US3922649A

US3922649A - Watchman{3 s tour recording system

Info

Publication number: US3922649A
Application number: US504765A
Authority: US
Inventors: Richard J Thome
Original assignee: Merck and Co Inc
Current assignee: Merck and Co Inc
Priority date: 1974-09-10
Filing date: 1974-09-10
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25

Abstract

A watchman''s tour recording system which includes a watchman''s unit having a clock and a clock signal producing means, a station identification signal producing means, a signal memory and means for directing associated clock and station identification signals to corresponding locations in the signal memory when a watchman connects the unit to each check station along a predetermined tour route. At the end of the tour the unit is connected to a computer terminal and its signal memory is read out into the computer. In this way errors made during the tour, such as stations checked too early, too late, in improper order, or not checked at all, are noted.

Description

United States Patent Thome Nov. 25, 1975 [5 WATCHMAN'S TOUR RECORDING 3.371.349 2/[968 Schinner 340/300 SYSTEM 3,736,561 5/1973 Rumpel 340/[47 {75] inventor: Richard J. Thome, Cranford, NJ. Primary Emminer -I-erre Fears [73] Assignee: Merck & Co., Inc, Rahway, NJ, Attorney, Agent, or FirmHarry E. Westlake, Jr; [22} F] d S t 10 1974 Rudolph J. Anderson, Jr.; Francis H. Beef 1 e ep [2l] Appl. No: 504,765 [57] ABSTRACT A watchmans tour recording system which includes a 52 11.5. c1 340/173 R; 340/306; 340/309.1; bah-mg a clock signal 9 346/59 ducmg means, a station identification signal producmg 511 1m. (:1. GllC 13 00 F Signal memory W"? d [58] Field of Search H 340/173 R 306 309' l, c1ated clock and station identification signals to corre- 346/59 sponding locations in the signal memory when a watchman connects the unit to each check station [56] References Cited along a predetermined tour route. At the end of the tour the um! 15 connected to a computer termmal and UNITED STATES PATENTS its signal memory is read out into the computer. In this Chase 1 1 i 1 i i way s 'rors made during the tour uch as tations n m checked too early, too late, in improper order, or not U6 er i 2,734,791 2/l956 lmm 1. 346/[7 checked at are noted 3,237,183 2/[966 Eagan 340/306 24 Claims, 13 Drawing Figures 57407 My l9} 7 01/9 0 @MPr/IE 09m flwnso 0K O O mum flus l m flmm '6 5m 75902 y 754mm 22 lb 24 0/9 fKbfflG' fi wrow 0/- l 1 1 1 I &4 PW? US. Patent Nov. 25, 1975 Sheet20f7 3,922,649

U.S. Patent Nov. 25, 1975 Sheet4of7 3,922,649

Nov. 25, 1975 Shest 6 of 7 3,922,649

US. Patent WATCI'IMANS TOUR RECORDING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to security systems and more particularly it concerns novel arrangements for recording and checking security tours made by watchman.

2. Description of the Prior Art In carrying out security checking operations in factories or other commercial establishments, watchmen usually follow a prearranged tour so that critical areas are checked at predetermined intervals and so that a complete coverage of the premises can be ensured. It is important for insurance and other purposes to have a record made of the watchmans tour. In the past this was obtained by providing the watchman with a selfcontained recording unit which included a clock and a disk shaped paper which was rotated by the clock. The recording unit was "punched" or connected to special station keys at preselected locations along the watchman's tour. As each punch was made, the key would make an impression on the paper disk. This impression was in the form of a symbol which corresponded to the identity of the station; and the location of the symbol on the disk, which was rotated by the clock, would correspond to the time that station was checked. After the tour had been completed, the paper disk would be removed from the unit and replaced by a new one. By noting the symbols and their locations on the disk, it was possible to ascertain what stations were checked and at what times and in what order they were checked.

While this system provided a permanent record of the watchmans tour, it was limited, from a practical standpoint, to relatively simple tours involving a small number of stations. Where a greater number of stations are involved the process of checking the recorded disks becomes very time consuming and subject to error. Also, the system does not lend itself to the checking of multiple tours, nor is it readily adaptable to tour modifications.

It has been proposed to utilize electronic means and a computer system to overcome the above described limitations of the conventional watchmans clock system. Such proposals are found, for example, in US. Pat. Nos. 1,919,007; 2,275,981;2,308,l98; 2,734,791; 3,237,183; 3,371,349 and 3,736,561. These electronic means, however, involved the wiring of each station to be checked to a central computer. While these electronic systems would produce an instantaneous computer readable indication of each station check made by a watchman, they suffer from the disadvantage that the wiring involved makes them quite expensive. Also, a wired system does not lend itself to that type of tour modification which involves relocation of check stations.

SUMMARY OF THE INVENTION The present invention overcomes these difficulties of the prior art. With the present invention it is possible to provide one or several tours covering a great number of stations; and these tours may be reported and checked accurately and rapidly with computer means. Moreover, with the present invention no special wiring is required between the individual stations and a central location. It is also possible with the present invention to relocate check stations with a minimum of difficulty.

According to the prcsent invention there is provided a tour recording arrangement which is carried in a watchmans unit. This tour recording arrangement in cludes a clock signal producing means. a station identification signal producing means, a signal storagc or memory device and means for dirccting corresponding clock and station identification signals to particular 10 cations in the memory device each time the watchman connects the unit to a station being checked. Unlike the clock rotated paper disc units of the prior art, the clock signals in the present invention are recorded as actual data in predetermined locations in the memory device. Thereafter, at the end of a tour the watchmans unit may simply be plugged into a terminal and the data stored in its memory device can be read out to provide a complete, accurate and instantaneous report of the tour along with an indication of missed or improperly checked stations or stations checked at the wrong time.

According to one embodiment, the station identification signals direct the clock signals to corresponding locations in the memory device. In another embodi ment, the memory device is of sufficient capacity to rcceive and store both clock signals and station identification signals. In this second embodiment there are provided sequencing means which, upon each station check, directs the station identification and clock signals to corresponding locations in the memory device. It will be appreciated that this arrangement requires no special wiring between the stations and a separate computer. Further, this arrangement allows tour changes to be made without adjustments either to the stations themselves or to the watchmans unit, Also, if desired, individual check stations can be relocated with a minimum of difficulty since no rewiring is necessary.

