This module provides various time-related functions. For relatedfunctionality, see also the datetime and calendar modules.

1. Time Clock 104
2. Time Clock 1:00 Pm
3. Time Clock 10 Minutes

Although this module is always available,not all functions are available on all platforms. Most of the functionsdefined in this module call platform C library functions with the same name. Itmay sometimes be helpful to consult the platform documentation, because thesemantics of these functions varies among platforms.

An explanation of some terminology and conventions is in order.

Time.is displays exact, official atomic clock time for any time zone (more than 7 million locations) in 52 languages. Automated access is prohibited. Support for cookies and JavaScript is required. UPunch Starter Time Clock Bundle with 100-Cards, 1 Time Card Rack, 1 Ribbon & 2 Keys (HN1500) 4.3 out of 5 stars 1,084. Get it as soon as Thu, Dec 10.

• The epoch is the point where the time starts, and is platformdependent. For Unix, the epoch is January 1, 1970, 00:00:00 (UTC).To find out what the epoch is on a given platform, look attime.gmtime(0).

• The term seconds since the epoch refers to the total numberof elapsed seconds since the epoch, typically excludingleap seconds. Leap seconds are excluded from this total on allPOSIX-compliant platforms.

• The functions in this module may not handle dates and times before the epoch orfar in the future. The cut-off point in the future is determined by the Clibrary; for 32-bit systems, it is typically in 2038.

• Function strptime() can parse 2-digit years when given %y formatcode. When 2-digit years are parsed, they are converted according to the POSIXand ISO C standards: values 69–99 are mapped to 1969–1999, and values 0–68are mapped to 2000–2068.

• UTC is Coordinated Universal Time (formerly known as Greenwich Mean Time, orGMT). The acronym UTC is not a mistake but a compromise between English andFrench.

• DST is Daylight Saving Time, an adjustment of the timezone by (usually) onehour during part of the year. DST rules are magic (determined by local law) andcan change from year to year. The C library has a table containing the localrules (often it is read from a system file for flexibility) and is the onlysource of True Wisdom in this respect.

• The precision of the various real-time functions may be less than suggested bythe units in which their value or argument is expressed. E.g. on most Unixsystems, the clock “ticks” only 50 or 100 times a second.

• On the other hand, the precision of time() and sleep() is betterthan their Unix equivalents: times are expressed as floating point numbers,time() returns the most accurate time available (using Unixgettimeofday() where available), and sleep() will accept a timewith a nonzero fraction (Unix select() is used to implement this, whereavailable).

• The time value as returned by gmtime(), localtime(), andstrptime(), and accepted by asctime(), mktime() andstrftime(), is a sequence of 9 integers. The return values ofgmtime(), localtime(), and strptime() also offer attributenames for individual fields.

  See struct_time for a description of these objects.

  Changed in version 3.3: The struct_time type was extended to provide the tm_gmtoffand tm_zone attributes when platform supports correspondingstructtm members.

  Changed in version 3.6: The struct_time attributes tm_gmtoff and tm_zoneare now available on all platforms.

• Use the following functions to convert between time representations:

  From	To	Use
  seconds since the epoch	struct_time inUTC
  seconds since the epoch	struct_time inlocal time
  struct_time inUTC	seconds since the epoch
  struct_time inlocal time	seconds since the epoch

Functions¶

Convert a tuple or struct_time representing a time as returned bygmtime() or localtime() to a string of the followingform: 'SunJun2023:21:051993'. The day field is two characters longand is space padded if the day is a single digit,e.g.: 'WedJun904:26:401993'.

If t is not provided, the current time as returned by localtime()is used. Locale information is not used by asctime().

Note

Unlike the C function of the same name, asctime() does not add atrailing newline.

Return the clk_id of the thread-specific CPU-time clock for the specified thread_id.

Use threading.get_ident() or the identattribute of threading.Thread objects to get a suitable valuefor thread_id.

