A speaking clock or talking clock is a live or recorded human voice service, usually accessed by telephone, that gives the correct time. The first telephone speaking clock service was introduced in France, in association with the Paris Observatory, on 14 February 1933.
The format of the service is similar to that of radio time signal services. At set intervals (e.g. ten seconds) a voice announces (for example) "At the third stroke, the time will be twelve forty-six and ten seconds...", with three beeps following. Some countries have sponsored time announcements and include the sponsor's name in the message.
- 1 ASEAN
- 2 Argentina
- 3 Australia
- 4 Austria
- 5 Barbados
- 6 Belgium
- 7 Brazil
- 8 Canada
- 9 Chile
- 10 Czech Republic
- 11 Denmark
- 12 Finland
- 13 France
- 14 Germany
- 15 Greece
- 16 Iceland
- 17 Iran
- 18 Ireland
- 19 Japan
- 20 Latvia
- 21 Netherlands
- 22 Norway
- 23 Poland
- 24 Russia
- 25 South Africa
- 26 Spain
- 27 Sri Lanka
- 28 Sweden
- 29 Switzerland
- 30 Taiwan
- 31 Ukraine
- 32 United Kingdom
- 33 United States
- 34 Other countries
- 35 In popular culture
- 36 See also
- 37 References
- 38 External links
In 1995, the ASEAN has set up nine speaking clocks.
- Malaysia 1051 (within Kuala Lumpur), 03-1051 (from other states), +60-3-1051 (from other countries), 1052 (English)
- Singapore 171 (English) (1711 if called from other ASEAN countries, +65-171 from other countries), 172 (Chinese), 173 (Tamil)
- Thailand 181 (1811 if called from other ASEAN countries, +66-181 from other countries), 182 for English
The voice is computer-generated in ten languages: Chinese (Singapore), English (every country), Indonesian (Indonesia), Khmer (Cambodia), Lao (Laos), Malay (Malaysia, Brunei), Tagalog (Philippines), Tamil (Singapore), Thai (Thailand) and Vietnamese (Vietnam).
In Argentina, users can reach the automatic time service dialing 113 from almost every fixed line operator.
In Australia, the number 1194 gives the speaking clock in all areas and from all providers. It is always the current time from where the call originates. A male voice says "At the third stroke, it will be (hours) (minutes) and (seconds) seconds/precisely. (three beeps)" e.g. "At the third stroke, it will be three thirty three and forty seconds ... beep beep beep". These are done in 10 second increments and the beep is 1 kHz.
Prior to automatic systems, the subscriber rang an operator who would quote the time from a central clock in the exchange with a phrase such as "The time by the exchange clock is...". This was not precise and the operator could not always answer when the subscriber wanted. In 1954, British-made systems were installed in Melbourne and Sydney. The mechanical speaking clock used rotating glass discs where different parts of the time were recorded on the disc. A synchronous motor drove the disc with the driving source derived from a 5 MHz Quartz Oscillator via a multi stage valve divider. This was amplified to give sufficient impetus to drive the motor. Because of the low torque available, a hand wheel was used to spin the motor on start up. The voice was provided by Gordon Gow. The units were designed for continuous operation. Both units in Melbourne and Sydney were run in tandem (primary and backup). For daylight saving time changes, one would be on line while the second was advanced or delayed by one hour and at the 02:00:00 Australian Eastern Standard time, would be switched over to the standby unit.
As well as the speaking clocks, there was ancillary equipment to provide timing signals, 1 pulse per second, 8 pulses per minute and 8 pulses per hour. The Time and Frequency Standards Section in the PMG Research Laboratories at 59 Little Collins Street, Melbourne maintained the frequency checks to ensure that the system was "on time". From a maintenance point of view, the most important part of the mechanical clocks was to ensure that they were well oiled to minimise wear on the cams and to replace blown bulbs in the optical pickups from the glass disk recordings. When Time & Frequency Standards moved from 59 Collins Street to Clayton, the control signals were duplicated and a second bank of Caesium Beam Primary standards installed so the cutover was transparent with no loss of service.
