Rapid technological development
The first Ericsson telephone in 1880 used a battery and a bell to signal an incoming call. In 1882, Lars Magnus presented an improved version with a magnetic inductor and a polarized bell, and with all the components neatly integrated into a compact unit. With its characteristic design, this wall telephone soon became familiar all over the world; copies were often made and referred to as Swedish pattern, Schwedische Type and the like.
The microphone was also being improved all the time. After the helical microphone came the simpler carbon-rod microphone, used by L.M. Ericsson & Co. from 1886, to be followed by the superior carbon-powder microphone in 1888.
Another step involved combining the earpiece and the microphone to form what was called a “hand-micro-telephone”, or handset. This innovation was born in 1884 when two engineers, Anton Avén and Leonard Lundqvist, were carrying out tests on behalf of SAT. Impatient with having to handle a separate microphone and earpiece, they joined the two together by tying them with string to a wooden handle. Lars Magnus adopted the idea and designed the first such handset, an idea which then spread to many parts of the globe.
The major exception was the Bell Company, which continued with separate earpieces and microphones for several decades. Hemming Johansson commented 50 years later that: “Telephone users today will certainly fail to understand the attitude of the Americans in this area.” It was hardly due to any lack of appreciation of the handset’s benefits: “Quite the opposite, one could justifiably claim. The introduction of handsets in all the Bell Company systems would have prompted so widespread a demand from their enormous numbers of subscribers to be able to partake of such a benefit that the company would hardly have been able to satisfy it.”
L.M. Ericsson & Co. supplied SAT’s telephone exchanges with what were called multiple switchboards of a new type in which each switchboard operator had access to all the cables connected to the exchange. Previously the operators had to shout to each other if connections were made from one switchboard to another, which made the work more complicated as the number of subscribers rose. The multiple position exchange was an American invention but L.M. Ericsson & Co. made its own version from 1884 onwards “on the basis of hints in a foreign journal”, to quote the history of SAT’s first 10 years.
The combination of supplier and client was a fortunate one. “Cedergren persisted and Ericsson was suitably skeptical,” is how the director of Stockholm’s Technical Museum, Anders Lindeberg-Lindvet, expressed it. Another example can be found in the automatic changeover switches presented by the pair in 1883, and the semi-automatic exchanges they soon developed. This enabled a group of subscribers in a village, for example, to manage with fewer lines. A “manipulator” that transmitted impulses allowed a switchboard operator to restore the line once a connection had been made.
From the very beginning of their collaboration, Cedergren and Ericsson were looking for technological solutions that could reduce the amount of human intervention required.
SAT continued to acquire large numbers of subscribers during the 1880s. Even though the management believed it had planned substantial capacity, within just three years it had become necessary to build a new central telephone office: the locally famous telephone tower on Malmskillnadsgatan inaugurated by King Oscar II before a large audience on July 12, 1887. In connection with the move, SAT introduced a new procedure in which callers had to ask for the telephone number they wanted. Until then, the name of the subscriber had been enough, but now it was considered impossible for switchboard operators to keep track of the names of 4,000 subscribers.
Author: Svenolof Karlsson & Anders Lugn
Work on telephone lines on a city roof in Sweden 1896. Mainly seamen, used to working high above the ground (or sea level), were recruited for this kind of work.
The telephone tower of Stockholms Allmänna Telefon AB seen from the square of Brunkebergstorg, 1900s.
Sweden, 1900s, Street Cable work