Warning

Passing an invalid or expired thread_id may result inundefined behavior, such as segmentation fault.

Availability: Unix (see the man page for pthread_getcpuclockid(3) forfurther information).

Return the resolution (precision) of the specified clock clk_id. Refer toClock ID Constants for a list of accepted values for clk_id.

Availability: Unix.

New in version 3.3.

Return the time of the specified clock clk_id. Refer toClock ID Constants for a list of accepted values for clk_id.

Availability: Unix.

Similar to clock_gettime() but return time as nanoseconds.

Availability: Unix.

New in version 3.7.

Set the time of the specified clock clk_id. Currently,CLOCK_REALTIME is the only accepted value for clk_id.

Availability: Unix.

Similar to clock_settime() but set time with nanoseconds.

Availability: Unix.

New in version 3.7.

Convert a time expressed in seconds since the epoch to a string of a form:'SunJun2023:21:051993' representing local time. The day fieldis two characters long and is space padded if the day is a single digit,e.g.: 'WedJun904:26:401993'.

If secs is not provided or None, the current time asreturned by time() is used. ctime(secs) is equivalent toasctime(localtime(secs)). Locale information is not used byctime().

Get information on the specified clock as a namespace object.Supported clock names and the corresponding functions to read their valueare:

• 'monotonic': time.monotonic()

• 'perf_counter': time.perf_counter()

• 'process_time': time.process_time()

• 'thread_time': time.thread_time()

• 'time': time.time()

The result has the following attributes:

• adjustable: True if the clock can be changed automatically (e.g. bya NTP daemon) or manually by the system administrator, False otherwise

• implementation: The name of the underlying C function used to getthe clock value. Refer to Clock ID Constants for possible values.

• monotonic: True if the clock cannot go backward,False otherwise

• resolution: The resolution of the clock in seconds (float)

Convert a time expressed in seconds since the epoch to a struct_time inUTC in which the dst flag is always zero. If secs is not provided orNone, the current time as returned by time() is used. Fractionsof a second are ignored. See above for a description of thestruct_time object. See calendar.timegm() for the inverse of thisfunction.

Like gmtime() but converts to local time. If secs is not provided orNone, the current time as returned by time() is used. The dstflag is set to 1 when DST applies to the given time.

This is the inverse function of localtime(). Its argument is thestruct_time or full 9-tuple (since the dst flag is needed; use -1as the dst flag if it is unknown) which expresses the time in local time, notUTC. It returns a floating point number, for compatibility with time().If the input value cannot be represented as a valid time, eitherOverflowError or ValueError will be raised (which depends onwhether the invalid value is caught by Python or the underlying C libraries).The earliest date for which it can generate a time is platform-dependent.

Return the value (in fractional seconds) of a monotonic clock, i.e. a clockthat cannot go backwards. The clock is not affected by system clock updates.The reference point of the returned value is undefined, so that only thedifference between the results of consecutive calls is valid.

New in version 3.3.

Changed in version 3.5: The function is now always available and always system-wide.

Similar to monotonic(), but return time as nanoseconds.

Return the value (in fractional seconds) of a performance counter, i.e. aclock with the highest available resolution to measure a short duration. Itdoes include time elapsed during sleep and is system-wide. The referencepoint of the returned value is undefined, so that only the difference betweenthe results of consecutive calls is valid.

New in version 3.3.

Similar to perf_counter(), but return time as nanoseconds.

Return the value (in fractional seconds) of the sum of the system and userCPU time of the current process. It does not include time elapsed duringsleep. It is process-wide by definition. The reference point of thereturned value is undefined, so that only the difference between the resultsof consecutive calls is valid.

New in version 3.3.

Similar to process_time() but return time as nanoseconds.

Suspend execution of the calling thread for the given number of seconds.The argument may be a floating point number to indicate a more precise sleeptime. The actual suspension time may be less than that requested because anycaught signal will terminate the sleep() following execution of thatsignal’s catching routine. Also, the suspension time may be longer thanrequested by an arbitrary amount because of the scheduling of other activityin the system.