This mechanical system was replaced with a digital system in 1990. Each speaking clock ensemble consisted of two announcing units (Zag 500), a supervisory unit (CCU 500), two phase-locked oscillators, two pulse distribution units, a Civil Time Receiver (plus a spare), and two or four Computime 1200 baud modems. The voice was provided by Richard Peach, a former ABC broadcaster. The various components were sent for commercial production after a working prototype was built in the Telstra Research Laboratory (TRL). Assmann Australia used a German announcing unit and built a supervisory unit to TRL specifications. Design 2000 incorporated TRL oscillators in the phase locked oscillator units designed at TRL and controlled by two tone from the Telstra Caesium beam frequency standards. Ged Company built civil time receivers. The civil time code generators and two tone generators were designed and built within TRL. The changeover occurred at 11:59:52, September 12, 1990.
Each state capital had a digital speaking clock for the local time of day with one access number for all Australia, 1194. In 2002 the Telstra 1194 service was migrated to Informatel (which uses its own digital technology, in conjunction with the National Measurement Institute — but kept the original voice of Richard Peach), whilst the other time services (e.g. hourly pips to radio stations) were retained as a service by Telstra. In May 2006 the remaining Telstra services were withdrawn and the digital hardware was decommissioned. The 1194 service, though no longer provided by Telstra, is still operated by Informatel in partnership with Telstra.
In Austria, the speaking clock ("Zeitansage", which literally means "time announcement") can be reached at 0810 00 1503 since 2009. A recorded female voice says (for instance): "Es wird mit dem Summerton 15 Uhr, 53 Minuten und 10 Sekunden", meaning "At the buzzing tone, the time will be 15 hours, 53 minutes and 10 seconds", followed by a short pause and a 1 kHz, 0.25 seconds long beep (even though the announcement "buzzing tone" suggests otherwise). The time is announced in 10 second intervals. Before 2009, the speaking clock was available by dialing 1503. Until there, the voice was generated by an Ansmann ZAG500, which was also used in Australia. This has been replaced by a voice server.
In Barbados, daily time and temperature conditions are provided by the firm Accuweather and can obtained by the number +1.246.976.8463. Daily weather conditions are now at a separate number +1.246.976.2376.
In Belgium, the speaking clock can be reached on the numbers 1200 (Dutch language), 1300 (French language), and 1400 (German language).
In Brazil, the user can access a non-free Speaking clock service, dialing the "130" number.
NRC time is referred to its primary cesium atomic clocks designed, built, and maintained at the NRC time standards laboratory in Ottawa.
The NRC provides a Telephone Talking Clock service; voice announcements of Eastern Time are made every 10 seconds, followed by a tone indicating the exact time. This service is available to the general public by dialing +1 613 745-1576 for English service and +1 613 745-9426 for French service. Long-distance charges apply for those calling from outside the Ottawa/Gatineau area. The voices of the time announcements are Harry Mannis in English and Simon Durivage in French.
The Hydrographic and Oceanographic Service of the Chilean Navy provides a toll-free speaking clock at +56 (800) 800 780.
The Danish telephone company KTAS introduced the automated time service Frøken Klokken in 1939, originally voiced by telephonist Anna Edith Sommer-Jensen (1918–2008). In 1970, a new system used the voice recordings of Marianne Germers. The service was digitised in 1993.
The TDC Speaking Clock can be heard by calling +45 70 10 11 55 outside Denmark and on 70 10 11 55 within Denmark.
In Finland the speaking clock service is known as Neiti Aika in Finnish or Fröken Tid in Swedish, both of which literally translate as 'Miss Time'. The first Neiti Aika service was started in 1936 and was the first automated phone service in Finland. The service is provided by regional phone companies and can be reached by dialling 10061 in the whole country. The voice of the speaking clock can be male or female depending on whose phone company service you are using. Nowadays the use of the Neiti Aika service has decreased pretty much to null and the press officer of Auria, the regional phone company of Turku, stated in an article of the Turun Sanomat newspaper that when the company started the service in 1938 it was used 352,310 times in its starting year compared to 1300 times in September 2006.