In a preferred embodiment, signals representative of station identification and time data are supplied to various memory units in a manner which permits maximum use of the storage capacity of the units. More particularly the storage unit address means are scanned in synchronism with registers containing station identification and time data words; and means are provided to continue the storage scan while the registers are scanned repeatedly as successive station checks are made.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may better appreciated. There are, of course, additional features of the invention that will be described more fully hereinafter. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the basis of the designing of other methods and structures for carrying out the purposes of this invention. It is important, therefore, that this disclosure be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Several embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings forming a part of the specification, wherein;

FIG. I is a diagrammatic representation of a watchmans tour route in which the present invention is utilized;

FIG. 2 is a block diagram showing a computer, computcr terminal and watchmans unit in which the present invention is embodied;

FIG. 3 is an enlarged perspective view ofthe exterior of the watchmans unit of FIG. 2;

FIG. 4 is a fragmentary perspective view showing a check station along the tour route of FIG. 1;

FIG. Sis a cutaway view showing the interior configuration of a station key forming one portion of the check station of FIG. 4;

FIG. 6 is a schematic and block diagram showing the various interior components of the watchmans unit of FIG. 3;

FIG. 7 is a further schematic and block diagram illustrating in greater detail a memory or storage arrangement forming one of the interior components of the watchmans unit of FIG. 6;

FIG. 8 is a diagrammatic representation of a memory unit forming one portion of the diagram of FIG. 7;

FIG. 9 is a view similar to FIG. 6 but showing an alternate internal configuration of a watchman's unit ac' cording to the present invention;

FIG. 10 is a perspective view of a watchmans unit for use with the present invention and employing photoelectric station identifying means;

FIG. II is a partially exposed perspective view showing the exterior ofa station to be checked by the watchman's unit of FIG. I0;

FIG. 12 is a partially exploded perspective view showing the interior of the station of FIG. 11; and

FIG. 13 is a block diagram showing the interior arrangement of components in the watchman's unit of FIG. I0.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I, a premises to be protected is indicated schematically by an outline I0. Within the premises there is provided a terminal station 12 from which various guard tours start and end. Also within the premises are several check stations 100-113. The number and location of these stations is preselected in accordance with the particular security requirements of the premises.

In conducting a tour, a watchman begins at the terminal station 12; and then he walks along a preassigned route. as indicated by the dashed lines I3, to preseleeted check stations. At each station the watchman connects a station key to a watchman's unit which he carries with him. This provides a recording in the watchmans unit of the time of each check which he makes. along with a corresponding identification of the station checked.

The number of stations to be checked in each tour, the order in which stations are checked and the times they are to be checked is established before the watchmans tour begins. For the purpose ofmaximizing security within the premises, the tour routes are changed periodically. It is the ability to adapt to various tour changes which constitutes one important feature of the present invention.

Upon completion of his tour the watchman returns to the terminal station 12 where, as shown in FIG. 2, there is provided a terminal board 14 having a connector plug 16 thereon. A watchmans unit I8 is shown connected to the terminal board 14 via the connector plug 16. When the watchman completes his tour he connects his unit 18 to the terminal board 14; and the data representative of the stations checked and the time of each check made during the tour is fed from the watchmans unit I8 into the terminal board I4. The terminal board 14 is shown to be connected via a cable 19 to a central computer 20. This computer may be remotely located or it may be located at the terminal station 12. A tour storage bank 22 is provided in association with the computer 20. The tour storage bank 22 contains information representative of the stations to be checked for each of several predetermined tours. The tour storage bank 22 may form an integral part of the computer 20 itself. When a watchmans unit 18 is connected to the terminal board 14 to feed actual tour data through the board into the computer 20, ideal data for that particular tour is also fed into the computer from the tour storage bank 22. The actual tour data and the ideal tour data are compared in the computer and any discrepancies which exist are noted and reported. This report may take the form of a printout at the terminal board I4 as indicated at 24 in FIG. 2.

The watchmans unit 18 is a small electronic device which, as shown in FIG. 3, externally resembles a small portable radio. The unit is provided with a terminal connector slot 26 and a station connector slot 28 into which various plugs, such as the connector plug I6 on the terminal board 14 and corresponding plugs at the various stations -113 are inserted for reading data into and out from the unit. The unit I8 is also provided with a switch dial 30 which may be turned to any of several positions corresponding to different tours to which the unit may be assigned. A tour identification number, corresponding to the setting of the dial switch 30 appears at a window 32 at the side of the unit. An operation light 33 is also provided on one side of the unit 18 to indicate when data transferred into or out from the unit is complete.

In carrying out a tour, a watchman proceeds from the terminal station I2 and follows a route corresponding to the tour to which his unit I8 has been set. This tour requires that the watchman be present at particular ones of the check stations I00-ll3 at predetermined times. The presence of the watchman at each station is recorded in his unit when he inserts a station plug into the station connector slot 28 of the unit 18.

A typical check station arrangement is shown in FIG. 4. The check station is provided with a station plug 34 which is anchored, by means of a chain 37 to a post 38 or other structural member on the premises. The station plug 34 includes a projecting card like connector member 36 along one edge of which are provided a plurality of electrical contacts 380-381. When the connector member 36 is inserted into the station connector slot 28 of the watchmans unit 18, the contacts 38 make connection to corresponding contacts (not shown) lo cated within the unit. Inside the connector member 36, various ones of the electrical contacts 38 are connected to each other while other contacts have no connection. This provides a code which identifies the particular station. As can be seen in the cutaway view of FIG. 5, the outermost contacts 38a and 38j are connected to a common base strip 40. These outer contacts provide no part of the station code but instead they provide battery connections as will be described more fully hereinafter. As shown, selected ones of the other contacts. namely the second, 38b, the fifth, 38a, and the sixth. 38]", are each connected to the base strip 40. These contacts represent, respectively, a binary I. a binary 8 and a binary I6, so that together they represent the binary form of the number 25 which constitutes the identification of the station. Other stations, of course, will have other groups of their contacts 38 connected to the base strip 40. With the eight contacts 38b. 381', being available for binary coding, a total of 256 different station codes are available. A greater number may be provided by increasing the number of contacts. It should be noted that other means of producing coded signals may be substituted; for example the connector member 38 may be provided with spaced apart segments of magnetic material and the watchmans unit may be provided with magnetic sensing means.

As indicated above. the watchmans unit 18 records the time of checking of each station along the watchmans tour. Data representative of the time of checking is provided by means of a clock arrangement carried in the watchmans unit.

The general interior composition and arrangement of the watchmans unit 18 is illustrated schematically in FIG. 6. As can be seen, the unit includes a memory 50, a clock 52 for supplying time data to the memory and a station signal receiving means 54 for supplying station identification data to the memory. Electrical power is supplied by a self contained battery (not shown) to which various B and ground connections are made.

The clock 52 is a crystal controlled oscillator which operates at a frequency of 32,768 Hz. The clock output is connected to a fourteen stage binary counter 56 which divides down the clock frequency to l Hz, i.e., one pulse per second. The output of the counter 56 is supplied to a six stage second binary counter 58 which divides the clock frequency down even further to one pulse each 2.12 minutes. These pulses are supplied to an eight stage binary register 60. The stages of this reg ister are connected to eight corresponding time data input terminals 62a-62h of the memory 50. The count condition of the register 60 changes each 2.12 minutes; and since an eight stage binary register is capable of accumulating a total of 256 counts, the clock and memory system is capable of providing time data to the memory 50 in 2.12 minute increments over a total duration of approximately nine hours. The number of increments and the total duration may be increased by increasing the size of the memory and by decreasing the number of counter stages.

