Eli5: How do automated services on phones know what buttons you’re pressing?

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I was just refilling a prescription on the automated line and the thought just dawned on me. How do they know what buttons I’m pressing? Sorry if this is really dumb. I understand next to nothing about technology. Thanks

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18 Answers

Anonymous 0 Comments

Each button sends a different, unique tone to the other tone. Both phones know which tone each number sends.

Anonymous 0 Comments

You know those beeps that happen each time you hit a button? Those are [DTMF tones](https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling), and they can be decoded on the other side. The frequencies of each beep correspond to a number.

That system has been in place since touch-tone dialing was a thing.

Anonymous 0 Comments

Each button sends a different, unique tone to the other tone. Both phones know which tone each number sends.

Anonymous 0 Comments

Each button press initiates a tone which is sent and recognized by the receiving party.

It’s actually a combination of 2 tones in harmony. 2 sets of 4 tones. Meaning there are a total of 16 different combinations. You have access to 12 (0 1 2 3 4 5 6 7 8 9 # *) and there are 4 ‘hidden’ ones (A B C D) that the phone company can use for special system access, diagnostics, and whatnot.

For more information, the system is called Touch Tone

Anonymous 0 Comments

Basically the same way that when you hear music being played on the radio, you hear all the different sounds.

Each button has a different sound. You can think of them as notes on a piano.

1 – A

2 – B

3 – C

4 – D

etc.

So then when you are on the call, and lets say you type in your prescription number, your phone transmits those tones (called DTMF) and the other side hears it, and converts it back to the numbers they meant. Then looks up the prescription.

Nowadays with newer technology and digital everything the tones don’t even need to be sent all the time. But that’s how the older technology worked.

Anonymous 0 Comments

Basically the same way that when you hear music being played on the radio, you hear all the different sounds.

Each button has a different sound. You can think of them as notes on a piano.

1 – A

2 – B

3 – C

4 – D

etc.

So then when you are on the call, and lets say you type in your prescription number, your phone transmits those tones (called DTMF) and the other side hears it, and converts it back to the numbers they meant. Then looks up the prescription.

Nowadays with newer technology and digital everything the tones don’t even need to be sent all the time. But that’s how the older technology worked.

Anonymous 0 Comments

You know those beeps that happen each time you hit a button? Those are [DTMF tones](https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling), and they can be decoded on the other side. The frequencies of each beep correspond to a number.

That system has been in place since touch-tone dialing was a thing.

Anonymous 0 Comments

Each button press initiates a tone which is sent and recognized by the receiving party.

It’s actually a combination of 2 tones in harmony. 2 sets of 4 tones. Meaning there are a total of 16 different combinations. You have access to 12 (0 1 2 3 4 5 6 7 8 9 # *) and there are 4 ‘hidden’ ones (A B C D) that the phone company can use for special system access, diagnostics, and whatnot.

For more information, the system is called Touch Tone

Anonymous 0 Comments

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Anonymous 0 Comments

Each button sends a different, unique tone to the other tone. Both phones know which tone each number sends.