Ethel, Pat, Brian and Tim
It was Saturday 18 July 1936 when callers in the London area became the first people in the United Kingdom to dial into the new Post Office Speaking Clock (Mark I) and were able to hear the golden voice of Ethel Cain. In its first year of operation the service logged 13 million calls – over 35,000 a day – and in recent years this figure has risen to an annual 100 million calls.
Accurate to one tenth of a second
With the introduction of a speaking clock up to one hundred callers could listen simultaneously to the time being announced at 10 second intervals. The announcements were accurate to one tenth of a second. After listening for 90 seconds the caller, if they had not wrung off already, would be disconnected automatically.
The words for the speaking clock were first recorded on to a sound film strip and then laid down photographically on to four glass discs, with each individual phrase given its own track within the disc. The actual time announcements were created by photo-electrically selecting appropriate words or phrases into the correct sequence. To play the recorded audio message, a photocell and lamp assembly were indexed to the tracks on the disc so that no physical contact was ever made with the disc. Phrases such as “At the third stroke”, “it will be”, “four”, “o’clock”, “precisely” were thus assembled seamlessly by a mechanism using revolving cams. The mechanism for rotating the discs, for building up the time announcements and for changing from one announcement to another was electrically driven and, when installed in the Holborn telephone exchange, was checked automatically against a time signal transmitted from Greenwich.
The voice of the Speaking Clock
The General Post Office organised an internal competition to select the voice of Speaking Clock No 1.
To find the ‘Girl With The Golden Voice’, Stephen Tallents, the GPO’s publicity director, initially looked to the thousands of female call operators who manned the organisations manual exchanges. Almost all of them would have been young, well spoken girls from the lower middle classes. But even he was surprised by the response he got to his search; 15,000 women entered his competition.
The judges were poet laureate John Masefield, actress Dame Sybil Thorndike and chief BBC announcer Stuart Hibberd.
Only after Ethel Cain had been chosen to record each of the 79 individual phrases required for the new service and her voice had actually been recorded, did it become apparent that she had a minor speech impediment. It was the microphone that picked up a slight ‘whistle’ at the end of each her words, something the judges had clearly not noticed. But it now became a major issue. The problem was solved by laborious manual correction; engineers literally painted out the whistling parts of her speech from the glass discs used in the clock.
Ethel went on to become a Hollywood actress, changing her name to Jane Cain.
The second Speaking Clock
Speaking Clock Mark I was taken out of service in 1963 and replaced by a new transistor version replete with a new voice; that of Pat Simmons.
This second machine, was labelled the Mark III model, owing to an earlier Mark II model being developed in Britain for the Australian Speaking Clock, but never adopted in Britain itself.
Britain’s second Speaking Clock (Mark III) was constructed quite differently. Pat’s voice was recorded on to a magnetic drum and picked up by magnetic sensing heads operated by cams that moved along the drum every four minutes. The accuracy of the machine was controlled by a quartz crystal oscillator located within a rack behind. There were, in fact, two speaking clocks mounted on the same base. But the second clock only came into operation if a fault occurred on the first, or if it needed servicing.
The third Speaking Clock
In 1985 Britain’s second Speaking Clock (Mark III) was superseded by a digital version (Mark IV),which used a built-in crystal oscillator and microprocessor logic control. It transmitted the Speaking Clock’s third voice; that of Brian Cobby. The clock operated until 2001 when it was superseded by the current Speaking Clock Model. The BHI Museum were delighted to receive the 1985-2001 machine, donated by BT from when removed from its original Liverpool location, in October 2016.
What’s the time TIM?
If they were in one of the major UK cities initial subscribers to the system could access the speaking clock by dialing the letters TIM, which corresponded to the digits 846. (Other areas dialed 952.) The engineers had conceived TIM as simple shorthand for time, but it soon became a brand as the speaking clock service became universally known as Tim.
Since the early 1990s, the dialled number has become 123 and BT call the service Timeline. But individuals of ‘a certain age’ still refer to the service as Tim. Much to the bemusement of the younger generation.
Britain’s First (Mark I), Second (Mark III) and Third (Mark IV) Speaking Clocks can be seen at the BHI Museum Trust at Upton Hall. Find out more about the donation of the Mark IV model here.