Changed in version 3.5: The function now sleeps at least secs even if the sleep is interruptedby a signal, except if the signal handler raises an exception (seePEP 475 for the rationale).

Convert a tuple or struct_time representing a time as returned bygmtime() or localtime() to a string as specified by the formatargument. If t is not provided, the current time as returned bylocaltime() is used. format must be a string. ValueError israised if any field in t is outside of the allowed range.

0 is a legal argument for any position in the time tuple; if it is normallyillegal the value is forced to a correct one.

The following directives can be embedded in the format string. They are shownwithout the optional field width and precision specification, and are replacedby the indicated characters in the strftime() result:

Notes:

1. When used with the strptime() function, the %p directive only affectsthe output hour field if the %I directive is used to parse the hour.

2. The range really is 0 to 61; value 60 is valid intimestamps representing leap seconds and value 61 is supportedfor historical reasons.

3. When used with the strptime() function, %U and %W are only used incalculations when the day of the week and the year are specified.

Here is an example, a format for dates compatible with that specified in theRFC 2822 Internet email standard. 1

Additional directives may be supported on certain platforms, but only theones listed here have a meaning standardized by ANSI C. To see the full setof format codes supported on your platform, consult the strftime(3)documentation.

On some platforms, an optional field width and precision specification canimmediately follow the initial '%' of a directive in the following order;this is also not portable. The field width is normally 2 except for %j whereit is 3.

Parse a string representing a time according to a format. The return valueis a struct_time as returned by gmtime() orlocaltime().

The format parameter uses the same directives as those used bystrftime(); it defaults to '%a%b%d%H:%M:%S%Y' which matches theformatting returned by ctime(). If string cannot be parsed accordingto format, or if it has excess data after parsing, ValueError israised. The default values used to fill in any missing data when moreaccurate values cannot be inferred are (1900,1,1,0,0,0,0,1,-1).Both string and format must be strings.

For example:

Support for the %Z directive is based on the values contained in tznameand whether daylight is true. Because of this, it is platform-specificexcept for recognizing UTC and GMT which are always known (and are considered tobe non-daylight savings timezones).

Only the directives specified in the documentation are supported. Becausestrftime() is implemented per platform it can sometimes offer moredirectives than those listed. But strptime() is independent of any platformand thus does not necessarily support all directives available that are notdocumented as supported.

The type of the time value sequence returned by gmtime(),localtime(), and strptime(). It is an object with a namedtuple interface: values can be accessed by index and by attribute name. Thefollowing values are present:

Note that unlike the C structure, the month value is a range of [1, 12], not[0, 11].

In calls to mktime(), tm_isdst may be set to 1 when daylightsavings time is in effect, and 0 when it is not. A value of -1 indicates thatthis is not known, and will usually result in the correct state being filled in.

When a tuple with an incorrect length is passed to a function expecting astruct_time, or having elements of the wrong type, aTypeError is raised.

Return the time in seconds since the epoch as a floating pointnumber. The specific date of the epoch and the handling ofleap seconds is platform dependent.On Windows and most Unix systems, the epoch is January 1, 1970,00:00:00 (UTC) and leap seconds are not counted towards the timein seconds since the epoch. This is commonly referred to asUnix time.To find out what the epoch is on a given platform, look atgmtime(0).

Note that even though the time is always returned as a floating pointnumber, not all systems provide time with a better precision than 1 second.While this function normally returns non-decreasing values, it can return alower value than a previous call if the system clock has been set backbetween the two calls.

The number returned by time() may be converted into a more commontime format (i.e. year, month, day, hour, etc…) in UTC by passing it togmtime() function or in local time by passing it to thelocaltime() function. In both cases astruct_time object is returned, from which the componentsof the calendar date may be accessed as attributes.