In France, the speaking clock (horloge parlante) has been in service since 14 February 1933. It is available on 36.99 from within France, and was formerly available from overseas by dialing +33 8.36.99.xx.xx (where x could be anything). However, since September 2011 a call placed from outside of France or its territories yields only a recording indicating that the number is no longer available.
In Germany, the speaking clock is available by dialing 0180 4 100 100.
A speaking clock in Hamburg is available by dialing
- 040 - 42 89 90 (domestic calls)
- +49 - 40 - 42 89 90 (from abroad)
Just the normal fixed line phone rate applies.
In Greece, the speaking clock can be heard by calling 14814 
The Icelandic speaking clock service ("klukkan"), provided by Síminn, can be reached by dialing (+354) 155.
All over the country, calling 119 will connect people to the speaking clock in Persian language.
The format used is a message at 10 second intervals saying: "At the signal it will be, HH:MM and XX seconds" followed by a short high pitched beep.
The Japanese telephone company NTT provides a non-free speaking clock on the nationally universal number 117.
The non-free Lattelecom speaking clock is provided in both Latvian and Russian languages and can be reached by dialing either (+371) 82154 or 82174, respectively. The precise time is given immediately upon connection, rather than after a certain signal.
In 1930, a system was installed in the Haarlem telephone exchange (automated in 1925) which indicated the time using series of tones.
In 1934, electronic engineer and inventor F.H. Leeuwrik was requested to build a speaking clock for the municipal telephone service of The Hague. His experience with sound film made him decide to use optically recorded speech, looping on a large drum. There were loops for the hours and for the minutes, each one read with a photodetector. Every minute the clock gave an electric pulse, causing the mechanism to shift to the next minute. Every hour, the minute mechanism was reset (and every day the hour mechanism), the clock was accurate within one minute only. The female voice was provided by the then 24-year-old school teacher Cor Hoogendam, hence the machine was nicknamed Tante Cor (Aunt Cor). The speaking clock came into service at November 9, 1934 and could be reached by dialing 393131. The service became so popular, that in 1935 a second machine was ordered and built. In total F.H. Leeuwrik built 19 machines, one for each telephone district. Starting with the 's-Hertogenbosch exchange in 1941, the number was gradually harmonized nationwide to 002 (or K 02) for all automated exchanges. Even during the Nazi occupation in World War II, the speaking clock was called over two million times a year. During World War II, 12 machines were destroyed and rebuilt after the War by the inventor himself.
In 1969 this system was decommissioned and replaced by a machine that looked like a record player with three pick-up arms. The speaking clock was now much more accurate, telling the time in 10 second intervals followed by a beep, indicating the precise moment. The text was spoken by actress Willie Brill and had the following format: "Bij de volgende toon is het .. uur, .. minuten en .. seconden" (at the following tone, it is .. hour, .. minutes and .. seconds). The service was now called over 130 million times a year.
Finally, in April 1992, the whole machinery has been replaced by a digital machine with no moving parts. The (digitized) voice has been provided by actress Joke Driessen and the clock is being kept accurate by German longwave transmitter DCF77. In accordance with international guidelines (the double-zero should be used as an international prefix), the number 002 was changed on 3 December 1990 to 06-8002, and later to 0900-8002. Though nowadays many people have digital wrist watches, mobile phones or computers telling the time accurately, the service is still being called approximately four million times a year, especially around New Year's Eve and when the daylight saving time changes.
The speaking clock (Norwegian: Frøken Ur, meaning Miss Clock) in Norway was in service between 1932 and 15 January 2007 14h00 local time. The service could be reached by dialling 09170 (1999–2007), and 170 (until 1999). Of women who contributed with their voices for the service were actress Randi Brennes (–1992) and Kristin Johnson (1992–2007). When the service ceased it still got about 2000–3000 calls per month.
The speaking clock in Poland is known as Zegarynka which means the clock girl. The service became first available in 1936 and it was using a device invented and patented in Poland. It was speaking with the recorded voice of actress Lidia Wysocka. The first cities to be equipped with this device were Katowice, Warszawa (dialing number 05), Gdynia, Toruń and Kraków (July 1936).
