We have a lot to thank Laila Ohlgren for

I watched the above video (turn the sound up at the bottom right to hear the audio) of a millennial trying to use a rotary phone and immediately thought of Laila Ohlgren, the Polhem prize winner. I am lucky in my translation work to learn a great deal about all kinds of subjects and Laila’s brilliant idea has always fascinated me.

If you look at the video you will see that the young boy tries to dial the number first and then lift up the receiver to connect, because that is the way you do it using a mobile phone. On those old phones what you did was lift the handset first to get the ring signal and THEN dial the number. [Interesting side note: phrases such as dial a number, pick up, and hang up come from the days of these old phones. It is also the reason that emergency numbers were easy to dial – 999 or 911. See reason below given by the wonderful Amanda].

The woman who had the brilliant idea to reverse the procedure was engineer Laila Ohlgren, who worked at the Swedish telecommunication authority in the 1970s. This authority was developing mobile phone and cellular tower technology at the time.  They rode around Stockholm trying to make calls and found out that by the time they had dialled the number, they had lost the connection to the cellular tower. So Ms Ohlgren had the brilliant idea of dialling the number first and then connecting to the tower for a signal. And it has been like that ever since.

Laila Ohlgren was employed at Televerket in 1956 to work on the rollout of the Swedish television network. In 1972, when she began working in the Televerket radio development department, she was the only female engineer there. She is remembered for coming up with the idea of first dialing the number before making the call.

As has been pointed out, one of the aims for NMT was that dialing was to work in more or less the same way as for a normal telephone. This meant picking up the handset and then dialing the number. The equipment needed to be familiar to people. But it was not working properly in the field trails: the connection kept breaking.

“It was taking at least 15 seconds to dial a number. During that time a building or a tree could get in the way, so you ended up in a radio shadow, which meant that not all the digits were getting through,” Ohlgren says.

At the beginning of June 1979, just before a decision was to be made about the NMT specifications for the test, Ohlgren got the idea of turning the process around. This broke one of the commandments, which stated that the dialing procedure must be the same as in the fixed network.

“But as each mobile telephone was going to have its own little microprocessor, you could let it store the numbers before it started the call. I thought it would make connections more reliable. You could also use the frequencies better because you did not have to use valuable capacity during the actual dialing,” she recalls.

A quick test with thousands of connections driving around Stockholm during the June Public holiday weekend gave enough statistics to see if this new solution worked. It did.

At the very last minute, before the system specifications were laid down, the numbering system reserved for NMT subscribers was changed from a five-digit one to six digits. After all, there was a possibility that all the five-digit numbers could be used up in the distant future.

In the spring of 2009, Laila Ohlgren won the Swedish Polhem Prize, awarded for top technical innovation.Her idea – to dial the number first and then make the connection – gave NMT significantly more capacity. For operators, it meant an increase of around 25 percent in income for the same investment.






Author: Janet Carr

Fashion, beauty and animal loving language consultant from South Africa living in Stockholm, Sweden.

3 thoughts

  1. On UK rotary phones, 9 is the farthest/longest to dial. I’d always been told that 999 was chosen for the emergency number as it would be easy to locate the number 9 if you couldn’t actually see the dial (because of smoke for example). It’s certainly the longest number to dial.

    1. You are probably correct for all other countries as well Amanda – it has been so long since I have seen a phone dial I must have forgotten. Let me check!

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