered over to the output line upon request.

RANDOM ACCESS MEMORY

An illustrative embodiment of the random access memory 245 (FIG. 3) is shown in FIG. 15. In this component, there is provided an address assembly register 249, which receives its input via a cable 238 from keyboard 235 (FIG. 12) and which contains up to six decimals. These digits are entered into register 249, one by one, via cable 238. Thus, it is understood that six consecutive depressions of keys on keyboard 235 will fill register 249, the lowest order digit being the check digit. This check digit is transmitted via cable 248 to error detect unit 245 (FIG. 3).

As has been mentioned above, a special digit configuration, such as 999990, can be employed to indicate a request for a total. These digits can be provided to a decoder 253 by a cable 255, and if a total is requested, i.e., the presentation of the combination 999990 to decoder 253, an output line 266 of decoder 253 is active. If a total is not requested, then, of course, an item is to be printed, and a line 264 is consequently active.

A read access of the memory is initiated by the P22 pulse of the P-clock (FIG. 18), which is applied to the line legended "request read access." When the read access is complete, a pulse appears on an output line 268 from the memory. The operation of the read access is to load a data register 257 with the particular item description and its price. The contents of data register 257 are transmitted to central controls 251 through a cable 270 and cable 262, from which they are routed back to a printer at the appropriate checkout station. The contents of the price field in data register 257 are transmitted to an appropriate total accumulator 259 (FIG. 3). In this connection, it is realized that a total accumulator is provided for each station.

TOTAL ACCUMULATOR

An illustrative embodiment of a total accumulator 259 (FIG. 3) is shown in FIG. 16. In this FIG., it is seen that the contents of the price field of data register 257 (FIG. 15) are transmitted via cable 258 to the appropriate station accumulator through an associated gate. The gate is actuated upon the enabling of an AND-circuit by the coincidence of the P25 pulse (P-clock, FIG. 18) and a signal indicating the particular station, viz A, B or C. The outputs of accumulators A, B and C, are transmitted to stations A, B and C through cables 114, 132 and 150.

PROCESS PULSE GENERATOR (P-CLOCK)

The process pulse generator 261 (FIG. 3) is shown in detailed form in FIG. 19. It comprises 27 monostable multivibrators P1-P27. The latter are arranged whereby they are actuated by the respective inputs thereinto. For convenience, the actuated, i.e., astable output of a monostable vibrator circuit is given the same designation as the circuit itself. Thus, for example, the output of monostable multivibrator P1 is pulse P1. The output line of a monostable multivibrator circuit produces a pulse when the circuit goes "OFF," and this pulse can be employed to activate, i.e., turn "On," another monostable multivibrator. The clock pulses P1-P27 are transmitted via a cable 312 to central controls 251 where these pulses are employed to interrogate gates and perform other functions. The lines in a cable 314 come from central controls 251 and are utilized to actuate, i.e., turn "On" certain monostable multivibrators when branching of the microprogram is required.

SEQUENCE PULSE GENERATOR (S-CLOCK)

The sequence pulse generator comprises monostable multivibrators as the timing pulse sources, and are constructed similar to those in the process pulse generator. As seen in FIG. 19, it comprises 21 monostable multivibrator circuits, the pulse output of a circuit having the same designation as the circuit itself. This pulse generator is employed to interrogate the stations (A, B and C in this embodiment) and to determine whether or not any of these stations require processing service. In this connection, when the contents of a word counter in an audio buffer are at 6, the signify that an item can be processed. By "processing," it is meant that the keyboard operator can be connected to the particular audio buffer and key in the six digits to the system. The system will then process the request, whether the latter is for an item or for a total.

CENTRAL CONTROLS 251

An illustrative embodiment of the central controls 251 is depicted in FIGS. 17A-17E, taken together as in FIG. 17. This structure contains most of the logic needed for the operation of the system, all of the units in the system interacting therewith.

In considering the operation of the inventive system, there is first explained the sequence microprogram. For this explanation, reference is made to FIG. 3, i.e., the overall diagram of the embodiment being described; FIG. 4, which is a flow chart of the sequence microprogram; FIG. 19, which shows the sequence pulse generator, i.e., the S-clock; and FIG. 17, which depicts the central controls.