For many years the number was 926, but due to the EU regulations reserving all 3-digit numbers for emergency services only, it was changed in the early 2000s. The connection is charged on a per-minute basis. In 2009 the number was changed to 19226.
Since 1936, the voiced has been changed twice.
To hear the current time in Russia you dial 100 or 060, depending on the city where this service is available. These calls are free if made from non-mobile phones. In Moscow, the Speaking Clock number is 100 if dialed from within the city, or +7-495-100-xxxx from other countries (where x can be anything). At one time in Moscow there were advertisements before and after the announcement of the current time; this practice has since ceased.
The speaking clock in South Africa is reached by dialling 1026 from fixed or mobile networks and consists of a female voice reading the time in 24-hour format, alternating between Afrikaans and English. All of South Africa is in the time zone GMT+2 without any daylight saving time so the speaking clock is the same all over the country.
Sri Lanka Telecom provides a Speaking Clock service in three languages.
- 1292 - Sinhala
- 1293 - Tamil
- 1294 - English
More details can be found on SLT telephone directories.
The speaking clock (Swedish: Fröken Ur, literally Miss Clock) in Sweden has been in service since 6 October 1934, and can be reached by dialling 90510 (+46 33 90510 from outside Sweden). Four women have contributed with their voices for the service: Eva Ulvby (1934–1956), Berit Hofling (1956–1968), Ebba Beckman (1968–2000), Johanna Hermann Lundberg (née Östlund) (2000-).
The speaking clock can be reached under 161.
A voice announces:
- "At the third stroke, the time from BT will be (hour) (minute) and (second) seconds"
For times that are an exact minute, "precisely" is substituted for the seconds portion of the announcement. Similarly, announcements for times between the hour and one minute past the hour substitute "o'clock" for the (zero) minutes. Other operators run their own speaking clocks, with broadly similar formats, or redirect to BT's service.
A speaking clock service was first introduced in Britain on July 24, 1936. The mechanism used was an array of motors, glass discs, photocells and valves which took up the floorspace of a small room. The voice was that of London telephonist, Ethel Jane Cain, who had won a prize of 10 guineas in a competition to find the right voice. Cain's voice was recorded optically onto the glass disks in a similar way to a film soundtrack. The service was obtained by dialling the letters TIM (846) on a dial telephone, and hence the service was often colloquially referred to as "Tim". However this code was only used in the telephone systems of the cities of London, Birmingham, Edinburgh, Glasgow, Liverpool and Manchester. Other areas initially dialled 952 but with the introduction of Subscriber Trunk Dialling it was changed to 80 and later 8081 as more 'recorded services' were introduced and was standardised to 123 by the early 1990s.
The time announcements were made by playing short, recorded phrases or words in the correct sequence. In an interview with Manchester Radio in 1957 Miss Cain said:
The way I recorded it was in jerks as it were. I said: "At the Third Stroke" (that does for all the times), and then I counted from One, Two, Three, Four, for the hours, we even went as far as twenty-four, in case the twenty-four hour clock should need to be used, and then I said "...and ten seconds, and twenty seconds, and thirty, forty, fifty seconds", and "o'clock" and "precisely". The famous "precisely". So what you hear is "At the Third Stroke it will be one, twenty-one and forty seconds".
In 1963, the original device was replaced by more modern recording technology using a magnetic drum. The company that manufactured the rotating magnetic drum part of the Speaking Clock was Roberts & Armstrong (Engineers) Ltd of North Wembley. They took on the licence from the British Post Office to manufacture complete clocks for the telecommunications authorities of Denmark, Sweden and the Republic of Ireland, and a third (spare) clock for the British Post Office. This latter was installed in Bow Street, London. The European clocks were modified for the 24 hour system by lengthening the drum and adding extra heads. Roberts & Armstrong subcontracted the electronic aspects to the Synchronome Company of Westbury. The clocks were designed to run non-stop for 20 years. This system gave way to the present digital system in 1984, which uses a built-in crystal oscillator and microprocessor logic control. The complete apparatus comprises solid-state microchips, occupies no more shelf space than a small suitcase and has no moving parts at all. The BT service is assured to be accurate to five thousandths of a second.
