Category Archives: Telephone history

1920 Robbins Telephone

1920AprilBLA hundred years ago, the Scout or “any Real Boy” desiring to set up his own private telephone exchange couldn’t go wrong with these telephone sets from the Robbins Manufacturing Company, 1807 North Central Park Avenue, Chicago. For $2, the company would supply two transmitters, two receivers, and a hundred feet of wire. The sets would work over a much longer distance with ordinary bell wire.

For Real Boys desiring a deluxe setup, two wall phones (suitable for grown ups, too) and 300 feet of wire were available for only $6.

The ad ran a hundred years ago this month in the April 1920 issue of Boys’ Life.



1935 Light Beam Communicator

1935MarPM85 years ago this month, the March 1935 issue Popular Mechanics showed how to make this light communicator, said to have a range of about a half mile.

The receiver used a caesium photo cell, which the magazine said could be had for about $3. This was fed into a two-tube amplifier which could drive a speaker or headphone.

For audio amplification at the transmitter end, the system used the household radio receiver, and the magazine explained how to hook up the microphone. The the light beam generator used a system I’ve never seen before. Instead of electrically modulating the light bulb, a mechanical approach was used. The speaker was disconnected and the output was instead connected to a magnetic headphone that had been modified. The outer cap of the headphone was unscrewed and cut so that most of the metal diaphragm was visible. Then, the “diaphragm is slipped off and taken to any plating firm to be finished in the same manner as an audio headlight reflector.” The headphone was reassembled, and the result was a mirror that would vibrate in time with the sound. An auto headlamp was used to illuminate the mirror, and this was focused through a lens with a focal length of about 12 inches.

The result would have been a narrow beam of light that was modulated. At the receiving end, another lens was used to focus the beam on the photo cell.

For a unique science fair project, the advanced student could adapt this project using modern materials.  When I was a kid, I built a similar system using a flashlight as the transmitter.  The bulb was wired in series with the secondary of an audio transformer.  The primary was fed by the output of an amplifier.

For the receiver, I used a solar cell fed directly to the input of an audio amplifier.

1935MarPM2



1920 Telephone Set

1920JanBLA hundred years ago this month, the January 1920 issue of Boys’ Life magazine carried this ad for a real telephone for real boys. The set came with two transmitters, two receivers, and 150 feet of wire, all for $2. The ad noted that for longer distances, bell wire could be used. The set was available from dealers, or directly from the Robbins Manufacturing Company, 1807 N. Central Park Avenue, Chicago. It was billed as just the thing for scout work.



Avoiding Telephone Annoyance, 1920

1920Jan19EveningLedgerFor those who are annoyed by noise while talking on the phone, then this device from a century ago would prove helpful. As shown, the earpiece covers both ears, ensuring that your call won’t be interrupted.

The picture appeared in the Philadelphia Evening Public Ledger a hundred years ago today, January 19, 1920.



1919 Forest Service Heliograph

1919NovElecExpOne hundred years ago, the forest ranger shown here is acting as “lookout man” atop some Western peak. As he watches for forest fires, he has at his disposal detailed maps of the area, as well as two means of communication. When he spots a fire, he can call in the bearing to headquarters on the telephone. To communicate with other spotters in areas too remote for a phone, he has the heliograph. On clear sunny days, the device had a range of up to 45 miles.

The first Forest Service heliograph units had originated with the Army Signal Corps, but more compact units suited to forest fire fighting were procured. Seven rangers were initially trained. Even though they had no prior knowledge, they became proficient operators in a very short time.

While Morse Code could be used, it was found that the Myer Code, shown below, was more reliable for visual signaling. The letter P, for example, is 1211. The one indicates a long flash, and the 2 indicates two short flashes.

MyerCode

The top photo appeared in the November 1919 issue of Electrical Experimenter. More details of the system can be found in a 1914 Forest Service Publication, Systematic Fire Protection in the California Forests.  The heliograph instrument consisted of a mirror, which was oriented so that it reflected the sun on the receiving station. A shutter in front of the mirror was used to key the beam on and off. To call another station, the sending station would send a quick succession of flashes until acknowledged. Then, each station would turn on a steady flash to make adjustments. When the mirrors were in place, the sending station would proceed with its message. The average speed of transmission was found to be about four words per minute.

Plans for a simple heliograph can be found at an earlier post.

 



1959 Radio/Intercom

1959RadioTVExp3Sixty years ago, the occasional publication Radio-TV Experimenter carried this interesting project. As the enclosure, it used an already antique crank-type wall telephone as the housing for a radio receiver, but put the telephone back into service as a home intercom.

According to the magazine, the phone was rapidly vanishing from the American scene, and interior decorators had been busy snatching them up to convert into spice cabinets, pin-up lamps, and liqueur chests. Instead, the magazine showed how to preserve the original communication function by providing an intercom between floors of a house, between house and garage, etc.

