Operational magneto service
Early telephone service was often magneto service with party lines. Magneto is an electrical device that generates electric current by moving a coil past a magnet. When we speak of magneto telephones, we are talking about telephones with hand-cranked generators. You turn the generator to ring the bell. You’ve probably seen magneto telephones in old movies. We have several of them right here in our museum. These telephones are quite large compared to modern telephones. In addition to the hand-cranked generator, there were also two large dry-cell batteries inside the telephone—these provided the three volts of direct current to power the talk circuit. Local batteries were required because, unlike central offices in large cities, small telephone offices in remote areas did not supply power to operate subscriber’s telephones.
Let’s talk about party lines for a moment. (And, again, you can read the How Phones Work
article in our Science of Phones section for more general information about this, switchboards, ringers, etc.) With a party line, as many as 20 homes could share the same telephone line. This was done to minimize the number of telephone wires that had to be installed (and maintained) in remote areas.
Don’t forget that even though you may have shared a party line with your neighbors, you still had your own telephone number assigned to your telephone. But each time a call came through all telephones on the party line would ring at the same time. You had to listen to the ringing sequence to determine to whom the call was intended. For example, your home phone number might correspond to four short rings and your neighbor’s to two short rings followed by a long ring. Good neighbors did not spend much time on the telephone since so many others shared the same line.
To place a telephone call, you would first “crank up” the call. If the called party was on your line, you simply cranked the magneto in your phone with the distinctive ring to alert the appropriate party—for example, two short rings and a long ring for your next-door neighbor. Since all telephones on the same party line would ring, it was important to listen carefully to the ring sequence before answering the phone.
Calls to telephones outside your own party line required the assistance of a switchboard operator. Later, as telephone equipment became more advanced, other ringing methods were introduced for party lines. These included selective ringing using harmonic ringers, biased ringing, and three-wire ringing. For examples of selective ringing, click here
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