As seen in FIG. 19, the S-clock is started by a start pulse applied to an OR-circuit 275, the output of OR-circuit 275 turning on monostable multivibrator S1 to produce pulse S1. The function of the S1 pulse is to test accept switch 239 (FIG. 12) to determine whether the switch is on or off, i.e., pulse S1 is applied to a gate 475, FIG. 17E. Also applied to gate 475 are lines 232 and 234 from the keyboard, the active state of line 232 signifying that switch 239 is "OFF," the active state of line 234 indicating that switch 239 is "ON." The active state of output line 278 of gate 475 indicates that the switch 239 is "ON," and the active state of output line 276 of gate 275 indicates that switch 239 is "OFF." If switch 239 is "OFF," then the microprogram branches to monostable multivibrator S2. The pulse S2 output is used for delay only, and at its termination, reactuates monostable multivibrator S1 through OR-circuit 477. However, if switch 239 is "ON," then monostable multivibrator S3 is actuated by active line 278 to produce pulse S3.

The function of pulse S3 is to test the contents of the word counter in an audio buffer to ascertain whether or not it is in the "6" state. This is accomplished by applying pulse S3 to gate 285 (FIG. 17E), the input lines to gate 285 being output line 172 of word counter 119 in audio buffer A, the active state of line 172 indicating that the contents of word counter 119 are at "6," and the active state of line 174 indicating that the contents of word counter 119 are not at "6." If the contents of word counter 119 are at "6," then an output line 280 of gate 285 is active, the active state of line 280 being employed to actuate monostable multivibrator S4. The actuating of monostable multivibrator S4 initiates processing from audio buffer A. To effect this initiation, pulse S4 is applied to OR-circuit 361 (FIG. 17), the output of OR-CIRCUIT being applied to a line 316, the active state of which is utilized to actuate monostable multivibrator P1 in the process pulse generator, i.e., the P-clock (FIG. 18). However, if the contents of word counter 119 are not at "6" whereby output line 174 thereof is active, then monostable multivibrator S5 is actuated by the active state of output line 282 of gate 285 (FIG. 17E). Pulse S5 is applied to a gate 287, the input lines to gate 287 being A and A respectively, the active states line A and line A indicating whether or not the processing from audio buffer A is completed. In this connection, A flip-flop 153 had been set by pulse S4. If output line 284 of gate 287 is active, indicating that processing of audio buffer A is not completed, flip-flop 153 is still in its "1" state. Line 284 actuates monostable multivibrator S6 to produce pulse S6 therefrom, the latter pulse again turning on monostable multivibrator S5 through an OR-circuit 281, pulse S6 being used for delay only. However, if processing from buffer A is complete, i.e., flip-flop 153 is in its "0" state; then output line 286 from gate 287 is active; and the microprogram advances to monostable multivibrator S7. The function of pulse S7 is to connect the tone generator 303 through OR circuit to the headset at station A and to deliver a short beep to inform the operator at station A that he can speak the next six words. In this connection, pulse S7 is applied to gate 155 (FIG. 17F), the output of gate 155 being applied to line 106, which via cable 102 goes to station A.

When pulse S7 terminates, it is applied through an OR-circuit 287 to turn on monostable multivibrator S8. Pulse S8 is again utilized to test the state of switch 239 (FIG. 12).

This is accomplished by applying pulse S8 to a gate 277, the input lines to gate 275 being line 232, which, when active, indicate that switch 239 is "OFF" and line 234, the active state of which indicates that switch 239 in "ON." Output line 288 of gate 275, when active, signifies that switch 239 is "OFF" and the active state of output line 290 of gate 275 indicates that switch 239 is "ON." If switch 239 is "OFF," then active line 288 actuates monostable multivibrator S9, the output pulse S9 being applied through OR-circuit 287 to reactuate monostable multivibrator S8, pulse S9 being used for delay only. If switch 239 is "ON," then the active state of line 290 actuates monostable multivibrator S10 which is employed to test whether the contents of the word counter in audio buffer B are or are not at "6." To this end, pulse S10 is applied to a gate 293, the input lines to gate 293 being line 194, which is the output line from the word counter in audio buffer B which indicates that the contents of the word counter are at "6" and the output line 196 from the word counter in audio buffer B, the active state of line 196 signifying that the contents of this word counter are not at "6." Correspondingly, the output line 292 of gate 293, when active, signifies that the audio buffer B-word counter contents are at "6" and output line 294 of gate 293, when active, signifies that the audio buffer B word counter contents are not at "6."