The clock arrangement measures elapsed time from a given point, usually the start of a tour. This point in time is established by having the binary register cleared at the start of the tour. A clear signal is applied from the terminal board 14 to a reset terminal 60a to hold the register cleared until the unit is removed from the terminal board to start the tour.

The station signal receiving means 54 includes a plurality of electrical contacts 63a 63j, which, when a station connector member 36 (FIG. 4) is inserted into the station connector slot 28 (FIG. 3) of the unit, make contact with corresponding ones of the connector contacts 38a 38]. The outermost contacts 63a and 63j are connected. respectively, through a first resistor 64 to B", and to ground. The intermediate contacts 63b 631' are connected through associated voltage control resistors 66b 66: to B". Each of the intermediate contacts 63b 631' is also connected via associated station address lines 68b 681' to corresponding station address input terminals 70b 70: of the memory The outermost contact 63a is also connected to the input of a first monostable multivibrator 72. The output of this multivibrator in turn is connected to the inputs of second and third monostable multivibrators 74 and 76. The output of the second multivibrator 74 is con nected both to the base of a control transistor 78 and to a reset terminal 80 of the first monostable multivibrator. A light emitting diode 82 is connected in series with the emitter and collector terminals of the control transistor 78 between B" and ground. The light emitting diode forms the operation light 33 (FIG. 3) of the watchmans unit. The third monostable multivibrator 76 is connected to a write input terminal 84 of the memory 50.

The first monostable multivibrator 72 responds to a decrease in voltage at the first contact 630, which occurs upon connection to a station connector 36, to pro duce a rather short output pulse, e.g., of l0l5 milliseconds. The purpose for this pulse is to cause a time delay sufficient to allow settlement of all transients which occur upon making connection to the station connector 36. The second and third monostable multivibrators 74 and 76 both respond to the trailing edge of the pulse produced by the first monostable multivibrator 72. The output of the second monostable multivibrator 74 is also in the form of a pulse but this pulse lasts for a much larger period of time, e.g., [5 seconds. This pulse maintains the first monostable multivibrator 72 in its reset condition so that a double reading will not be fed into the memory 50 if the connector contact is broken and reestablished more than once while a station is being checked. In normal use the connector 36 will be removed well in advance of the 15 second delay interval; and yet this delay interval should expire long before the watchman reaches a subsequent station for taking a new reading.

During the pulse output interval of the terminal monostable multivibrator 74 the control transistor 78 is maintained conductive so that current flows through it and through the light emitting diode 82 causing it to illuminate and signal the entry of data into the memory 50.

The trailing edge of the output pulse from the first monostable multivibrator 72 also triggers the third monostable multivibrator so that it produces a short gating pulse which is applied to the memory 50. This pulse allows information which is present at the time data input terminals 620 62h to be fed into the memory at locations corresponding to the data present at the station address input terminals b 70i of the memory 50.

In summary, it will be seen that with the trigger arrangement described above, a reading is taken by in serting a connector 36 into the unit to trigger the monostable multivibrators 72, 74 and 76 in a particular sequence so that a write input terminal 84 of the memory 50 is energized a short time following insertion of the connector. Also, during this time the light emitting diode is illuminated to show that the reading is being taken.

During the taking of each reading. a different combination of time signals and station signals is present at the

terminals

62 and 70 of the memory 50. These time signals are directed into the memory in accordance with their associated station signals, so that the time each station was checked can be read out after completion of a tour. Thus, at the end of a tour there will be stored in the memory 50 as many time signals as the number of stations checked in a tour. The memory 50, having eight address input terminals 70b 701', is ca 7 pable of accepting as many as 256 different binary signal combinations which corresponds to a total of 256 different stations In an actual tour, substantially less than this number of stations would be checked.

At the end of the tour, the watchmans unit 18 is re turned to the terminal station 12 and is connected to the terminal board I4 by inserting its connector plug 16 into the terminal connector slot 26 ofthe unit. The terminal connector plug I6, which is represented schematically in FIG. 6 has terminal connectors 86 which contact corresponding connectors 88 in the unit. A first group of these connectors 880 are connected via switches 90 which are opened and closed by operation of the switch dial 30. The particular combination of these switches which are closed corresponds to the identification number of the tour just completed; and this information is read into the terminal board 14 and the computer 20 so that a corresponding ideal tour will be selected from the tour storage bank 22 for comparison in the computer with the data to be read out from the watchmans unit. A second group of connectors, 88b, is connected to the station address input terminals 70b .701' ofthe memory 50 to apply interrogation signals from the computer to the memory 50 for reading its contents in prescribed fashion into the computer. A third group of connectors 886 is connected to time data output terminals 92a 4 92h of the memory 50. These last mentioned terminals correspond respectively, to the time data input terminals 62a 62h of the memory and they become energized in accordance with the energization of their respective data input terminals when interrogation addresses from the terminal board are applied in the same manner as the station address signals when the unit was connected to a particular station. A writeout connector 88d is connected to the write input terminal 84 to receive signals from the computer which cause writeouts from the memory to be transferred to the computer at proper times.

The computer 20 is set up using known techniques to interrogate the memory 50. In doing this the computer presents in succession signals corresponding to the identification of the different stations along the tour which has been completed, These signals are applied to the address input terminals 70b. 70i. A writeout signal is also applied via the contact 88d and the write input terminal 84 and the memory 50 then presents the stored time data corresponding to each identified station. This information, which appears at the data output terminals 92a 92h is then compared in the computer with corresponding information supplied from the tour storage bank 22. Any discrepancies noted by the computer are then identified and reported on a printout or in any other desired manner.

In the arrangement of FIG. 6, the station identification signals supplied to the terminals 70 of the memory 50 serve to direct the time data signals present at the terminals 62 to particular locations in the memory. This may be carried out with the arrangements shown in FIGS. 7 and 8. As shown in FIG. 7, the memory 50 includes eight memory units 50a 50h. Each of the station address input terminals 70b 701' is connected to a corresponding location on each of the memory units 500 50h. Thus, whenever a station idcntifica tion code is present on the station address lines 68!: 68i (FIG. 6) this same code is applied in the same manner to each of the memory units 50a 50h.

Each of the memory units 500 i 50h is also connected to a different one of the time data input termimils 62H 6211. Thus while each of the memory units 50a 50h receive the same station lt i "with ittion sig nals they each receive a different portion of the time signals.

The write input terminal 84 is also connected to write terminals 840 i 84/1 on each of the lilLlll nits 50a 50h. Also each of the memory units 50a 5011 is connected to a different one of the time data output terminals 920 92/: for readout to the computer.

