Stromberg Carlson

Alfred Stromberg and Androv Carlson were immigrants from Sweden who worked for the Chicago Bell Telephone Company. They were aware of the deficiencies of the telephone as used by the American Bell company, and believed that they could do better. Unlike many other inventors of that period, they did not try to find an alternative to the carbon transmitters in use, but bided their time until American Bell's patents expired.

In 1894 they left Chicago Bell and formed a partnership whose goal was clearly stated - to build a better telephone.

The market at this time gave them a good business opportunity. American Bell was expanding at a rapid rate, but the capital cost of providing lines, exchanges and telephones meant that it could not afford to service rural areas that would not be economic in the short term. Many small independent companies were coming into existence to fill this market, and they needed a supply of reliable telephones. Stromberg Carlson, based in Chicago, set out to fill this need.



Rural people needed a reliable phone. The small companies could not afford a large service crew, and the repair staff could have to travel long distances between faults. American Bell was working on improving its manufacturing quality, but its phones were still better suited to shorter urban telephone lines. Because of the quality and reliability of its phones in rural areas, Stromberg Carlson became known as "the farmer's friend".


Left: Stromberg Carlson rural sales brochure


As an example, their first phone was a fat-bodied candlestick model. It used an electromagnetic transmitter rather than the more usual carbon transmitters. This gave two advantages - no problems with packing of carbon granules, and a higher voltage could be used on longer lines without burning out the transmitter.


Left: Original receiver style

Right: Enclosed receiver




The receiver was described in McMeen and Miller's "Telephony" :
"The single coil is wound on an E-shaped core built up of silicon steel laminations to a thickness of ¼ inch. The laminations and non-metallic spool heads effectively prevent eddy current losses and assist in raising the receiving efficiency. The pole pieces are placed so that a maximum number of lines of force pass through the diaphragm. The windings are impregnated with high-grade armature varnish and baked to render them moisture-proof. The diaphragm is held securely in a true plane by the broad diaphragm bearing surface and by the ear cap which clamps the diaphragm evenly and at the centre of the bearing surface. " It is this attention to detail and quality of manufacture that gave SC its reputation.



Although their intention was to build a better telephone, Stromberg Carlson still had to resort to novel ways around the outstanding telephone patents. One such was the switchhook. Their early wall phones resorted to a rather clumsy but effective method consisting of a bar across the front of the phone, with a receiver fork at one end and a lever at the other. To make a call the user lifted the receiver and turned the lever 90 degrees to rotate the transmitter into position. Switches connected to the arm completed the circuit. Once the patent expired they returned to a more standard switchhook design.



In about 1899 they designed a combined coil, switchhook, transmitter and arm assembly called a Triplet. This combined most of the electronics into a single unit, and proved very popular. It was particularly popular with repair companies, who could now upgrade most of the electronics in the older twin box and three box wall phones with one unit.






Stromberg Carlson's phones generally followed the standard patterns of the time. Initially they used the big twin box wallphones. Their top box was somewhat bigger than many of their competitors', due to the large magnets used in the bigger generators for long rural lines. The generator was another example of their quality construction - big, heavy, very solid. The early versions had a cast sideplate with the company name on it. I have one of these that still puts out a very healthy voltage, even though it is close to a hundred years old.

Note the triplet unit.

The larger battery box models allowed extra batteries to be used for long lines. Such phones were generally known as "long distance phones".






Left: The triplet was also used to build this attractive little wall phone, which dates from around 1902.

Right: An early long-box CB model







Left: SC 5-magnet generator. Note the "dogleg" crank, marking this as an early model.



When Western Electric released their single box Model 317, Stromberg Carlson followed suit in 1907 with their equivalent Model 101, as did most other manufacturers. These phones were fairly similar to the WE model, with a Cathedral Top and Picture Frame Front, but tended to be a little taller to allow for the bigger generator. The enclosed receiver as shown above was also introduced on some of these models. The Australian Post Office made large purchases of these phones, SC No. 896, from 1918. Like the WE phone, the picture frame front and cathedral top were soon omitted. The carbon block lightning arrestor was moved from the top of the case to the side.










Left: Model 101 with OST receiver, external lightning arrestor, cathedral top and PF front and long arm transmitter.

Right: Model 896 with simplified case, short arm transmitter and later enclosed receiver. Photo courtesy K & S Alexander

This phone is an interesting very early version of the model. It has a dogleg crank and single-strand internal wiring. Both were quickly dropped as stock ran out in favor of a straight crank and multi-stranded wiring.


Left: Internal view of the Model 896, showing the later painted generator. Note that the wiring is no longer soldered to the case hinges. Later phones often included a condenser (above the generator) so they could be converted to CB if needed. Photo courtesy K & S Alexander.



























Above: internal layout of the Model 896


From the early days party lines (called Bridging telephones) were an important part of telephony worldwide. The capital cost of providing lines could be offset by sharing each line between a number of users, and with comparatively low telephone usage this did not cause congestion problems. Stromberg Carlson had a number of party line wiring arrangements available for its customers. Their telephones were usually fitted with a condenser so if a receiver was left off-hook, the rest of the part line would still have service. The condenser provided continuity through the phone. The following information is from a 1920 manual for the Model 896 wall phone.

Regular Bridging with Non-interfering Pushbutton: this allowed a party to ring the central office without ringing all other bells on the party line. One leg of the line was sunted to earth when the button was held in while ringing.

Divided ringing: half the bells on a party line were shunted to earth on one leg of the line, and the rest were shunted to earth on the other line. Only half the bells rang at a time, halving the number of code rings heard at a telephone.

