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To: vpintheak

Rotaries are digital.

Touch-Tones were analog.


48 posted on 07/07/2024 5:54:59 PM PDT by Paladin2 (Get off my phone, you big dope.)
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To: Paladin2
Rotaries are digital.

Touch-Tones were analog.

That is very misleading.   Rotary phones sent a sequence of electrical pulses to the CO switch either, crossbar or step-by-step.   Both switching systems existed over a century ago, long before digital computers were created.

Touch Tones or DTMF (Dual Tone Multiple Frequency) telephone signaling was planned to be used on the old analog crossbar or step-by-step switches, but were used in the transition into digital frontend telephone switches like the 1ESS (Number One Electronic Switching System) and all the electronic switches that followed.

Each tone of a touch phone key was a combination of two frequencies together.

                        DTMF Frequencies

       1209 Hz  1336 Hz  1477 Hz  1633 Hz  
697 Hz     123A
770 Hz     456B
852 Hz     789C
941 Hz     *0#D

If you pressed the number one, the dual tone of 1209 Hz and 697 Hz was sent to the Central Office and is detected by the switch.

Since analog switching goes back 125 years and rotary phones used electrical pulses like an old fashioned telegraph key, they are considered analog technology and the DTMF phones are considered digital because they more connected to the modern digital world.


84 posted on 07/07/2024 8:48:51 PM PDT by higgmeister (In the Shadow of The Big Chicken! )
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To: Paladin2

Ok... From Brave search engine.
Were rotary phones digital?
Rotary phones, also known as rotary dial phones, were not digital in the modern sense. They used an analog system to transmit phone numbers. Here’s how it worked:

The rotary dial had a mechanical mechanism that converted the rotation of the dial into electrical pulses.
Each number on the dial was connected to a specific electrical circuit, which generated a unique pulse pattern when the dial was rotated.
The pulse pattern was transmitted over the phone line to the telephone exchange, where it was decoded and used to connect the call.
The pulse pattern was not a digital signal in the classical sense, as it was not a series of discrete 0s and 1s. Instead, it was an analog signal that represented the sequence of numbers dialed.

In contrast, modern digital phones use a digital signal to transmit phone numbers, which is a series of 0s and 1s that represent the digits of the phone number. This allows for more efficient and reliable transmission of phone numbers, as well as the ability to transmit additional information such as text messages and data.


92 posted on 07/07/2024 10:59:27 PM PDT by vpintheak (Sometimes you’re the windshield, sometimes you’re the bug. )
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