Asterisk and Me

A telephony love story

(All about . . . . )

Brian Capouch

brianc@palaver.net

http://slides.com/capouch/astricon/live

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?

github.com/capouch/asterisk-graphql.git

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

• api-spec-converter
• swagger-to-graphql
• APIMATIC
• Manual conversion

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?

The "classic" telephone set

• 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

asterisk-speech-recog

;;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()