Telstra Research Laboratories
Speaking Clock (1990)


About the video
TRL Cast


Delivery & Installation (Nov 1954) video (sc-50s.mpg ~50Mb 04:51) - original film of Speaking Clock arrival in Australia.
Speaking Clock installed at City West Stock Exchange Melbourne video (sc-old.mpg ~13Mb 01:18)
The Third Stroke (The3rdStroke.mpg ~28Mb 02:50) A professionally produced spoof on “The Third Stroke”.
Changeover from old to new speaking clock video (sc-old-new.mpg ~19Mb 01:51) - Sept 1990
Ch9 News item video (sc-ch9.mpg ~13Mb 01:20) - Ch9 news with Brian Henderson - Sept 1990)
Ch2 News item video (sc-ch2.mpg ~26Mb 02:34) - Ch2 news with Mary Delahunty (inc. other footage) - Sept 1990

About the video

The "Speaking Clock " is a system that "speaks" the time to a telephone subscriber who requires a time check.

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

The first automatic Speaking Clock was introduced in the USA in 1927. In 1954, British made systems were installed in Melbourne and Sydney. These were replaced with digital systems in 1990.

These video clips trace the history of the Speaking Clock in Australia and the role played by the Research Laboratories

Further Information

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 units were designed for continuous operation. Both units in Melbourne & Sydney were run in tandem (primary & backup).

For Daylight Saving changes, one would be on line while the second was advanced or retarded 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 & 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 globes 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.

The New Digital Speaking Clock.

This project was was initiated in the Telstra Research Laboratories (TRL) by Ron L Trainor and worked on by Peter Bernard and Jim Colvin on the newly emerging digital speech processes.

TRL had its own resident Crystal Grinder, John Freeman, who made the ovened quartz oscillators used at each Speaking Clock site.

These had parts in 10 to the 10 frequency stability. Andrew Doherty assisted. Ken Bassett tested the oscillator assemblies.

Bruce Ratcliff designed the Civil Time Code transmitter to link each unit.

Russell Yates and Ben Juska operated the Caesium Beam frequency Standards using Omega reception and the occasional "Flying Clock" from the United States Naval Observatory.

Each Speaking Clock ensemble consists 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 various components were sent for commercial production after a working prototype was built in the labs. 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 & controlled by two tone from the Telstra Caesium Beam Frequency Standards.

Ged Company built Civil Time Receivers.

John Baldock, Jim Colvin and Ken Bassett tested and got the manufacturers to repair defects as detected.

The Civil Time Code generators and two tone generators were designed & built within TRL.

Each State Capital has a Digital Speaking clock for the local time of day with one access number Australia wide, 1194.

Legal Traceability of Time

TRL has had a close working relationship with the National Measurement Laboratory and through the exchange of data have a traceable link to provide Time of Day services. TRL has operated this facility as a Secondary Standard under the National Standards Commission and NML.

The Time & Frequency Standards run by TRL provided a NATA certified Calibration laboratory for Time Interval & Frequency.

Via the Speaking Clock, Computime, TV Sync Pulse measurements & GPS, TRL has provided a traceable Frequency link for other Victorian Calibration Laboratories.

Rob Harris was the principle NATA signatory.

Telstra Announces that the Speaking Clock will Close

"Telstra's time services platform, more commonly known as Telstra's speaking clock, finally reached the end of its lifecycle. After providing a variety of time services for more than 20 years, Telstra decided that from 15 March 2006 it will exit its remaining speaking clock continuous feeds Civil Time, 1 kHz, Two Tone, Time Pips and Computime.

From that
date, Informatel made a variety of these time services available commercially. Informatel is an Australian-based service provider which provided Telstra's publicly available 'Dial-It' 1194 Time Service. Telstra decided to exit its remaining time services because the existing platform has reached the end of its lifecycle due to aged infrastructure and equipment. Furthermore, modern alternatives have superseded the technology used in the existing platform and these alternatives are able to provide more efficient and reliable time services."

up to the top of the page TRL Cast

Delivery & Installation (Nov 1954) video

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Speaking Clock installed at City West Stock Exchange Melbourne video

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Changeover from old to new speaking clock video

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Ch9 News item video

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Ch2 News item video

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Thanks to Graham Lucas for loan of video from his personal collection, his recollections and descriptions above.

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Last updated: 1 April, 2003