In 1986, BT allowed Accurist to sponsor its franchise, the first time a sponsor had been used for the service. In the latter years of this sponsorship, it cost 30 pence to call the speaking clock. Accurist announced its withdrawal from the deal and the launch of an online "British Real Time" website on 24 August 2008.
During the Cold War, the British Telecom speaking clock network was designed to be used in case of nuclear attack to broadcast messages from Strike Command at RAF High Wycombe to HANDEL units at regional police stations. From there, automatic warning sirens could be started and alerts sent to civil defence volunteers equipped with manual warning devices. The rationale for using an existing rather than a dedicated system was that it was effectively under test at all times, rather than being activated (and possibly found to be faulty) only in the event of war. The signals to automatic sirens were sent down the wires of individual (unaware) subscribers for the same reason — a customer would report any fault as soon as it occurred, whereas a problem with a dedicated line would not be noticed until it was needed.
A version of the speaking clock was also used on recordings of proceedings at the Houses of Parliament made by the BBC Parliament Unit, partly as a time reference and partly to prevent editing. On a stereo recording, one track was used for the sound and the other for an endless recording of the speaking clock — without the pips, as these were found to cause interference.
On the occasion of a leap second, such as at 23:59:60 on December 31, 2005, there is a one second pause before the beeps, thus keeping the speaking clock in sync with Coordinated Universal Time. The current source of UK time is provided, though not monitored, by the National Physical Laboratory, UK. Since 2003, the British speaking clock has changed voices four times. Almost all changes have occurred on days when the clocks have switched from standard time to daylight saving time or vice versa. This is due to the fact that 123 is most commonly dialled on these days.
The BT Speaking Clock receives around 60 million calls a year.
A separate, non-BT service to access a speaking clock using the voice of Pat Simmons, is available on 020 3598 2801, or dialling from abroad +44 20 3598 2801.  However the calls it can receive at any one time is limited.
List of voices heard on the British "BT Speaking Clock"
- Ethel Jane Cain, first permanent voice: from July 24, 1936 to 1963.
- Pat Simmons, second permanent voice: from 1963 to April 2, 1985 (may still be heard).
- Brian Cobby, third permanent voice: from April 2, 1985 to April 2, 2007.
- Lenny Henry, comedian, temporary voice for Comic Relief: from March 10 to March 23, 2003.
- Alicia Roland, 12-year-old schoolgirl, temporary voice for the children's charity ChildLine, from October 13 to October 20, 2003, having won a BBC TV Newsround competition and stating, before announcing the time, "It's time to listen to young people".
- Sara Mendes da Costa, fourth permanent voice: from April 2, 2007.
- Mae Whitman, temporary voice as part of a deal to promote the Disney production of Tinker Bell, for three months from 26 October 2008 until 2 February 2009.
- UK celebrities Kimberley Walsh, Cheryl Cole, Gary Barlow, Chris Moyles, and Fearne Cotton for Comic Relief charity: from 3 February to 23 March 2009.
- UK celebrities David Walliams, Gary Barlow, Chris Moyles, Kimberley Walsh, Fearne Cotton and a mystery voice for Sport Relief charity from 7 March to 9 April 2012. 
- Clare Balding temporary voice for Comic Relief from 12 February to 15 March 2013 (with the help of a barking dog, time announced as "at the third woof".)
- Davina McCall temporary voice for Sport Relief from 27 January to 23 March 2014.
In the United States, this service was typically known as the "Time of Day" service, with the term "speaking clock" never used. Occasionally it would be called "Time and Temperature" or simply "Time." However, the service had been phased out in most states (California, Nevada and Connecticut still maintain service). AT&T discontinued its California service in September 2007, citing the widespread availability of sources such as mobile phones and computers.[vague]
For all area codes in Northern California, the reserved exchange was 767, and was often indicated by its phoneword, POPCORN. In other locations, different telephone exchanges are or were used for the speaking clock service. In these areas, the numbers were usually quoted with the -xxxx, -2525, -1212, or -1234 ending. For example,
- 853 was the reserved exchange in Southern California.