Return the value (in fractional seconds) of the sum of the system and userCPU time of the current thread. It does not include time elapsed duringsleep. It is thread-specific by definition. The reference point of thereturned value is undefined, so that only the difference between the resultsof consecutive calls in the same thread is valid.

Availability: Windows, Linux, Unix systems supportingCLOCK_THREAD_CPUTIME_ID.

New in version 3.7.

Similar to thread_time() but return time as nanoseconds.

Similar to time() but returns time as an integer number of nanosecondssince the epoch.

New in version 3.7.

Reset the time conversion rules used by the library routines. The environmentvariable TZ specifies how this is done. It will also set the variablestzname (from the TZ environment variable), timezone (non-DSTseconds West of UTC), altzone (DST seconds west of UTC) and daylight(to 0 if this timezone does not have any daylight saving time rules, or tononzero if there is a time, past, present or future when daylight saving timeapplies).

Availability: Unix.

Note

Although in many cases, changing the TZ environment variable mayaffect the output of functions like localtime() without callingtzset(), this behavior should not be relied on.

The TZ environment variable should contain no whitespace.

The standard format of the TZ environment variable is (whitespaceadded for clarity):

Where the components are:

Three or more alphanumerics giving the timezone abbreviations. These will bepropagated into time.tzname

The offset has the form: ±hh[:mm[:ss]]. This indicates the valueadded the local time to arrive at UTC. If preceded by a ‘-‘, the timezoneis east of the Prime Meridian; otherwise, it is west. If no offset followsdst, summer time is assumed to be one hour ahead of standard time.

Indicates when to change to and back from DST. The format of thestart and end dates are one of the following:

The Julian day n (1 <= n <= 365). Leap days are not counted, so inall years February 28 is day 59 and March 1 is day 60.

The zero-based Julian day (0 <= n <= 365). Leap days are counted, andit is possible to refer to February 29.

The d’th day (0 <= d <= 6) of week n of month m of the year (1<= n <= 5, 1 <= m <= 12, where week 5 means “the last d day inmonth m” which may occur in either the fourth or the fifthweek). Week 1 is the first week in which the d’th day occurs. Dayzero is a Sunday.

time has the same format as offset except that no leading sign(‘-‘ or ‘+’) is allowed. The default, if time is not given, is 02:00:00.

On many Unix systems (including *BSD, Linux, Solaris, and Darwin), it is moreconvenient to use the system’s zoneinfo (tzfile(5)) database tospecify the timezone rules. To do this, set the TZ environmentvariable to the path of the required timezone datafile, relative to the root ofthe systems ‘zoneinfo’ timezone database, usually located at/usr/share/zoneinfo. For example, 'US/Eastern','Australia/Melbourne', 'Egypt' or 'Europe/Amsterdam'.

Clock ID Constants¶

These constants are used as parameters for clock_getres() andclock_gettime().

Identical to CLOCK_MONOTONIC, except it also includes any time thatthe system is suspended.

This allows applications to get a suspend-aware monotonic clock withouthaving to deal with the complications of CLOCK_REALTIME, which mayhave discontinuities if the time is changed using settimeofday() orsimilar.

Availability: Linux 2.6.39 or later.

The Solaris OS has a CLOCK_HIGHRES timer that attempts to use an optimalhardware source, and may give close to nanosecond resolution.CLOCK_HIGHRES is the nonadjustable, high-resolution clock.

Availability: Solaris.

New in version 3.3.

Clock that cannot be set and represents monotonic time since some unspecifiedstarting point.

Availability: Unix.

Similar to CLOCK_MONOTONIC, but provides access to a rawhardware-based time that is not subject to NTP adjustments.

Availability: Linux 2.6.28 and newer, macOS 10.12 and newer.

New in version 3.3.

High-resolution per-process timer from the CPU.

Availability: Unix.

High-resolution per-process timer from the CPU.

