Asterisk and Me

A telephony love story

(All about . . . . )

Brian Capouch

brianc@palaver.net

The plan:

  • Some things I've used Asterisk to do
  • Wrap an API in graphQL
  • Past and present meet next week

Yesterday: 3 Memories

1. Help save Medaryville's history

Challenges

  • At-risk historic structures in a dying town
  • Security a constant concern
  • No money!

cheap openWRT boxes (Netgear WGT-634U)

  • Routers/APs/Wifi client
  • Asterisk server - local and LD
  • Automation controller

2. Wide area "local" calling

Peoples Wireless "WATA"

  • Farmers' grain elevators (60-120')
  • 900 mi^2 redundant network
  • "eBay cheap" desktop at each site
    • Asterisk server
    • PCI FXO card (X100P)
    • "Co-op" dialplan

3. Teaching VoIP

Elective CS class in VoIP

  • Started offering 2002
  • Textbook a perennial problem
  • Evolution
    • Began with one shared server
    • Finish: local VM, "private cloud," cloud

Today: A little study

What would a graphQL view of the ARI API look like?

The browser is the future

  • Universal virtual application container
  • Modern functional JavaScript (ES6+)
  • "Write once; run everywhere"

REST v. graphQL

  • REST's weaknesses
    • API Discovery
    • Multiple fetches
    • Unused data/wasted bandwidth
  • graphQL uses "shared typed schema" approach

Tasks

  • Convert Swagger specs to graphql
  • Choose appropriate APIs to convert
  • Write graphQL wrapper atop ARI

What I tried

Which ARI APIs?

  • I wanted to demo both reads and writes
  • mailboxes didn't work!
  • Chosen for clarity and brevity:
    • sounds
    • endpoints

Demo Time #1

  • schemas
  • queries
  • mutations
  • resolver functions
  • The graphiQL UI

Tomorrow: Chasing a dream

MAG*NET

Using Asterisk with historic phone sets

How does a telephone work?

  • Talk Circuit (DC)
    • Receiver
    • Transmitter
    • Induction Coil
    • Battery

Signaling circuit (AC!)

  • Ringer assembly
  • Generator

What about signaling?

 . . a short digression

Medaryville Telephone Co.

  • 8 switchboards
  • About 100 telephone sets
  • Ringing and power equipment
  • Literature
  • Ephemera

Project goals

  • Unaltered phones
  • Classic call flows (i.e. w/o dials!!)
  • Multiple implementations of "operator" function
    • Old switchboards
    • Live remote human ("Mom")
    • ASR and Asterisk

Demo time #2

;;Simple speech recognition
exten  => 1234,1,Answer()
  same => n,Wait(1)
  same => n,Playback(nPlease)
  same => n(start),agi(speech-recog.agi,en-US,,,NOBEEP)
  same => n,Verbose(1,The text you just said is: ${utterance})
  same => n,Set(CALLED_PARTY=${STRREPLACE(utterance,"-","")})
  same => n,Playback(uEntered)
  same => n,SayDigits(${CALLED_PARTY})
  same => n,Verbose(1,And the parsed number is: ${CALLED_PARTY})
  same => n,Verbose(1,The probability to be right is: ${confidence})
  same => n,Playback(verifyNumber)
  same => n,agi(speech-recog.agi,en-US,,,NOBEEP)
  same => n,Verbose(1,The text in your command is: ${utterance})
  same => n,GoToIf($["${utterance}" = "yes"]?approved:test2)
  same => n(test2),GoToIf($["${utterance}" = "yeah"]?approved:retry)
  same => n(retry),Verbose(1,We need to try again)
  same => n,Playback(beep)
  same => n,GoTo(start)
  same => n(approved),Playback(uRconnecting)
  same => n,Dial(Motif/google/1${CALLED_PARTY}@voice.google.com,,r)
  same => n,Hangup()

Astricon

By capouch

Astricon

Keynote talk at Astricon 2017

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