If the contents in the word counter of audio buffer B are at "6," then the active state of line 292 actuates monostable multivibrator S11, which initiates processing from the audio buffer B by switching to its "1" state a flip-flop 295 to actuate the gate 297. However, if the contents of the word counter in audio buffer B are not at "6," then the active state of output line 294 of gate 293 is applied through an OR-circuit 299 to turn on monostable multivibrator S12, pulse S12 being applied to a gate 301. The input lines to gate 301 are then set output line B and the reset output line B of flip-flop 295, the active states of the latter lines respectively signifying that the processing in audio buffer B is not or is completed. If it is not completed, then output line 296 of gate 301 is active to actuate monostable multivibrator S13, pulse S13 being applied through OR-circuit 299 to again actuate monostable multivibrator S12, pulse S13 being used for delay only. However, if processing in audio buffer B is completed, then output line 298 of gate 301 is active to turn on monostable multivibrator S14. Pulse S14 is employed to deliver a beep signal to station B by being applied to tone generator 303 through OR-circuit 305.

When pulse S14 terminates, it is applied through an OR-circuit 307 to actuate monostable multivibrator S15. The pulse S15 is used to test for the state of the accept switch. Such testing results from the applying of pulse S15 to gate 309 (FIG. 17E). The input lines to gate 309 are lines 232 and 234, which respectively, when activated, indicate an "OFF" and an "ON" state of the switch. If the switch is "OFF," then output line 300 of gate 309 turns on monostable multivibrator S16, pulse S16 being applied through OR-circuit 307 to actuate multivibrator S15, pulse S16 being used for delay purposes only. However, if the switch is in the "ON" state, then output line 302 of gate 309 is employed to actuate monostable multivibrator S17, pulse S17 being applied to a gate 311 (FIG. 17E) to test whether contents of the word counter of audio buffer C are or are not at "6." If these contents are at six, then output line 304 of gate 311 is activated to actuate monostable multivibrator S18, pulse S18 being applied to a flip-flop 313 to switch flip-flop 313 to its "1" state to thereby initiate processing from an audio buffer C. In this connection, the "1" output of flip-flop 313 actuates a gate 315 to effect such initiation. If the contents of the word counter of audio buffer C are not at "6," then output line 306 of gate 311 is actuated to provide a pulse through an OR-circuit 317 to actuate monostable multivibrator S19. Pulse S19 is applied to a gate 319 to test for the state of flip-flop 313, the input lines to gate 319 being the set and reset output lines C and C.

If this test finds that flip-flop 313 is still in its "1" state, then output line 308 of gate 319 is activated to turn on monostable multivibrator S20, pulse S20 being applied through OR-circuit 317 to actuate monostable multivibrator S19, pulse S20 being used for delay purposes only. If the test finds that flip-flop 313 is in its "0" state, then output line 310 of gate 319 is active whereby pulse S21 is applied through an OR-circuit 275 to turn on monostable multivibrator S1 to thereby initiate the sequence cycle for audio buffer A.

It is realized that in this sequence cycle, flip-flop 153 provides the actuating input for gate 151, which controls processing in audio buffer A. Flip-flop 215 provides the actuating input to gate 297, which controls the processing for audio buffer B. Flip-flop 313 provides the actuating input to gate 315, which controls the processing for audio buffer C. Pulses S7, S14 and S21 are utilized to actuate tone generator 303 to provide the beep at the end of a processing cycle at a station.

There are now described the events which ensue during the processing cycle. In this description there are utilized FIG. 17, i.e., central controls, FIG. 5, i.e., the process flow chart and FIG. 18, i.e., the process pulse generator.