Availability: FreeBSD, NetBSD 7 or later, OpenBSD.

New in version 3.7.

The system must have a current leap second table in order for this to givethe correct answer. PTP or NTP software can maintain a leap second table.

Availability: Linux.

Thread-specific CPU-time clock.

Availability: Unix.

New in version 3.3.

Time whose absolute value is the time the system has been running and notsuspended, providing accurate uptime measurement, both absolute andinterval.

Availability: FreeBSD, OpenBSD 5.5 or later.

Clock that increments monotonically, tracking the time since an arbitrarypoint, unaffected by frequency or time adjustments and not incremented whilethe system is asleep.

Availability: macOS 10.12 and newer.

New in version 3.8.

The following constant is the only parameter that can be sent toclock_settime().

System-wide real-time clock. Setting this clock requires appropriateprivileges.

Availability: Unix.

Timezone Constants¶

The offset of the local DST timezone, in seconds west of UTC, if one is defined.This is negative if the local DST timezone is east of UTC (as in Western Europe,including the UK). Only use this if daylight is nonzero. See note below.

Nonzero if a DST timezone is defined. See note below.

The offset of the local (non-DST) timezone, in seconds west of UTC (negative inmost of Western Europe, positive in the US, zero in the UK). See note below.

A tuple of two strings: the first is the name of the local non-DST timezone, thesecond is the name of the local DST timezone. If no DST timezone is defined,the second string should not be used. See note below.

Note

For the above Timezone constants (altzone, daylight, timezone,and tzname), the value is determined by the timezone rules in effectat module load time or the last time tzset() is called and may be incorrectfor times in the past. It is recommended to use the tm_gmtoff andtm_zone results from localtime() to obtain timezone information.

See also

More object-oriented interface to dates and times.

Internationalization services. The locale setting affects the interpretationof many format specifiers in strftime() and strptime().

General calendar-related functions. timegm() is theinverse of gmtime() from this module.

Footnotes

The use of %Z is now deprecated, but the %z escape that expands to thepreferred hour/minute offset is not supported by all ANSI C libraries. Also, astrict reading of the original 1982 RFC 822 standard calls for a two-digityear (%y rather than %Y), but practice moved to 4-digit years long before theyear 2000. After that, RFC 822 became obsolete and the 4-digit year hasbeen first recommended by RFC 1123 and then mandated by RFC 2822.

A time clock, sometimes known as a clock card machine or punch clock or time recorder, is a device that records start and end times for hourly employees (or those on flexi-time) at a place of business.

In mechanical time clocks, this was accomplished by inserting a heavy paper card, called a time card, into a slot on the time clock. When the time card hit a contact at the rear of the slot, the machine would print day and time information (a timestamp) on the card. One or more time cards could serve as a timesheet or provide the data to fill one. This allowed a timekeeper to have an official record of the hours an employee worked to calculate the pay owed an employee.

The terms Bundy clock, bundy clock, or just bundy^[1] have been used in Australian English for time clocks. The term comes from brothers Willard and Harlow Bundy.

History[edit]

Origins[edit]

An early and influential time clock, sometimes described as the first, was invented on November 20, 1888, by Willard Le Grand Bundy,^[2] a jeweler in Auburn, New York. His patent of 1890^[3] speaks of mechanical time recorders for workers in terms that suggest that earlier recorders already existed, but Bundy's had various improvements; for example, each worker had his own key. A year later his brother, Harlow Bundy, organized the Bundy Manufacturing Company,^[4][5] and began mass-producing time clocks.

In 1900, the time recording business of Bundy Manufacturing, along with two other time equipment businesses, was consolidated into the International Time Recording Company (ITR).^[6][7][8][9]

In 1911, ITR, Bundy Mfg., and two other companies were amalgamated (via stock acquisition), forming a fifth company, Computing-Tabulating-Recording Company (CTR), which would later change its name to IBM.^[10]

The Bundy clock (see image left) was used by Birmingham City Transport to ensure that bus drivers did not depart from outlying termini before the due time; now preserved at Walsall Arboretum.