- 622 was the reserved exchange in Florida.
- 637 (MEridian 7) is the reserved exchange in Boston and New York City.
- 846 is the reserved exchange in Philadelphia.
- 844 (TIm e 4) was the reserved exchange in Washington D.C., with the officially published number of TIme 4-2525. This clock was usually the most accurate of the clocks operated by the local telephone companies. The service was discontinued in 2011.
- 936 (WEather 6) was used in Boston, Washington D.C., and Toledo, Ohio for weather information.
- In Washington, the officially published number was WEather 6-1212.
Various other numbers were used in other localities.
- In Wisconsin, the former Wisconsin Bell reserved the ending numbers -0123 in the dominant exchange for a city for time and temperature information.
- (203) 777-4647 (203-SPRINGS), New Haven, Connecticut is still an active time of day service.
- (541) 917-6885 Speaking Clock, Albany, Oregon "the time is ..."
- (503) 485-8905 Speaking Clock, Salem, Oregon "the time is ..."
- (919) 468-8463 468-TIME Service, Cary, North Carolina. Service is working as of December 2013.
- (919) 249-1130 Apex, North Carolina Time & Temperature. Time/Temperature/Weather Service is working as of December. 2013.
- (919) 362-1226 Apex, North Carolina. Apex WeatherNow! Time/Temperature/Weather Service is working as of December 2013.
- (408) 767-2676 (408-POPCORN). California Time of Day using phoneword "POPCORN" in Area Code 408.
Many shortwave radio time signal services provide speaking clock services, such as WWV (voiced by John Doyle) and WWVH (voiced by Jane Barbe), operated by the National Institute of Standards and Technology from the United States of America. To avoid disruption with devices that rely on the accurate timings and placement of the service tones from the radio, the voice recording is "notched" clear of some of the tones.
The time as provided by WWV is also available by telephone, by calling +1 303 499-7111. WWVH (an auxiliary location in Hawaii) is available at +1 808 335-4363.
The time as provided by Tellme voice portal is available by dialing non-toll-free numbers 330-247-7411 or 408-752-8052.
Electronic speaking clocks and wristwatches are available, many marketed to the visually impaired.
Many telephone answering machines and similar devices include a speaking clock capability so they can announce the time when a message was received.
- In Cambodia, the speaking clock number is 107 for Phnom Penh and 023-107 for other provinces. The call rate is KHR 300 per minute in Phnom Penh.
- In Malaysia, there are two speaking clocks, the first one is 1051, which is owned by SIRIM Berhad, another one, 181, owned by LKS Group, a private group of companies. Both are available only in Malay language.
- In Thailand, the number of speaking clock is 181.
In popular culture
- At the start of the Fawlty Towers episode, "The Psychiatrist", Basil calls the operator to ask why the Speaking Clock was engaged for ten minutes.
- The Vangelis song "Pulstar" ends with a recording of the Speaking Clock.
- The Orchestral Manoeuvres in the Dark song "Time Zones" from their 1983 album Dazzle Ships features recordings from various Speaking Clock services worldwide.
- In an episode of Cartoon Network's Johnny Bravo, "Bearly Enough Time", Chronos the bear calls an operator who tells him a time that according to him was wrong, and then he tried to correct it.
Literature and radio plays
- The radio drama MEridian 7-1212 by Irving Reis, produced by the Columbia Workshop August 24, 1939, (available from the Internet Archive), dealt with the New York Telephone time service at a time when the announcements were still read live.
- Tom Stoppard wrote a radio play, If You're Glad I'll Be Frank, where a bus driver thought his wife was the speaking clock. During the play it is revealed that his wife really is the speaking clock — but reading the time live, 24 hours a day, instead of having it done by a machine.