It is recalled that the process pulse generator, i.e., the P-clock, is actuated by a pulse on line 316, which turns on monostable multivibrator P1 to produce pulse P1. Pulse P1 is passed through an OR-circuit 401 and applied to gates 151, 297 and 315, the pulse emerging on lines 156, 178 and 200 from gates 151, 297 and 315 respectively, the pulse being transmitted to the read clutch in the particular audio buffer, viz., A, B or C via cables 154, 176 or 198. As each word is read from an audio buffer, the word counter therein is decremented by one. When pulse P1 terminates, it actuates monostable multivibrator P2 through an OR-circuit 405. Pulse P2 is employed to test whether the word counter in the particular audio buffer has been counted down to "3." To this end, pulse P2 is applied to a gate 407, the input lines to gate 407, viz., lines 356 and 358, representing the lines from a word counter in an audio buffer which indicate whether or not the contents of the counter are at "3." If a word counter has not been counted down to "3" at this juncture, an output line 318 of gate 407 is active to turn on monostable multivibrator P3, pulse P3 being applied through OR-circuit 405 to again actuate monostable multivibrator P2, pulse P3 being employed for delay only. However, if the word counter is at "3," then output line 320 of gate 407 is active to turn on monostable multivibrator P4.

The P4 pulse is passed through an OR-circuit 403 to gates 151, 297 and 315, the P4 pulse appearing on either of lines 158, 180 and 202, whereby they are transmitted to audio buffer A, B or C by cables 154, 176 and 198 respectively. At the audio buffer, the P4 pulse is operative to disengage the read clutch.

At this point, the keyboard operator now has to key in the burst of three words to the keyboard. Accordingly, when pulse P4 terminates, it turns on monostable multivibrator P5 through an OR-circuit 409, pulse P5 being applied to a gate 411, the input lines to gate 411 being the lines 228 and 230 from the keyboard. The function of pulse P5 is to ascertain whether stroke counter 243 (FIG. 12) is or is not at "3." If it is not at "3," then output line 322 of gate 411 is active to turn on monostable multivibrator P6, pulse P6 being applied through an OR-circuit 409 to again actuate monostable multivibrator P5, pulse P6 being used for delay purposes. If output line 324 of gate 411 is active indicating that stroke counter 243 is at "3," then monostable multivibrator P7 is switched on, pulse P7 being passed through OR-circuit 401 to gates 151, 297 and 315. Thereby, they procede via cables 154, 176 or 198 to either of audio buffers A, B or C. The function of pulse P7 is to again engage the read clutch in audio buffer and to reset the stroke counter to "0."

When pulse P7 terminates, monostable multivibrator P8 is switched on through an OR-circuit 413, pulse P8 being applied to gate 415, the input lines to gate 415 being 360 and 362 which represent the 0 and 0 output lines of the word counter in an audio buffer. If the contents of a word counter in this situation are not at "0," then output line 326 of gate 415 is active to switch on monostable multivibrator P9, pulse P9 being passed through OR-circuit 415 to again switch on monostable multivibrator P8, pulse P9 being employed for delay purposes. If, however, the word counter is at "0" at this point, then output line 328 of gate 415 is active to switch on monostable multivibrator P10 to disengage the read clutch and to this end, pulse P10 is passed to the read clutch via cables 154, 176 or 198 respectively.