In 1909, Halbert P. Gillette explained about the state of the art around time clocks in those days:

Time clocks.—Such an appliance which may not, in general, be used in the field, but which is of immense value in the office and particularly in a shop, is the time clock. Various forms of time clocks are in common use, two types of which are illustrated. [The first] is a time card recorder, which is a clock so made that it will automatically stamp on a card inserted in a slot in the clock by the workman the time of his arrival and of his departure. The cards are made to hold a record covering the pay period and need no attention from a timekeeper or clerk until the termination of this period. The record of the men's time can then be compiled very readily by one who need not be a skilled mathematician or time clerk.

The time clock system has been developed very highly in shops for keeping track of time used in completing any job by workmen, but as this in a way is not in the realm of field cost keeping, it will not be entered into here.

Another form of time clock [...] has the numbers of the employees fixed on the outer edge of a disk or ring and a record is made by the employee who shifts a revolving arm and punches his number upon entering the office and leaving. The working up of employees' time then becomes simply a matter of computation from printed figures. These two types are made by the International Time Recording Co. of New York.^[11]

An example of this other form of time clock, made by IBM, is pictured. The face shows employee numbers which would be dialed up by employees entering and leaving the factory. The day and time of entry and exit was punched onto cards inside the box.^[12]

Mid 20th century[edit]

In 1958, IBM's Time Equipment Division was sold to the Simplex Time Recorder Company. However, in the United Kingdom ITR (a subsidiary of IBM United Kingdom Ltd.) was the subject of a management buy-out in 1963 and reverted to International Time Recorders. In 1982, International Time Recorders was acquired by Blick Industries of Swindon, England, who were themselves later absorbed by Stanley Security Systems.

The first punched-card system to be linked to a Z80 microprocessor was developed by Kronos Incorporated in the late 1970s and introduced as a product in 1979.^[13]

Late 20th century[edit]

Time Clock 104

In the late 20th century, time clocks started to move away from the mechanical machines to computer-based, electronic time and attendance systems. The employee registers with the system by swiping a magnetic stripe card, scanning a barcode, bringing an RFID (radio-frequency identification) tag close to a reader, entering a number or using a biometric reader. These systems are much more advanced than the mechanical time clock: various reports can be generated, including on compliance with the European Working Time Directive, and a Bradford factor report. Employees can also use the system to request holidays, enter absence requests and view their worked hours. User interfaces can be personalized and offer robust self-service capabilities.

Electronic time clock machines are manufactured in many designs by companies in China and sold under various brand names in places around the world, with accompanying software to extract the data from a single time clock machine, or several machines, and process the data into reports. In most cases local suppliers offer technical support and in some cases installation services.

More recently, time clocks have started to adopt technology commonly seen in phones and tablets – called 'Smartclocks'. The 'state of the art' smartclocks come with multi-touch screens, full color displays, real time monitoring for problems, wireless networking and over the air updates. Some of the smartclocks use front-facing cameras to capture employee clock-ins to deter 'buddy clocking' or 'buddy punching', whereby one employee fraudulently records the time of another. This problem usually requires expensive biometric devices. With the increasing popularity of cloud-based software, some of the newer time clocks are built to work seamlessly with the cloud.^[14]

Time Clock 1:00 Pm

Types[edit]

Basic time clock[edit]

A basic time clock will just stamp the date and time on a time card, similar to a parking validation machine. These will usually be activated by a button that a worker must press to stamp their card, or stamp upon full insertion. Some machines use punch hole cards instead of stamping, which can facilitate automated processing on machinery not capable of optical character recognition.

