Every ten seconds or so, a voice announces "At the third stroke, it will be [for example] twelve forty-six and ten seconds...", with three beeps following
At the third beep, the time at that point is the time announced previously
Some countries have sponsored time announcements and include that in the message.
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
"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.