FlG. 8 shows, by way of example, one form of meniory unit which may serve as one of the memory units 50a. 50h. As shown in FIG, 8 there are provided first and second four stage binary decoders 200, 20.1 The first four station address input terminals "b, 70c. 70d and 702 are connected as inputs to the first decoder 200 while the second four station address input termi nals 70f, 70g, 70h and 701' are connected as inputs to the second decoder 202. Each decoder is capable of responding to each possible combination of binary input signals at its input terminals to energize a different one of sixteen output terminals 204. Memory lines 206 estend in parallel fashion from each of the terminals 204, with those from the first decoder 200 being arranged at right angles to those of the second decoder 202. This arrangement provides a matrix of 256 different line in tersections; and for each overall combination of binary signals applied to the two decoders 200, 202 a particular one of the hoizontal lines and a particular one of the vertical lines 206 are energized and their mutual intersection is made receptive to retention or memory of applied input signals. A read'write line 208 extends diago nally over the memory matrix crossing each of the 256 intersections in succession. This read-write line is con nected both to one of the time data input terminals 62 and the one of the data output terminals 92. A gate 210 is interposed in the read-write line 208. This gate has one input connected to the write input terminal 84 to prevent time signals from being applied to the memory unit until a write signal is applied.

Memory means (not shown), such as magnetic ferrite cores having high hysteresis characteristics, are provided at each intersection defined by two of the memory lines 206 and the read-write line 208. Whenever the three lines defining an intersection are simulta neously energized, the memory means changes its state or condition; and it retains its new state or condition after any or all of the memory lines and read-write line are deenergized. Additional means (not shown) may he provided for deenergizing the memory means to clear the unit between uses.

It is to be understood that the particular memory arrangement illustrated in FIG. 8 is shown only by way of example only and that other units capable of storing bit data at various locations therein, can be substituted.

With the memory arrangement of FIG. 7 it will be seen that as each station is checked. the station identification signals produced by the station connector serves to direct the time signals then oceuring to particular lo cations within the group of memory units 50a 50):. The same memory unit may also store time signals for each of the other stations, Since each unit is provided with 256 different locations for receiving time signals a total of 256 different station checks may be recorded in the eight memory units.

Upon completion of a tour the watchmans unit is read out into the computer by applying different station signal codes successively to each of the memory units 500 i @50h; and. during the application ofeaclt station signal code, applying a signal to the write input terminal 84. If one or more of the memory units 500 50h has an energized memory element at the intersection or bit location therein corresponding to the applied station signal code. a signal will be produced at the data output terminals 92 of that particular unit. Meanwhile no signal will be produced at the corresponding data output terminals of the other units. Thus by successively applying interrogation signals corresponding to all of the stations, the particular stations which were checked and the time of each such check will be identified by the computer.

It will be appreciated that the system of FIGS. 6-8 makes use of station identification signals as address means to direct the time signals into different locations in the memory. For some applications it may be prefer able to provide a memory into which the time signals and the corresponding station identification signals are both supplied to a memory as stored data. In such case each stations identification signal would be stored in the memory alongside a corresponding time data signal which occurred when the station was checked.

FIG. 9 shows an arrangement for storing both time and station identification signals as data into a memory. As shown in FIG. 9, there is provided a two hundred fifty six by sixteen bit memory 300. This memory is similar to that of FIG. 8 except that it comprises sixteen memory units each having eight address terminals. Eight of the memory units store the different bits of eight bit time data words while the other eight units store the different bits of eight bit station identification data words. Time data word signals are provided by a clock 302 whose output pulses are divided by first and second binary counters 304 and 306. The divided pulses from these counters are supplied to an eight stage binary register 308 as in the preceeding embodiment; and the outputs from each stage are supplied to corresponding time input data terminals 310a .310h, shown on the upper right hand side of the memory 300. These terminals are connected as data inputs to eight memory units similar to the memory units of the preceeding embodiment.

Station identification signals are applied from a station key 312, as in the preceeding embodiment and these signals, which are also in binary digital form, are applied to corresponding station identification input terminals 314a 3l4h, shown on the upper left hand side of the memory 300. The station identification signals may be generated as in the preceeding embodiment. Thus as shown in FIG. 9 there is provided a common B connection via individual resistors 316 to corresponding lines 318 interconnecting the various terminals 314a 314/1 to associated station key contacts Address signals are produced each time a connection is made to a station key. These address signals serve to direct both the time data input signals and the associated station input signals to corresponding locations in the memory 300. As shown in FIG. 9, an additional resistor 320 is connected between B and a station key contact 320a. A trigger line 324 extends from a junction between the resistor 320 and the contact 3200. to a first monostable multivibrator 326. The first monostable multivibrator is connected to second and third

monostable multivibrators

328 and 330. As in the preceeding embodiment the first monostable multivibrator 326 provides a short delay so that electrical transients, which occur when a station key is connected to the unit. can expire. Thereafter, the trailing leg of the output signal of the first monostable multivibrator 326 triggers both the second and

third multivibrators

328 and 330. The second multivibrator 328 produces a first 5 output which lasts for about fifteen seconds. and thereafter it produces a second output. The first output is fed back to a reset terminal 332 of the first multivibrator 326 to hold that multivibrator in its reset condition thereby preventing it from responding to subsequent inputs during the fifteen second interval. The first out put from the second multivibrator 328 is also applied to the base terminal of a control transistor 333 connected in series with a light emitting diode 334 between 8 and ground. This causes the light emitting diode to illuminate while the time data and station identification signals are being entered into the memory. At the end of the fifteen second interval. i.e., after data has entered the memory 300, a second output from the second monostable multivibrator 328 is applied to a binary address register 336. This register has a plurality of stages each connected via an address control line 3380 338k to a corresponding address input terminal 340a 340h of the memory 300. Upon completion of time and station data entry into the memory 300, the second output from the second monostable multivibrator 328 causes the binary address register to energize a new combination of its address control lines 338a 33811. These signals control the address portion of the memory 300 so that the next subsequently applied data input signals will be directed to different locations in the memory.

The actual application of data input to the memory 300 is controlled by the third monostable multivibrator 330 which applies a write" pulse of short duration to a write input terminal 342 ofthe memory in response to the trailing edge of the pulse from the first multivibrator 326.

It will be appreciated from the foregoing that while a larger number of memory units is employed in the arrangement of FIG. 9 than is required in the arrangement of FIGS. 6 and 7 for a corresponding number of time and station possibilites, it is possible with the arrangement of FIG. 9 to use memory units of smaller capacity. This is because in most situations a watchman would be expected to make much less than 256 different station checks during a tour. In the more usual situation. where less than 64 different checks are to be made. the sixteen memory units of the memory 300 would only need to have bit capacities of 64. In such case the binary address register would have to have only six different stages rather than the eight stages indicated in FIG. 9.

A further feature of the memory arrangement of FIG. 9 is that it permits the unit to record successive checks of the same station at different times during the course of a tour. This is achieved by virtue of the fact that each check made opens a different location in the memory for receipt of both station identification and time data; and identical station identification data can therefore be accomodated in the different locations of the memcry.

