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DTMF

DTMF, short for 'Dual Tone Multi Frequency' is a technique that was used in analog telefony to transmit information over telephone lines between telephone equipment and other communications devices and switching centers.

Lookup table

1209 Hz 1336 Hz 1477 Hz 1633 Hz
697 Hz 1 2 3 A
770 Hz 4 5 6 B
852 Hz 7 8 9 C
942 Hz * 0 # D

Cipher behavior information

  • Case sensitive? ❌
  • Deterministic? ✓
  • Alphabet: 01234567890*#ABCD
  • Characters not in alphabet will be: omitted or throwing an error (default)

Default options object

The options are the same for both methods, encode and decode

const options = {
  mode: 'include', // Can be include, sum or diff
  connector: '+',  // The character between two frequencies (in include mode)
  separator: ' ',  // The character seperating encoded characters
  invertedOutput: false, // Should frequencies be inverted (in include mode)
  failOnUnknownCharacter: true // Should an error be thrown when a character can't get en-/decoded
}

Usage

Encoding

Default (include mode)

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123')) // 697+1209 697+1336 697+1477

Inverted output

The invertedOutput option is only relevant when you are in the include mode (default).

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123', { invertedOutput: true })) // 1209+697 1336+697 1477+697

Custom connector

The connector option is only relevant when you are in the include mode (default).

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123', { connector: '#' })) // 697#1209 697#1336 697#1477

Sum mode

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123', { mode: 'sum' })) // 1906 2033 2174

Diff mode

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123', { mode: 'diff' })) // 512 639 780

Custom separator

import { dmtf } from 'cipher-collection'


console.log(dmtf.encode('123', { separator: '#' })) // 697+1209#697+1336#697+1477

Decoding

Default (include mode)

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('697+1209 697+1336 697+1477')) // 123

Inverted output

The invertedOutput option is only relevant when you are in the include mode (default).

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('1209+697 1336+697 1477+697', { invertedOutput: true })) // 123

Custom connector

The connector option is only relevant when you are in the include mode (default).

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('697#1209 697#1336 697#1477', { connector: '#' })) // 123

Sum mode

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('1906 2033 2174', { mode: 'sum' })) // 123

Diff mode

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('512 639 780', { mode: 'diff' })) // 123

Custom separator

import { dmtf } from 'cipher-collection'


console.log(dmtf.decode('697+1209#697+1336#697+1477', { separator: '#' })) // 123