- In Little Miss Chatterbox by Roger Hargreaves, the title character has many jobs but is fired from each one of them due to talking all the time. At the end of the story, Little Miss Chatterbox finds the perfect job as the Speaking Clock.
- The character Ford Prefect in Douglas Adams' So Long, and Thanks for All the Fish played an elaborate prank by using a ship's advanced telecommunications system to place an expensive intergalactic call to the London Speaking Clock, keeping the call indefinitely connected in an attempt to run up the ship's phone bill.
- Adrian Edmondson's book How To Be a Complete Bastard includes a spoof British Telecom advert saying "Make Someone Happy (Us)" where it requests readers to go to their neighbours house when they have gone on holiday and call the Melbourne Speaking Clock in Australia, leave the 'phone off the hook and then go on holiday themselves.
- (fr) Paris Observatory
- Telstra Research Laboratory Internal web page
- "O2 | Important numbers - Contact us". O2.cz. Retrieved 2013-11-13.
- Helsingin Sanomat / Kulttuuri, 3.5.2002, Sellainen on puhelin (in finnish)
- Turun Sanomat, 29.10.2004, Neiti Aika vaihtui herraksi Satakunnassa (in finnish)
- Turun Sanomat, 29.10.2006, Ajalla monta näyttäjää Turussa - Oi aikoja, oi tapoja tsekata se (in finnish)
- "Speaking clock Video". Speaking-clock.com. Retrieved 2013-11-13.
- pareizs laiks | Lattelecom
- Ik zal u doorverbinden, C.J. Wulffraat et al., in Honderd jaar telefoon, ed. J.H. Schuilenga et al., Staatsbedrijf der Posterijen, Telegrafie en Telefonie, 's-Gravenhage, 1981, p. 215
- 06 straks ook voor tijd en weerbericht, Het Vrije Volk, 16 november 1990
- Telefonische tijdmelders, Museum voor Communicatie, The Hague, Netherlands
- Spis abonentów warszawskiej sieci telefonów Polskiej Akcyjnej Spółki Telefonicznej i rządowej warszawskiej sieci okręgowej 1938/1939. Warszawa. 1938.
- Brzoza, Czesław (1998). Kraków między wojnami. Kraków: Towarzystwo Sympatyków Historii. ISBN 83-909631-0-8.
- "SP ensures that Fröken Ur always tells the right time". Sp.se. Retrieved 2013-11-13.
- see:[www.telephonesuk.co.uk/speaking_clock.htm Telephones UK:The Speaking Clock] Retrieved on 20 October 2008
- Recording the first speaking clock, 1936 Retrieved on 20 October 2008
- The Speaking Clock
- The Guardian Wainwright, W. [www.guardian.co.uk/business/2008/aug/25/btgroup Speaking clock sponsor says it's time for change] Retrieved on 20 October 2008
- UKWMO early warning system Retrieved on 20 October 2008
- What is the accuracy of the 'speaking clock'?
- "Speaking Clock at telephonesuk.co.uk".
- "I am the new speaking clock voice". BBC News. 2003-10-13. Retrieved 2010-05-23.
- BBC News: Speaking Clock gets a new voice Retrieved on 20 October 2008
- "Tinker Bell Voices Speaking Clock". BBC News. 2008-10-24. Retrieved 2010-01-04.
- BT provides celebrity climb sponsorship, Marketing Week, January 16, 2009
- "Channel 4 News - Latest UK & World News | Videos | Special Reports - Channel 4 News". Channel4.com. Retrieved 2013-11-13.
- "BT news releases". Btplc.com. Retrieved 2013-11-13.
- "Clare balding becomes the new voice of BT’s speaking clock to raise money for comic relief" at btplc.com
- "Davina’s going beyond breaking point!" at bt.com
- Lazarus, David (August 29, 2007). "Time of day calling it quits at AT&T". Los Angeles Times. Retrieved July 22, 2011.
- Verizon pulling plug on time, weather services
- "ประวัติการรักษาเวลามาตรฐานประเทศไทย". Hydrographic Department, Royal Thai Navy (HDRTN). Retrieved 2013-07-31.(Thai)