When pulse P10 terminates, it switches on monostable multivibrator P11 through an OR-circuit 417. The function of pulse P11 is to test whether stroke counter 243 in keyboard 235 is at "3." To this end, pulse P11 is applied to gate 419, the input lines to gate 419 being lines 228 and 230, which are the 3 and 3 output lines of stroke counter 243 (FIG. 12). If stroke counter 243 is not at "3," then output line 230 of gate 419 is active to switch on monostable multivibrator P12, pulse P12 being applied through OR-circuit 417 to again switch on monostable multivibrator P11, pulse P12 being used for delay purposes. If, however, stroke counter 243 is at "3," then output line 332 of gate 419 is active to switch on monostable multivibrator P13. Pulse P13 is passed through an OR-circuit 421 to appear on line 224, which resets stroke counter 243 to "0." Pulse P13 is also employed to check compare unit 153 in error detect stage 245 (FIG. 13). To this end, it is applied to a gate 423, the input lines to gate 423 being lines 244 and 246, representing equal and not equal from compare unit 151. If the output from compare unit 151 shows inequality, i.e., the check digit did not compare whereby line 246 therefrom is active, then output line 334 of gate 423 is correspondingly active to switch on monostable multivibrator P14, pulse P14 being used to request an audio response from the audio response unit. To this end, pulse P14 goes directly to the audio response unit. It is also applied to set a flip-flop 358 to its "1" state. Upon the determination of pulse P14, it switches on monostable multivibrator P15 through an OR-circuit 427, pulse P15 being applied to a gate 429, the input to gate 429 being the set and reset outputs of flip-flop 358. If the audio response has not been completed, then output line 336 of gate 429 is active to switch on monostable multivibrator P16, pulse P16 being applied through OR-circuit 427 to again switch on monostable multivibrator P15, pulse P16 being used for delay purposes only. If, however, the audio response has been completed, then output line 338 of gate 429 is active, the pulse on line 338 being passed through an OR-circuit 431 to switch on monostable multivibrator P17. Pulse P17 is employed to reset the A, B and C flip-flops to 0 and also to reset modulo 9 accumulator 149 in error detect stage 245 (FIG. 13). To this end, pulse P17 is transmitted directly to modulo 9 accumulator 149 in error detect unit 245 and is applied as a reset input to flip-flops 153, 295 and 313.

In testing compare unit 151, in error detect unit 245, if it was found that the check digit did compare whereby output line 244 of compare unit 151 is active, then the microprogram branches directly from pulse P13 to pulse P18 by the turning on of monostable multivibrator P18. The function of pulse P18 is to determine whether or not there is a request for a total. To this end, pulse P18 is applied to a gate 439, the input lines to gate 439 being lines 266 and 264 of decoder 253 in random access memory 245 (FIG. 15). If there is a request for a total, then output line 344 of gate 439 is active to switch on monostable multivibrator P19. The function of pulse P19 is to initiate a printout of a total. To this end, pulse P19 is applied to gates 433, 435 and 437. Thereby, pulse P19 is sent to the particular stations A, B or C through output lines 110, 128 and 146 respectively. These lines are in cables 102, 120 and 138. Pulse P19 is also applied to set a flip-flop 360 to its "1" state.

When pulse P19 terminates, monostable multivibrator P20 is switched on through an OR-circuit 441. The function of pulse P20 is to test whether the total printout has been completed. Accordingly, pulse P20 is applied to a gate 443 whose input lines are the set and reset outputs of flip-flop 360. If the total printout is not complete, then output line 346 of gate 443 is active to switch on monostable multivibrator P21, pulse P21 being applied through OR-circuit 341 to again switch on monostable multivibrator P20, pulse P21 being used for delay purposes. If, however, the total printout is complete, then output line 356 of gate 443 is active; and the microprogram branches back to pulse P17, monostable multivibrator P17 being turned on at this juncture through OR-circuit 431.

If pulse P18 ascertained that there is not a request for a total, then output line 348 of gate 439 is active to turn on monostable multivibrator P22, pulse P22 being applied to request a read access from the memory in the random access memory unit 245 (FIG. 15). Pulse P22 is also applied to set to its "1" state a flip-flop 362. When pulse P22 terminates, monostable multivibrator P23 is switched on to OR-circuit 445. The function of pulse P23 is to test the completion of the memory access. Thus, it is applied to a gate 447 input lines to which are the set or reset output lines of flip-flop 362. If the memory access is not complete, then output line 350 of gate 447 is active to switch on monostable multivibrator P24, pulse P24 being used to switch on monostable multivibrator P23 through OR-circuit 445, pulse P24 being used for delay purposes only. However, if the memory access is complete, then output line 352 of gate 447 is active to switch on monostable multivibrator P25. The function of pulse P25 is to gate the price field from the data register 257 in the random access memory 245 (FIG. 15) to the particular accumulator. This is accomplished by applying pulse P25 to gates 433, 435 and 437, the pulse being sent out to the particular station on either of lines 108, 126 or 144 in cables 102, 120 and 138 respectively. Pulse P25 is also applied to set a flip-flop 364 to its "1" state. Pulse P25 also functions to initiate the printout of an item by a line 260 from an accumulator.

