Rotary dial phones are the earliest user controlled phone to be mass produced. Prior to the rotary phone a user would pick up the phone, wait for the operator to answer and then tell the operator who they wanted to be connected with. With the rotary dial, the user was able to dial freely, allowing for quicker and more convenient connection to the people they wanted to speak with.
Before Rotary Phones
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In 1878 the first telephone exchange was installed in New Haven, Connecticut. This system required an operator to connect the lines by using patch cables. The user, picking up the phone, would light a signal lamp on the operators panel. The operator would answer and "patch" the caller through to the other end. This system was cumbersome, but existed in some form for decades. During World War II, the military had priority use for phone systems. This slowed civilian traffic and a cross-country call could take as long as 2 hours to connect if manual connection was needed.
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First Rotary Phones
Starting in 1879, 26 patents were filed for various dials and buttons which were either too expensive or cumbersome to use. The first use of a dial phone was in 1892 in La Porte, Indiana based on a 1891 patent by Almon Brown Strowger. In 1919 the American Bell Telephone Company began national service for user controlled rotary dial phones.
Specifications
The standard form of the rotary dial is a disk three inches in diameter with 10 holes, numbered in one of four forms 1-9 then 0, 0-9, 9-0 or 0 then 9-1. Despite the different numberings, when the first number was dialed, 1 pulse was sent and when the last number was dialed, 10 pulses. This meant that each phone on a system had to have the same dial and phones could not be easily interchanged into other systems. The 1-9 then 0 form was eventually standardized.
Use Over Time
After the invention of the phone, an operator had to be contacted in order to place a phone call. In 1892 Strowger set up an exchange with a capacity of 99 phones in his home town of La Porte, Indiana. He started with 75 subscribers. Strowger sold his patent in 1896 for $1,800 and it was again sold for $2.5 million in 1916 to the American Bell Telephone Company who started service using these phones.
Phasing Out Rotary Dial
Until the 1970's, when push button tone dial was introduced, rotary phones were the only viable option for user controlled phones. By the 1980's most rotary phones were phased out. In many areas it is now an added feature to have rotary service.