16th Feb 1951

Messsrs, Ericsson telephones Ltd
Telephone Works
Beeston (Notts.) England  


For the attention of Mr. R. C. Woods

Dear Sirs,

We regret the long delay in answering your letter, but our expert on the subject, Mr. Hemming Johanason, was ill when it arrived and it was not un'til today that he was able to give his reply, which reads as follows.

The magneto instrument (fig. 117 in Pooles handbook) is the same as No. 375 in Ericsson's catalogue. It is 'the Trade Mark' telephone, called the 'Skeleton type' by the English telephone people. It was constructed by L. M. Ericsson himself in 1884.  Before the hand microtelephone existed, the instrument was provided with an Ericsson 'Spiral microphone' on a swinging arm and an ordinary hand set. From the year 1890, however, all instruments of  this kind had handmicros.  It was introduced in England soon after, and when the National Telephone Company in the year 1698 closed a contract with the Ericsson Company for a delivery of 100,000 telephone sets, a fair'ly big part of this quantity consisted of type 375 table  sets.

As regards the handmicro, it was also constructed in the year 1884 with the spiral microphone as sender and on the first samples an ordinary hand set as receiver. As these part improved the handmicro also improved, and from the year 1890 these instruments had a granulated carbon microphone, with or without capsule and the small receiver with ringing magnets. Fig. 89 in Poole's book shows the polarized ringer in the type 375 table set. After the introduction of Central Battery and Automatic Telephones systems this type of table set was not practicable it is of course made exclusively for magneto systems and the manufacturers had to turn over to more suit'able types.

As regards other types of table set., it is of some interest to remark that the illustration 119 in Poole's book refers to an instrument, also constructed in Stockholm by Ericssons (look at the side plate!). It was copied by i.a. Elektrisk Bureau in Oslo, from which factory a lot of them were delivered to the Glasgow Corporation.  On account of the deliveries to the National Company Ericsson did not like to help their big opponent in Glasgow.

Concerning the battery ringing instrument, fig. 124 in Poole's book, it was constructed in Stockholm by Ericsson in the late 1890's and principally used in telephone plants of smaller extensions. A lot of them, of perhaps a little stronger make, were delivered to the G.P.O. in the years about 1900. 

Yours faithfully,


H. Stenmark  

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