Harmonic 4-Party ringing: Each of four parties had the ringer in their phone tuned to a particular frequency. A special "pulsating" ringer generated the appropriate frequency at the central office. By using one, two or three rings, up to 12 parties could be connected on this system.

Harmonic 8-Party ringing: a combination of the previous two methods.

Synchromonic 4-party signalling: similar to Harmonic ringing, with mechanically-generated ringer pulses at the central office.

Biased ringer 2- and 4-party signalling: bells polarized to ring on one or the other leg of the line. The central office generated the appropriate polarized ring.

There was also a group of ringer systems using the Leich ringer frequencies.

The 896 magneto wall phone could also be converted to CB as exchanges were upgraded. The battery could be left in circuit to provide transmitter current on very long lines.


In 1899 Stromberg Carlson won the contract to supply telephones and equipment to the Home Telephone Company in Rochester. The HTC was so impressed by the quality of the telephones that they bought out the company in 1904 to ensure supply. The Chicago works was moved to Rochester to a newer, larger factory. The new factory employed 1200 people. Their range included phones, switchboards and cable as well as many general electrical items.

A popular style of early desk phone was the candlestick. Stromberg Carlson experimented with some very crude types with fixed, upright transmitters, but by the late 1890s they were ready to release their first mass production models.



Left: the 1897 "Roman Column" model, a classic early model with an Ericsson transmitter

Right: the 1900 "Oilcan" candlestick.







By around 1905 a less ornate but more functional design was introduced, sometimes called the "Kansas City " model. It was somewhat similar to the equivalent Western Electric model with a straight-sided shaft, but was better finished with nickelled trim. The transmitter adjustment was still the older twin post and locknut variety (below right) , but around 1908 a new top was introduced that featured a ball-joint type adjustment (see below). The new phone was a little shorter than the Western Electric.

During World War 1 domestic production was suspended and Stromberg Carlson became a major supplier to the U.S. Army Signal Corps. During the war Stromberg Carlson also absorbed the Dean and American Electric companies.










Post-War, Stromberg Carlson resumed telephone manufacture. In 1920 - 1021 they released their No. 986 candlestick phone (above left). It had the ball-joint adjustment for the new transmitter and a raised base to accommodate a dial, It still featured some nickel trim that made it look a little better-finished than similar phones of the time. A Stromberg Carlson dial version was not initially available, but it was designed to be fitted with dials made by Automatic Electric, Kellogg, or Western Electric according to the preference of the buyer.


Left: With the increasing preference for handsets, Stromberg Carlson recycled the old triplet unit into the Model 1190.






Left: No 1177

Right: No 1178











They moved into the new bakelite handset telephones with their 1936 No. 1212, called the "fat boy" (above , left), and its predecessors , the 11x8 auto and 11x7 CB phones. Note that the model number varied according to the type of dial, bell impedance, etc. A little wooden wallset (similar to the Australian Post Office Type 37) was released as a stopgap measure until bakelite wall phones went into production. In wood and later steel, this phone was widely exported. It was used in Australia by the Australian Post Office and some of the State Railways. It proved a good telephone for areas where rough handling could be expected such as Public Telephones.


Stromberg Carlson widened its range of products in the 1920s to include new technology such as radio sets. They are as well known for these as for their telephones. In 1930 sales of radios passed sales of phones. SC opened a plant at Alexandria in Sydney in 1927, and this was given almost entirely to radio production. This period marked a change in emphasis for SC, with most growth being in new areas and telephones dropping back.














Above Left: No 1211 wall phone

Above right: Auto equivalent


In 1940 a new table set was released, the No. 1222. It used a cast metal case that was very close to WE's No 302 telephone, but the Stromberg Carlson's cutoff corners were distinctive.

During World War 2, Stromberg Carlson again turned to military production. The U.S. Navy became a major client.















In 1946 SC redeveloped the No 1222 with updated electronics into the No 1223. A wall phone version was also made available. In the revised circuit a cleverly designed coil could be tapped off at two different points to provide an anti-sidetone circuit for CB or magneto use. A magneto was housed separately as required, or could be added to the base to form a rather bulky and unattractive phone. Apart from this, most phones from the big three makers - SC, Kellogg and WE - were staring to look more and more like each other.




No 1243 auto desk phone from 1940, in ivory and black.





During the Second World War. Stromberg Carlson again switched over to military communications equipment. This is a magneto-signalling naval phone.







No 1543, an early 1950s update to the 1243 phone to give it a more modern appearance.It was designed to make the phone similar to WE's new 500 phone. It still retained the Stromberg Carlson corner cutoffs. Other companies, including WE, performed similar updates to their earlier models for the same reason. The phone could also be modified with special switchhook and plunger to convert it to wall mounting.




This was, for all practical purposes, the last SC phone. Following Govenment pressure and a court case against Western Electric and AT&T, the WE 500 design was made available for other firms to build under license. SC took up the license and gradually dropped out of telephones. The only difference between these 500-type phones is the maker's brand moulded into the case behind the switchhook.



Left: Model 1553 wall phone, basically the same as the Western Electric design






After the War they developed into the new digital switching systems, and brought out their XY system ( a version of an Ericsson flat switch) in the 1960s. This followed a merger with General Dynamics in 1955. General Dynamics was a major maker of electronic components at their factory at Charlottesville, and all SC's manufacturing was moved here also. The XY system was designed here. It was used to build electronic switching PABXs initially, and during the 1970s they built it into digital exchanges. This effectively marked the end of Stromberg Carlson as a provider to the independent phone companies. At this point Western Electric was making its own phones available for license. SC made these for a while, then eventually dropped out of telephones altogether.

In 1982 the Charlottesville factory was bought by Comdial

To Telephone Companies

If you have reached this page through a Search Engine, this will take you to the front page of the website