TeleSignals Demo

A light weight library that plays standard famous telephone signals without binary sound files, using Web Audio API.

Installation

npm i @phonelift/telesignals

Usage

import teleSignalsInit from '@phonelift/telesignals'
// Or find it in window.teleSignalsInit if you use the UMD format file.

const teleSignals = teleSignalsInit()

// Attach listeners to all buttons. When a button is clicked, read its content and pass it to playDTMF()
// Check the file /static/index.html for the HTML
document.querySelectorAll('#keypad button')
  .forEach(button => {
    button.addEventListener('click', function (event) {
      teleSignals.playDTMF(event.target.innerHTML)
    })
  })

window.addEventListener('keydown', function (event) {
  teleSignals.playDTMF(event.key)
})

// More examples in /static/dev.js

teleSignalsInit(audioCtx = null)

The only function that is exported by the module.

It tales one argument of the type AudioContext. If you don't provide any, it will create its own internal instance of AudioContext.

From the Web Audio API specification proposal:

In most use cases, only a single AudioContext is used per document.

So, if your app already has one, then it's a good idea to pass it to this function.

teleSignalsInit returns an object that has three functions:

| Function | | ------ | | playDTMF(key: string) | | play(key: string) | | stop() |

playDTMF(key: string)

Plays a DTMF tone. key can possibly be one of the following values: 0-9, A-D, # and *. Any other values will be ignored.

play(key: string)

Plays one of the pre-defined signals. key can possibly be one of the following values:

• busy to play Busy signal
• ringing_tone to play Ringing tone
• recorder to play Reorder tone
• disconnect to play Disconnect tone

Calling one of these while the other is playing will stop the previous one and initiate the new one.

stop()

Stops playing one of the predefined signals that are started by play(key: string). This doesn't affect DTMF tones initiated by playDTMF(key: string).

Browser Compatibility

This library makes use of the Web Audio API, therefore it has the same browser support.

Issues and Bugs

Please submit your requests or report issues and bugs here.

Contribution

Feel free to discuss any addition or improvement before you submit a merge request. Please don't commit anything in the dist folder. This folder gets updated just before a release.

License

MIT