When pulse P25 terminates, monostable multivibrator P26 is switched on through an OR-circuit 451, the function of pulse P26 being to test for the completion of the item printout. To this end, it is applied to a gate 453, the inputs to gate 453 being the set and reset outputs of flip-flop 364. If the printout is not completed, then output line 354 of gate 453 is active to switch on monostable multivibrator P27, pulse P27 being used for delay purposes. If, however, the printout is complete, then output line 340 of gate 453 is active to switch on monostable multivibrator P17 through OR-circuit 431.

The following tabulation sets forth the relationship of the operations under the control of the sequence pulse generator (S-clock, FIG. 19). The flow chart for the sequence microprogram is shown in FIG. 4. ##SPC1##

The following tabulation sets forth the relationship of the operations under the control of the process pulse generator (P-clock, FIG. 18). The flow chart for the process is shown in FIG. 5. ##SPC2##

There follows hereinbelow, a tabulation of the cables and their respective lines appearing in the embodiment represented by the block diagram shown in FIG. 3.

designations Cable Numbers of Lines and Connections in Cable Description __________________________________________________________________________ Cable 100 (From Line 100 Microphone station A to audio Output buffer A)

cable 102 (From Line 104 Audio response central controls Line 106 Beep response to station A) Line 108 Print item Line 110 Print total Lines 112 (as Item data many as re- quired)

Cable 114 (From Lines 114 (as Total data accumulators to many as re- station A) quired)

Cable 116 Line 116 Printing com- (From station A to pleted central controls)

Cable 118 (From

Line 118 Microphone output station B to audio buffer B)

cable 120 (From Line 122 Audio response central controls Line 124 Beep response to station B). Line 126 Print item Line 128 Print total Lines 130 (as Item data many as re- quired)

Cable 132 Lines 132 (as Total data (From accumulators many as re- to station B) quired)

Cable 134 Line 134 Printing com- (From central con- pleted trols to station B) Cable 136 Line 136 Microphone output (From station C to audio buffer C)

cable 138 Line 140 Audio response (From central Line 142 Beep response controls to stat- Line 144 Print item tion C) Line 146 Print total Lines 148 (as Item data many as re- quired)

Cable 150 Lines 150 (as Total data (From accumulators many as re- to station C) quired)

Cable 152 Line 152 Printing com- (From station C to pleted central controls)

Cable 154 Line 156 Read engage (From central con- clutch trols to audio Line 158 Read disengage buffer A) clutch

Cable 160 Line 162 Read head output (From audio buffer A Line 164 Word counter out- to central controls) put at "0." Line 166 Word counter out- put at "0." Line 168 Word counter out- put at "3." Line 170 Word counter out- put at "3." Line 172 Word counter out- put at "6." Line 174 Word counter out- put at "6."

Cable 176 Line 178 Read engage (From central con- clutch trols to audio buffer Line 180 Read disengage B) clutch

Cable 182 Line 184 Read head output (From audio buffer Line 186 Word counter at B to central controls) "0." Line 188 Word counter out- put at "0." Line 190 Word counter out- put at "3." Line 192 Word counter out- put at "3." Line 194 Word counter out- put at "6." Line 196 Word counter out- put at "6."

Cable 198 Line 200 Read engage clutch (From central con- Line 202 Read disengage trols to audio clutch buffer C)

cable 204 Line 206 Read head output (From audio buffer Line 208 Word counter out- C to central con- put at "0." trols) Line 210 Word counter out- put at "0." Line 212 Word counter out- put at "3." Line 214 Word counter out- put at "3." Line 216 Word counter out- put at "6." Line 218 Word counter out- put at "6."