The radio function was added by use of something found in almost every home, “a small table-model radio set of the ac-dc type that has been set aside because of a broken cabinet, missing knob, or a minor circuit defect.” Such a radio was squeezed in, with the controls mounted under the phone’s writing desk.

Obtaining the phone was a matter of ordering one from Telephone Repair & Supply Co. of 1760 W. Lunt Ave., Chicago, where it was available for $7 plus postage for the 20 pound instrument. Most such surplus phones came with the crank, but not the magneto, since apparently the phone companies still needed some of those for their rural customers.  The phone will have been in service for fifty years, so the article gave details on how to refinish the wood and metal components.

The article next explained how to wire the phone back up. Even without the magneto, the ringer could be made to work by including a button on the side of the phone (where the crank used to be), wired to the bell through an induction coil. Presumably, the phone would ding once when the button was depressed. A three wire circuit (or two wires plus ground) was used to hook the phones together, with one wire for the voice connection and one for the ringer. The wiring diagram is shown here:

1959RadioTVExp4

 



1959 Cubicles

1959AugRadioElecWhat are these people doing, and what does it have to do with Dutch footwear? And how does the guy in the center get in or out of his cubicle?

These people, from a Bell Labs ad in the August 1959 issue of Radio Electronics, are helping The Phone Company rate the effects of various kinds of noise and interference. The ad notes that noise is a major distraction to modern living, and “an enemy of the Bell System.” They did all they could to fight it, and that’s what these people were doing.

The gentleman in the center would play a tape with common phrases, such as “the native Hollander wears wooden shoes.” In carefully controlled tests, he would then introduce noise to the line, as well as playing background noise through a loudspeaker. These volunteers would then rate the quality of the call.

As to the last question, how the guy in the center got in and out, I’m not sure, because the ad doesn’t say. I assume it involved crawling underneath, because none of the cubicles appears to have a door. Interestingly, the office cubicle didn’t hit the market until 1967, so this was another case where Bell Labs was ahead of the times.



USFS Portable Phone, 1919

1919JulPSA hundred years ago, the U.S. Forest Service had the latest in portable telephones, as shown in the July 1919 issue of Popular Science.

This ranger is shown carrying the set, which weighs in at a featherweight 30 pounds. The bottom compartment contains the batteries, with the normal telephone transmitter and receiver in the top compartment. A magneto is included to ring the phone. Upon spotting a fire, the ranger races to the nearest phone line and hooks up the instrument. He gives the magneto a turn, which alerts the other phones on the line, and the fire gets reported.

But what if the other rangers have stepped out away from the phone? That’s where the middle shelf comes in. It contains a loud klaxon which would echo through the forest. If there’s no answer, the ranger switches the dynamo to DC to drive the klaxon and gives it another spin. The sound is presumably heard for miles around, his colleagues pick up the phone, and the fire gets reported.



Diozo Phone Disinfector, 1909

1909AprilPopularElectricityA hundred ten years ago this month, the April 1909 issue of Popular Electricity carried this ad for the Diozo Phone Disinfector, produced by the Parker Chemical Co. of 233 Market Street, Chicago.  (The address no longer exists, since Market Street disappeared and became part of Wacker Drive.)

The ad, confirmed by scientific tests, warns that the mouthpiece of every telephone swarms with malignant germs, including tuberculosis, diphtheria, typhoid, or pneumonia.  There might even be more revolting diseases lurking there!  Fortunately, to avoid the harm, all you need to do is slip the diozo phone disinfector on the mouthpiece.  Diozo is apparently a disinfectant that works in its solid form to somehow kill germs.

But according to this article published just a few months later in the California State Journal of Medicine, the State Hygenic Laboratory (of California, presumably) questioned some of the claims made by the company.  After being challenged, the company noted that to be effective, the Diozo must be crushed and mixed with water, which would make its use on a telephone somewhat problematic.

Strangely enough, the Diozo Phone Disinfector doesn’t appear to be available today.  But if you search Amazon for “phone disinfector,” you can chose among the following products:

 



1959 Auto Dialer

1959JanEESixty years ago this month, the January 1959 issue of Electronics Illustrated showed how to put together this convenient autodialer for a telephone. It was designed to be used with a burglar alarm or fire alarm, to place a call to a pre-designated number.

1959JanEE2The heart of the unit was the lever which went over the phone. In case of alarm, a solenoid released to let the phone off the hook. Then, the same lever was used to dial the phone by pushing the hook buttons. This was driven by the wheel shown here, which rotated thanks to a phonograph motor.

A bell or buzzer would sound over the phone, alerting the owner to the alarm.  The article did note that if the line was busy, the message would not go through.