Category Archives: Telephone history

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.



Hugo Gernsback’s Vision of the Telephot, 1918

1918MayElecExpCoverShown here on the cover of Electrical Experimenter a hundred years ago this month, May 1918, is Hugo Gernsback‘s vision of Skype, or what he called “telephot, an apparatus attachable to our present telephone system so that when we speak to our distant friend, we may see his likeness not only as an immovable picture, but we will see his image exactly as we see our own image when looking into a mirror. In other words, the apparatus must faithfully follow every movement of our distant friend whether he is only five blocks away or one thousand miles. That such an invention is urgently required is needless to say. Everybody would wish to have such an instrument, and it is safe to say that such a device would revolutionize our present mode of living, just as much as the telephone revolutionized our former standard of living.”

Gernsback reported that inventors were working on the problem, but the main catch was what we would today call the bandwidth, since it had to be “possible to attach it to the present-day telephone lines,” which to him was a single wire and a ground return wire. “In most of the schemes offered by inventors heretofore, a plurality of wires was necessary; in some cases several thousand pairs of wires. No matter how well such an instrument might work, this alone would doom it to certain failure.”



Listening In On Enemy Trenches: 1918

1918MayElecExpThis diagram appeared a hundred years ago this month in the May 1918 issue of Electrical Experimenter, and explains why users of field telephones in the trenches had to maintain security in their communications, even though there was no possibility that the line was tapped.

The diagram shows the Germans listening in on the Americans’ telephones, but it could just as easily be the other way around. By running a line parallel to the other side’s line, it was possible to pick up the conversation inductively. A powerful amplifier might be used, but in many cases, it was possible to listen in with an ordinary telephone receiver hooked to both ends of the line.



Mamas, Don’t Let Your Babies…

1918MayPS

…grow up to be–er, I mean, suck on telephone cords.

As a public service announcement, we bring you this reminder, which originally appeared in Popular Science a hundred years ago this month, May 1918.

There was apparently at that time a veritable epidemic of babies sucking on phone cords. According to the magazine, a woman called the complaint office of the phone company to report a malfunction in her instrument.  The phone company employee, who had apparently heard it all, immediately suggested that the customer check the cord of her phone to see if there was a dark and wet spot.

The customer confirmed that it was wet, and indignintaly replied, “baby was playing with the cord this morning and took it in her mouth, sucking at it for a while. Surely there can be no harm and that.”

The complaint clerk, according to the magazine, “had heard the same story many times,” callously told the woman to have the baby knock it off.

Insulation quality is probably better these days. But still, you shouldn’t let your baby suck on any kind of electrical cord. And if someone suggests otherwise, please don’t indignantly tell them that there’s nothing wrong with it.



1918 Train Dispatching

1918AprElectricalExpA century ago, with much of the labor force off to war, American industry turned to women to fill many jobs traditionally held by their male counterparts. Shown here is one of the hundreds of young women being trained to be train dispatchers. The article, in the April 1918 issue of Electrical Experimenter, pointed out that the job was exacting, and in the real world, mistakes could easily mean death or dismemberment. Therefore, the women were trained on the model railroad shown here, before being unleashed on the real rails. The dispatcher would set signals and switches, with the model trains responding.