Cable 220 Line 222 Headset (From central con- Line 224 Reset stroke trols to keyboard) counter

Cable 226 Line 228 Stroke counter (From keyboard output at "3." to central controls) Line 230 Stroke counter output at "3." Line 232 Accept switch at "Off." Line 234 Accept switch at "On."

Cable 236 Lines 236 Input to modulo (From keyboard to (eight 9 accumulator error detect) lines)

Cable 238 Lines 238 Input to address (From keyboard to (10 lines) assembly register random access memory)

Cable 242

Line 244 Output of compare (From error detect unit is equality to central controls) Line 246 OUt of compare unit is inequality

Cable 248 Lines 248 (as Low order digit (From Random access many as re- of address as- memory to error quired) sembly register detect)

Cable 252 Line 254 Audio response (From audio response completed unit to central Line 256 Actual audio controls) response

Cable 258 Lines 258 (as Input to accumu- (From random access many as re- lators) memory to total quired) accumulators)

Cable 260 Line P25 P25 (From central con- (Pulse P25) trols to accumulators) A flip-flop A B flip-flop B C flip-flop C

cable 262 Line 264 Item (From random access Line 266 Total memory to central Line 268 Read Access controls) Complete. Lines 270 (as Item Data many as re- quired)

Cable 272 S1 "On" status of S1 (From sequence pulse S3 "On" status of S3 generator to central S4 "On" status of S4 controls) S5 "On" status of S5 S7 "On" status of S7 S8 "On" status of S8 S10 "On" status of S10 S11 "On" status of S11 S12 "On" status of S12 S14 "On" status of S14 S15 "On" status of S15 S17 "On" status of S17 S18 "On" status of S18 S19 "On" status of S19 S21 "On" status of S21

cable 274 Line 276 Turn "On" S2 (From central con- Line 278 Turn "On" S3 trols to sequence Line 280 Turn "On" S4 pulse generator) Line 282 Turn "On" S5 Line 284 Turn "On" S6 Line 286 Turn "On" S7 Line 288 Turn "On" S9 Line 290 Turn "On" S10 Line 292 Turn "On" S11 Line 294 Turn "On" S12 Line 296 Turn "On" S13 Line 298 Turn "On" S14 Line 300 Turn "On" S16 Line 302 Turn "On" S17 Line 304 Turn "On" S18 Line 306 Turn "On" S19 Line 308 Turn "On" S20 Line 310 Turn "On" S21

cable 312 P1 "On" status of P1 (From process P2 "On" status of P2 pulse generator P4 "On" status of P4 to central con- P5 "On" status of P5 trols) P6 "On" status of P6 P7 "On" status of P7 P8 "On" status of P8 11 P9 "On" status of P9 P10 "On" status of P10 P11 "On" status of P11 P13 "On" status of P13 P14 "On" status of P14 P15 "On" status of P15 P17 "On" status of P17 P18 "On" status of P18 P19 "On" status of P19 P20 "On" status of P20 P22 "On" status of P22 P23 "On" status of P23 P25 "On" status of P25 P26 "On" status of P26

cable 314 Line 316 Turn "On" P1 (From central con- Line 318 Turn "On" P3 trols to process Line 320 Turn "On" P4 pulse generator) Line 322 Turn "On" P6 Line 324 Turn "On" P7 Line 326 Turn "On" P9 Line 328 Turn "On" P10 Line 330 Turn "On" P12 Line 332 Turn "On" P13 Line 334 Turn "On" P14 Line 336 Turn "On" P16 Line 338 Turn "On" P17 Line 340 Turn "On" P17 Line 342 Turn "On" P18 Line 334 Turn "On" P19 Line 346 Turn "On" P21 Line 348 Turn "On" P22 Line 350 Turn "On" P24 Line 352 Turn "On" P25 Line 354 Turn "On" P27 Line 356 Turn "On" P17

cable P14 P14 Request audio (From central con- response trols to audio response unit)

Cable P17 P17 Reset modulo 9 (From central con- accumulator trols to error detect)

Cable P22 P22 Request read (From central con- access trols to random access memory)

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.