The arrangement of FIG. 9 is accomodated for reading recorded data into the terminal board 14 (FIG. 2) in the same manner as in the preceeding embodiment. Thus there is provided a plurality of address interrogation contacts 344a 344 connected, respectively, to the address input terminals 340a 340h to receive interrogatogation signals from the computer. There is also provided a plurality of station data output tcrmi nals 346a 346k and a plurality of time data output terminals 348a 3481': connected. respectively. to corresponding contacts 350a 3501i and 352a 352k for transferring recorded time and station identification data into the computer from those locations in the memory corresponding to the particular address interrogation signals applied to the memory from the computer. The actual readout of data is controlled by a write" signal from the computer applied through a write input terminal 354 to the write input terminal 342 of the memory.

Reset pulses are applied from the terminal board 14 (FIG. 2) through a reset terminal 356 to both the binary register 308 and the binary address register 336. These pulses are applied to the unit upon the start of each tour so that the production ofelapsed time signals will coincide with the start of the tour and so that the address portion of the unit will be set to insert the data from the first station check into the first memory location.

The unit of FIG. 9 is also provided with tour indication switches 358 which are set in accordance with an assigned tour and which, when connected to the terminal board 14. serve to provide signals to the computer for indentifying the tour plan for which the data in the memory should correspond.

FIGS. 10-13 show a modified version of a watchmans unit and check station which has been designed for commercial application. This modified version. which is described and claimed in a copending application. Ser. No. 504,764 filed Sept. I0. 1974 in the name of W. G. Lawrence. et al. differs from the above described versions. firstly in that it employs photoelectric means for generating station identification signals, and secondly, in that it employs memory units in a novel arrangement so that for certain applications their storage capabilities may be utilized more fully and more efficiently than in the preceeding embodiments.

In FIG. 10 there is shown a watchman's unit 400 whose external configuration is similar to that of the preceeding embodiment. In the present embodiment however there is provided a station key slot 402 at the lower end with a light source 404 extending along one side of the slot and a plurality of photocells 406 distributed along the other side. A switch (not shown) is arranged near the bottom of the slot to turn on the light source 404 when a station key is inserted into the slot 402. A guide lug 410 is also provided near the lower edge of the unit to prevent improper placement of station keys in the slot.

A similar key slot 411 is provided at the upper end of the device for connection to a terminal board at the end of each tour.

FIG. 11 shows a station key arrangement for checking by the watchman's unit 400. This station key arrangement comprises a base plate 412 having holes 414 near each end through which bolts or rivets 416 pass to anchor the arrangement to a structural member or other solid anchor means at a predetermined location in the premises to be checked. A box-like housing 418 is attached to the base plate 412. This housing is opened at the top and is shaped to allow the lower end ofthe watchmans unit 400 to fit down into it. The front side of the housing 418 is notched at 419 to accomodate the guide lug 410 of the watehmans unit. An identification numeral may be printed on the front of the housing for visual identification of the station.

FIG. 12 shows a station connector assembly 420 which fits into the bottom of the boxlikc housing 418 of FIG. 11. The connector assembly 420 includes a horizontal bottom plate 422 which fits up against and closes the bottom of the housing 418. The bottom plate 422 is held in place by means of screws 424.

A card like connector element 426 extends upwardly from the center of the bottom plate 422 within the housing 418. As shown in FIG. 12 this connector element is provided with a series of spaced apart holes 428, some of which are filled with a light transparent substance and others of which are filled with a light opaque substance. The particular arrangement of light transparent and light opaque holes forms a binary coding arrangement which identifies the station.

The coding arrangement of the connector element 426 is not readily visible so that it is not susceptible to counterfeiting should a watchman wish to enter false data into the recorder unit. In addition the particular code for the station may be changed by removing the bottom plate and connector unit and replacing it with a new one. A wire 429 may be passed through holes in the screws 424 and fastened with a seal 430 to prevent surreptitious removal of the bottom plate and connector element.

In making a station check. the watchmans unit 400 is fitted into the box-like housing 418 at the station so that the connector element 426 fits into the station key slot 402. When this occurs, the light source 404 is switched on. Light from the source 404 passes through those holes 428 of the connector element which are selectively fitted with a light transparent substance to energize the photocells 406 which are adjacent the light transparent holes. Those photocells which are adjacent the light opaque holes do not become energized. The pattern or arrangement of electrical outputs from the energized and non energized photocells corresponds to the station code; and this output is used for "data re cording in the watchmans unit.

FIG. 13 shows in block diagram form an alternate ar rangement of components within the watchman's unit. In the arrangement of FIG. 13 both station identifica tion and time data signals are inserted into particular memory locations; however the full capacity of only four 256 bit memories is utilized in the recording of 64 station checks. Also with the arrangement of FIG. 13, the same station may be rechecked at different times during a tour and each check will be properly and unambiguously recorded in the storage means.

As shown in FIG. 13, there are provided four 256

bit memory units

440, 442, 444 and 446. Each memory unit includes eight address terminals 448:: 448k which control, according to the arrangement of signals applied thereto, the locations within the unit where data information is stored.

Station identification information is generated in binary coded digital form upon the connection of the watchmans unit to check station as described above. This information is presented in binary digital form at various outputs 450b 450i of an input transducer 452. This transducer may, for example, include the photocells 406 of FIG. 10. The outputs from the transducer 452 are arranged into two groups 450b 450a and 450f. 450i and are supplied. respectively, to bit

select units

454 and 456. These bit select units each have two

address terminals

458a and 458b, and, depending on the particular arrangement of binary signals applied to these address terminals. the

bit selection units

454 and 456 will permit a different one of the applied outputs 450 to pass through to a single data input line 454a and 456a respectively. Actually, as will be seen, the binary signals are binary forms of successive counts from one to four so that the bit selections scan the outputs 450 and successively pass each of them through the selectors to their single output. The data input lines 454a and 4560 are connected to

data input terminals

466 and 468 of the two

memory units

440 and 442.

Time data information is generated by means of a clock 470 which generates a continuous series of accurately spaced impulses. A binary counter or Count Down Circuit" 472 receives these pulses and produces a predetermined submultiple thereof. These divided down pulses are applied to a time counter 474, which may be a multiple stage binary register or accumulator having a plurality of output terminals 476a 476k. The pattern of energization of these terminals, as in the preceeding embodiments, represents the total accumulated pulse count from the divider 472; and this in turn corresponds to the elapsed time since the clearing of the time counter 474. The first four terminals 476a 476d are connected to a third bit select unit 478 while the second four terminals 476e 476k are connected to a fourth bit selector unit 480. These two bit selector units operate in the same manner to direct different ones of their applied signals through them to single

output data lines

478a and 480a in accordance with binary signals applied to address

terminals

458a and 458b thereon. These data lines are connected respectively to data input terminals 481 and 482 of the

memory units

444 and 446.

The eight address terminals 448a 448k of the

memory units

440, 442, 444 and 446 serve to direct data signals from the

bit selection units

454, 456, 478 and 480 to particular ones of the 256 different locations within the memory units.