There are also variations based on manufacture and machine used, and whether the user wants to record weekly or monthly recordings. The time cards usually have the workdays, 'time in', and 'time out' areas marked on them so that employees can 'punch in' or 'punch out' in the correct place. The employee may be responsible for lining up the correct area of the card to be punched or stamped. Some time clocks feature a bell or signal relay to alert employees as to a certain time or break.^{[citation needed]}

Fraudulent operation of time clocks can include overstamping, where one time is stamped over another, and buddy-punching, where one employee records time for another. In extreme cases, employees can use buddy-punching to skip entire days of work or accumulate additional overtime.

Self-calculating machines[edit]

Self-calculating machines are similar to basic time clocks. Nevertheless, at the end of each period the total time recorded is added up allowing for quicker processing by human resources or payroll. These machines sometimes have other functions such as automatic stamping, dual-colour printing, and automated column shift.^{[citation needed]}

Software based time and attendance systems are similar to paper-based systems, but they rely on computers and check-in terminals. They are backed up with software that can be integrated with the human resources department and in some cases payroll software. These types of systems are becoming more popular but due to high initial costs they are usually only adopted by large business of over 30 employees. Despite this they can save a business a lot of money every year by cutting down errors and reducing administration time.^{[15][citation needed]}

Mobile time tracking[edit]

With the mass market proliferation of mobile devices (smart phones, handheld devices), new types of self-calculating time tracking systems have been invented which allow a mobile workforce – such as painting companies or construction companies - to track employees 'on' and 'off' hours. This is generally accomplished through either a mobile application, or an IVR based phone call in system. Using a mobile device allows enterprises to better validate that their employees or suppliers are physically 'clocking in' at a specific location using the GPS functionality of a mobile phone for extra validation.

Biometrics[edit]

Biometric time clocks are a feature of more advanced time and attendance systems. Rather than using a key, code or chip to identify the user, they rely on a unique attribute of the user, such as a hand print, finger print, finger vein, palm vein, facial recognition, iris or retina. The user will have their attribute scanned into the system. Biometric readers are often used in conjunction with an access control system, granting the user access to a building, and at the same time clocking them in recording the time and date. These systems also attempt to cut down on fraud such as 'buddy clocking.' When combined with an access control system they can help prevent other types of fraud such as 'ghost employees', where additional identities are added to payroll but don't exist.

See also[edit]

References[edit]

1. ^Bundy. (n.d.). Collins English Dictionary – Complete & Unabridged 10th Edition. Retrieved April 10, 2014, from Dictionary.com website: http://dictionary.reference.com/browse/bundy
2. ^Willard Legrand Bundy Biography
3. ^U.S. Patent 452,894
4. ^IBM Archives: Bundy Manufacturing Co.
5. ^Bundy Museum of History & Art
6. ^Engelbourg (1954) p.33
7. ^Belden, Martin; Belden, Marva (1961). The Life of Thomas J. Watson, Little, Brown; p. 92
8. ^IBM Archives: International Time Recording
9. ^IBM Archives: ITR time recorder
10. ^Bennett, Frank P.; Company (June 17, 1911). United States Investor. 22, Part 2. p. 1298 (26).
11. ^Gillette, Halbert Powers, and Richard T. Dana. Construction Cost Keeping and Management. Gillette Publishing Company, 1909, p. 110-112.
12. ^Engelbourg, Saul (1954). International Business Machines: A Business History (Ph.D.). Columbia University. p. 385. Reprinted by Arno Press, 1976, from the best available copy. Some text is illegible.
13. ^Kronos History
14. ^David Needle, TabTimes, Android tablet gives old punch card time clock facelift
15. ^'Time Is Money'(PDF). https://www.accelo.com/assets/Uploads/WhitePaperTimeIsMoney.pdf. July 2014.External link in |website= (help)

External links[edit]

Time Clock 10 Minutes

• IBM Time Clocks (PDF files)
• www.timerecorder.de/ (mostly in German, but partly translated into English) is one of the most comprehensive online documentations of the history of time recorders and time clocks