"At the third stroke, it will be three thirty three and forty seconds ..
These are done in 10 second increments and the beep is 1 kHz.
Mechanical speaking clock at the Victorian Telecommunications Museum
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 globes in the optical pickups from the glass disk recordings
When Time and 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.
Assmann digital speaking clock at the Victorian Telecommunications Museum
This mechanical system was replaced with a digital system in 1990