Corresponding ones of the address terminals of each of the memory units are connected to an associated output terminal 484a 484k of an address counter 486. This address counter has an input terminal 488 connected through a clock gate 490 to the clock 470. As clock signals pass throughthe gate 490 they are accumulated in the address counter 486 and cause its output terminals 484a 484h successively to change the pattern of their energization, thereby successively changing the bit locations within the

memory

440, 442, 444 and 446 which can receive and store data input signals. The address counter 486 is arranged to count in conventional binary form with the first terminals 484a corresponding to the least significant digit and the last terminal 484 corresponding to the most significant digit. The two least significant digit output terminals 484a and 484b of the address counter 486 are connected to

corresponding address terminals

458a and 458b of each of the four

bit selector units

454, 456, 478 and 480. It will be appreciated that as successive pulses are applied to the address counter 486 to step it through a complete address count sequence, the bit selectors, which are ofa much smaller count capacity. recycle, i.e scan through their selection range successively a number of times. It will further be appreciated that the address counter with its eight output terminals can produce a total of 256 different addresses, corresponding to the number of bit locations in each of the

memory units

440, 442, 444 and 446. The

bit selector units

454, 456, 478 and 480, on the other hand, are capable of accumulating only four counts, to direct their four applied inputs in succession to their single output. Thus, as 256 clock pulses are applied successively to the

address counter

486, 64 four bit words are successively transferred from the station identification input transducer 452 and the time counter 474 into each of the various memory units. Actually, the two

memory units

440 and 442 cooperate by storing different halves of the eight bit words constituting each complete sta tion identification data signal, while the other two

memory units

444 and 446 cooperate by storing different halves of the eight bit words constituting each complete time data signal.

The two least significant bit output terminals 484a and 484b of the address counter 486 are also con nected to a fourth bit decode counter 492 which produces a stop pulse for application to a SYNCH circuit 494 each time the address counter 486 has been stepped through four address changes. Signals from the clock 470 are also applied to the SYNCH circuit 494 and are used to control the clock gate 490.

The station input transducer 452 is provided with output terminals 450a and 450j connected to a start AND gate 496. Outputs from this gate are also applied through the SYNCH circuit 494 to the clock gate 490. A Recorded indicator light 498 is connected to the output of the SYNCH circuit 494 to record the insertion of data from the station input transducer 454 and the time counter 474 into their

respective memory units

440, 442, 444 and 446. A pulse generator 500 is provided at the station input transducer to produce the signals applied to the AND gate 496. A delay circuit 502 is connected to the output of the clock gate 490; and this circuit serves to close the AND gate 496 for a duration at least as long as necessary to complete a station check. This serves to prevent anomolous readings from transients or other extraneous effects which might cause different signals to be applied through the station input transducer 454 while a station reading is being taken.

The output of the clock gate 490 is also applied to a WRITE PULSE" circuit 504 which in turn is connected to a write input terminal 509 of each of the

memory units

440, 442, 444 and 446.

In operation of the above described system a reset pulse is applied to a reset terminal 508 of the time counter 474 to clear that counter at the start of a watchmans tour. As the watchman proceeds along his tour, the clock produces a continuous series of accurately time pulses, and these pulses, as divided down by the COUNT DOWN circuit 472 are accumulated in the time counter 474. The pattern of energization of the time counter output terminals 476a 476k, which corresponds to elapsed time, is applied to the third and fourth bit

select units

478 and 480.

When the watchman connects his unit to the first station to be checked, a pulse is generated by the pulse generator 500 and the station input transducer 452 is caused to energize its station identification terminals 45Gb 4501' in accordance with a binary digital code representative of the station identity. This code is applied to the terminals of the first and second bit

select units

454 and 456.

The station input transducer also produces a signal via the AND gate 496 to a START terminal of the SYNCH circuit 494. This allows the next subsequent clock signal to pass through the SYNCH circuit and open the clock gate 490. The following clock signals then pass through the clock gate and step the address counter 486 along so that it successively addresses diffcrent storage locations in the four

memory units

440, 442, 444 and 446. At the same time. and in synchronism with this address stepping, the signals from the least significant digit outputs 484a and 484!) of the ad dress counter 486 are applied to the four bit

select units

454, 456, 478 and 480 causing them successively to transmit the signals present on each of their four inputs to different locations within the associated

memory units

440, 442, 444 and 446.

When four clock pulses have occured, the bit select units will have scanned each of their four inputs. Also at this time. the fourth bit decode counter 492 will produce a signal at the STOP terminal of the SYNCH circuit 494 so that no further stepping of either the address counter or the bit select units will take place. During the stepping of these units, the clock pulses which pass through the clock gate 490 also activate the WRITE PULSE circuit 504. This circuit supplies pulses to write input terminals 509 at each of the

memory units

440, 442. 444 and 446 to allow those units to accept information present on their respective

data input terminals

466, 468, 481 and 482, and to store that data in locations corresponding to the signal pattern at their address terminals 448a 448k.

it will be appreciated from the foregoing that it is possible with the system described herein to store correlated time and station identification data. each having eight bit word lengths, into 256 bit memory units in such a manner that the memory units are used in a most efficient manner for maximum data storage capacity.

Information may be read out of the memory units when the watchmans unit is connected to a computer terminal board as in the case of the preceeding embodiments. In such case address interrogation signals are applied from the computer terminal board to address interrogation terminals 510a 5l0h connected, respectively, to each of the memory unit address terminals. Write signals are also applied from the computer terminal board through a write input terminal 512 to the write input terminals 509 of the memory unit. Data outputs from the memory units is supplied via station identification and time

data output terminals

514, 515, S16 and 517 respectively.

Having thus described the invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which the invention pertains. after understanding the invention, that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the claims appended hereto.

What is claimed and desired to be secured by letters patent is:

l. A watchmans unit for recording the checking of stations by a watchman, said unit comprising.

memory means having a plurality of locations therein for storing signals applied thereto,

clock means for generating time signals corresponding to elapsed time following an applied reset signal, station detector means for producing station signals corresponding to the identity ofa station upon connection of the unit to a station being checked, and

address means operative in response to the production of station signals to direct the time signals being generated to a particular location in said memory means,

16 whereby each location in said memory means which receives a time signal corresponds to the particular station which was being checked during the occurence of said time signal.

2. A watchmans unit according to claim I wherein said memory is a digital bit storage device and wherein said clock means is operative to produce said time signals in binary coded digital form.

3. A watchmans unit according to claim 1 wherein said station detector means is operative to produce said station signals in binary coded digital form.

4. A watchmans unit according to claim 1 wherein said clock means comprises,

an oscillator for producing a continuous series of pulses, binary counter means connected to the output of the oscillator for dividing down the number of pulses and a multiple stage binary register having outputs at each stage, the condition of said outputs corresponding to a binary coded digital representation of said elapsed time.

5. A watchmans unit according to claim 1 wherein said unit includes data entry means comprising means for generating a write pulse duration at a predetermined time following connection of said unit to a check station and means for applying said pulse to a write input terminal of said memory means.

6. A watchmans unit according to claim 5 wherein said means for generating a write pulse comprises first and second monostable multivibrators, said first monostable multivibrator being connected to be actuated upon connection of said watchmans unit to a check station and said second monostable multivibrator being connected to be energized by the resetting of said first monostable multivibrator and means applying the output of said second monostable multivibrator to said write input terminal.

7. A watchmans unit according to claim 6 wherein said unit includes a third monostable multivibrator connected to be ac tuated by said resetting of said first monostable multivibrator and an indicator connected to be actuated by said third monostable multivibrator.

8. A watchmans unit according to claim 7 wherein said first monostable multivibrator is connected to be held in reset condition by said third monostable multivibrator.

9. A watchmans unit according to claim 1 wherein said address means is operative to direct said time signals being generated to locations in said memory means which correspond to the station signals.

10. A watchmans unit according to claim 9 wherein said clock means includes a multistage binary register a means for setting the various stages of said register in accordance with a binary code representative of elapsed time,

and wherein said memory means includes a plurality of memory units, each having several binary code bit memory locations therein, each binary register stage being connected to a different one of said memory units. 11. A watchmans unit according to claim 9 wherein said address means comprises means for directing the outputs from said binary register stages to corresponding memory locations in said memory units in accordance with a station identification code.

12. A watchmans unit according to claim 9 wherein said memory is a digital bit storage device having at each of several bit locations a bit memory capable, when activated. of retaining bit information supplied thereto and wherein said address means comprises decoding means for activating different ones of said bit storage devices according to said station signals.

13. A watchmans unit according to claim 9 wherein said station detector means comprises a plurality of terminals and means for producing digital signals on various ones of said terminals in accordance with a binary digital representation of the identity of a station.

14. A watchmans unit according to claim 10 wherein the memory comprises a plurality of memory units corresponding in number to the number of stages of said binary register. each unit being connected to receive the binary output of a different one of said stages.

and wherein said address means is operative to direct the binary outputs produced at a given time to corresponding locations in said memory units.

15. A watchmans unit according to claim 9 wherein each memory unit is a digital bit storage device having at each of several bit locations a bit memory capable, when activated, of retaining bit information supplied thereto.

16. A watchmans unit according to claim I wherein said memory means further includes a second plurality of locations therein for storing station signals, each of said second plurality of locations corresponding to a different one of the first mentioned plurality of locations,

and wherein said address means is operative in response to the production of station signals to direct the station signals and the simultaneously produced time signals to corresponding ones of said second and first plurality of locations.

17. A watchmans unit according to claim 16 wherein said memory is a digital bit storage device and wherein said clock means is operative to produce said time signals in binary coded digital form.

18. A watchmans unit according to claim 16 wherein said station detector means is operative to produce said station signals in binary coded digital form.

19. A watchmans unit according to claim 16 wherein said clock means comprises an oscillator means for producing a continuous series of pulses.

and a multiple stage binary register for receiving and accumulating said pulse and having plural outputs whose pattern of energization corresponds to the accumulated number of pulses therein.

20. A watchmans unit for recording the checking of stations by a watchman. said unit comprising,

memory means having a plurality of data input terminals for receiving digitally coded data and a plurality of address terminals for directing received data to different locations therein corresponding to received address signals,

time signal data producing means comprising pulse generator means for producing a continuous suc- 18 cession of pulses and multiple stage digital register for accumulating said pulses and attaining different states in its various stages corresponding to the number of accumulated pulses.

means connecting the various stages of said register to said data input terminals of said memory means.

station signal identification means for producing digi tally coded station identification signals corresponding to a station key when applied thereto.

and means directing said station identification signals to said address terminals of said memory means.

21. A watchmans unit according to claim 20 wherein said memory means has a plurality of data output terminals for connection to a terminal board and a plurality of address interrogation terminals for connection to a terminal board,

said data output terminals and said address interrogation terminals being connected to said memory means in a manner such that interrogation signals applied in various patterns to said address intcrr0- gation terminals will cause said data output terminals to produce signals representative of the data in the memory locations corresponding to said patterns.

22. A watchmans unit for recording the checking of stations by a watchman, said unit comprising memory means having a first plurality of data input terminals for receiving digitally coded time data and a second plurality of data input terminals for receiving digitally coded station identification data,

time signal data producing means comprising pulse generator means for producing a continuous succession of pulses and a multiple stage digital register for accumulating said pulse and energizing a plurality of time data terminals according to patterns representative of the number of accumulated pulses. said time data terminals being connected to corresponding ones of said first plurality of data input terminals,

station signal identification means for producing digitally coded station identification signals at a plurality of station identification terminals with the pattern of said signals corresponding to the identity of a station key applied to said unit said station identification terminals connected to corresponding ones of said second plurality of data input terminals,

a common address means comprising a register having a plurality of output terminals, said register being responsive to the application of a station key to said watchmans unit to change the pattern of energization of its output terminals according to a predetermined sequence,

said output terminals each being connected to corresponding address terminals of said memory means,

said memory means being responsive to the application of address signals to said address terminals to direct data at said first and second data input terminals to corresponding locations therein.

23. A watchmans unit according to claim 22 wherein said memory means comprises a first signal storage unit having said first plurality of data input terminals and a first set of address terminals and a second signal storage unit having said second plurality of data input terminals and a second set of address terminals.

clock means in said watchman s unit for generating in digital code format time data signals representative of elapsed time from a given point in time,

correlation means and memory means in said watchman's unit to record therein, in correlated arrangement, the digitally coded station identification and time data signals produced when said unit is connected to one of said station connectors and computer terminal means operative when connected to a watchmans unit. to read out the signals stored therein.

PATENT NO.

DATED INVYENTOR(S) UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 35 After the words "of the", delete [terminal] Column 9, line 6 After the word "output", delete [terminals] and in its place insert terminal.

Column 13, line 36 After the word "bit" delete [selection] and in its place insert select.

Column 14, lines 25 G 27 The word "SYNCH" should be set off in quotation marks.

Column 14, lines 66, 67 f 68 e The words "START" and "SYNCH" should be set off in quotation marls.

Column 15, lines 15 G 20 The words "STOP", "SYNCH" and "WRITE PULSE" should be set off in quotation marks.

Column 16, line 59 Delete the "a" appearing at the beginning of the line and insert "and".

Column 18, line 1 After the word "and", insert "a".

Column 18, line 36 Delete the word [pulse] and insert in its place pulses.

Signed and Scaled this first Day of mum [SEAL] and in its place insert second.

Arrest:

RUTH C. MASON Alluring ()ffirer

Claims

1. A watchman''s unit for recording the checking of stations by a watchman, said unit comprising, memory means having a plurality of locations therein for storing signals applied thereto, clock means for generating time signals corresponding to elapsed time following an applied reset signal, station detector means for producing station signals corresponding to the identity of a station upon connection of the unit to a station being checked, and address means operative in response to the production of station signals to direct the time signals being generated to a particular location in said memory means, whereby each location in said memory means which receives a time signal corresponds to the particular station which was being checked during the occurence of said time signal.

2. A watchman''s unit according to claim 1 wherein said memory is a digital bit storage device and wherein said clock means is operative to produce said time signals in binary coded digital form.

3. A watchman''s unit according to claim 1 wherein said station detector means is operative to produce said station signals in binary coded digital form.

4. A watchman''s unit according to claim 1 wherein said clock means comprises, an oscillator for producing a continuous series of pulses, binary counter means connected to the output of the oscillator for dividing down The number of pulses and a multiple stage binary register having outputs at each stage, the condition of said outputs corresponding to a binary coded digital representation of said elapsed time.

5. A watchman''s unit according to claim 1 wherein said unit includes data entry means comprising means for generating a write pulse duration at a predetermined time following connection of said unit to a check station and means for applying said pulse to a write input terminal of said memory means.

6. A watchman''s unit according to claim 5 wherein said means for generating a write pulse comprises first and second monostable multivibrators, said first monostable multivibrator being connected to be actuated upon connection of said watchman''s unit to a check station and said second monostable multivibrator being connected to be energized by the resetting of said first monostable multivibrator and means applying the output of said second monostable multivibrator to said write input terminal.

7. A watchman''s unit according to claim 6 wherein said unit includes a third monostable multivibrator connected to be actuated by said resetting of said first monostable multivibrator and an indicator connected to be actuated by said third monostable multivibrator.

8. A watchman''s unit according to claim 7 wherein said first monostable multivibrator is connected to be held in reset condition by said third monostable multivibrator.

9. A watchman''s unit according to claim 1 wherein said address means is operative to direct said time signals being generated to locations in said memory means which correspond to the station signals.

10. A watchman''s unit according to claim 9 wherein said clock means includes a multistage binary register a means for setting the various stages of said register in accordance with a binary code representative of elapsed time, and wherein said memory means includes a plurality of memory units, each having several binary code bit memory locations therein, each binary register stage being connected to a different one of said memory units.

11. A watchman''s unit according to claim 9 wherein said address means comprises means for directing the outputs from said binary register stages to corresponding memory locations in said memory units in accordance with a station identification code.

12. A watchman''s unit according to claim 9 wherein said memory is a digital bit storage device having at each of several bit locations a bit memory capable, when activated, of retaining bit information supplied thereto and wherein said address means comprises decoding means for activating different ones of said bit storage devices according to said station signals.

13. A watchman''s unit according to claim 9 wherein said station detector means comprises a plurality of terminals and means for producing digital signals on various ones of said terminals in accordance with a binary digital representation of the identity of a station.

14. A watchman''s unit according to claim 10 wherein the memory comprises a plurality of memory units corresponding in number to the number of stages of said binary register, each unit being connected to receive the binary output of a different one of said stages, and wherein said address means is operative to direct the binary outputs produced at a given time to corresponding locations in said memory units.

15. A watchman''s unit according to claim 9 wherein each memory unit is a digital bit storage device having at each of several bit locations a bit memory capable, when activated, of retaining bit information supplied thereto.

16. A watchman''s unit according to claim 1 wherein said memory means further includes a second plurality of locations therein for storing station signals, each of said second plurality of locations corresponding to a different one of the first mentioned plurality of locations, and wherein said address Means is operative in response to the production of station signals to direct the station signals and the simultaneously produced time signals to corresponding ones of said second and first plurality of locations.

17. A watchman''s unit according to claim 16 wherein said memory is a digital bit storage device and wherein said clock means is operative to produce said time signals in binary coded digital form.

18. A watchman''s unit according to claim 16 wherein said station detector means is operative to produce said station signals in binary coded digital form.

19. A watchman''s unit according to claim 16 wherein said clock means comprises an oscillator means for producing a continuous series of pulses, and a multiple stage binary register for receiving and accumulating said pulse and having plural outputs whose pattern of energization corresponds to the accumulated number of pulses therein.

20. A watchman''s unit for recording the checking of stations by a watchman, said unit comprising, memory means having a plurality of data input terminals for receiving digitally coded data and a plurality of address terminals for directing received data to different locations therein corresponding to received address signals, time signal data producing means comprising pulse generator means for producing a continuous succession of pulses and multiple stage digital register for accumulating said pulses and attaining different states in its various stages corresponding to the number of accumulated pulses, means connecting the various stages of said register to said data input terminals of said memory means, station signal identification means for producing digitally coded station identification signals corresponding to a station key when applied thereto, and means directing said station identification signals to said address terminals of said memory means.

21. A watchman''s unit according to claim 20 wherein said memory means has a plurality of data output terminals for connection to a terminal board and a plurality of address interrogation terminals for connection to a terminal board, said data output terminals and said address interrogation terminals being connected to said memory means in a manner such that interrogation signals applied in various patterns to said address interrogation terminals will cause said data output terminals to produce signals representative of the data in the memory locations corresponding to said patterns.

22. A watchman''s unit for recording the checking of stations by a watchman, said unit comprising memory means having a first plurality of data input terminals for receiving digitally coded time data and a second plurality of data input terminals for receiving digitally coded station identification data, time signal data producing means comprising pulse generator means for producing a continuous succession of pulses and a multiple stage digital register for accumulating said pulse and energizing a plurality of time data terminals according to patterns representative of the number of accumulated pulses, said time data terminals being connected to corresponding ones of said first plurality of data input terminals, station signal identification means for producing digitally coded station identification signals at a plurality of station identification terminals with the pattern of said signals corresponding to the identity of a station key applied to said unit said station identification terminals connected to corresponding ones of said second plurality of data input terminals, a common address means comprising a register having a plurality of output terminals, said register being responsive to the application of a station key to said watchman''s unit to change the pattern of energization of its output terminals according to a predetermined sequence, said output terminals each being connected to corresponding address terminals of said memory means, SAID memory means being responsive to the application of address signals to said address terminals to direct data at said first and second data input terminals to corresponding locations therein.

23. A watchman''s unit according to claim 22 wherein said memory means comprises a first signal storage unit having said first plurality of data input terminals and a first set of address terminals and a second signal storage unit having said second plurality of data input terminals and a second set of address terminals. and wherein said common address means output terminals are connected to corresponding ones of both said first and second sets of address terminals.

24. A security system comprising a plurality of station connectors distributed about a premises to be checked, at least one watchman''s unit, station identification signal producing means in said unit and operative to generate, in digital code format, station identification signals corresponding to the identification of different ones of said stations upon connection of said unit to said stations, clock means in said watchman''s unit for generating in digital code format time data signals representative of elapsed time from a given point in time, correlation means and memory means in said watchman''s unit to record therein, in correlated arrangement, the digitally coded station identification and time data signals produced when said unit is connected to one of said station connectors, and computer terminal means operative when connected to a watchman''s unit, to read out the signals stored therein.