IVR

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Contents

Definition

Interactive Voice Response (IVR) is an automated telephony system that interacts with callers, gathers information and routes calls to the appropriate recipient.

Please note that if you are speaking to someone with a traditional telephony background, a simple call routing menu is called an Automated Attendant. The term IVR is reserved in the telecom industry to refer to a more complex system that relies on some sort of back end application. A self-contained menu that does nothing more than route calls to destinations would not be considered an IVR. FreeSWITCH and other open source telecom apps are cool because even the most basic menu could be argued to meet the definition of an IVR, but generally the term "Automated Attendant" is preferred in the telecom industry unless something more than rudimentary call routing is involved. Telecom people dream of the day when Emerging Telecom and VoIP professionals start to understand the difference between an IVR and an Automated Attendant, and use the terms correctly. (In telecom, people who refer to an Automated Attendant as "The IVR" are instantly considered newbies). Until the day everyone uses the terms correctly (or one side gives up), be aware of who you are talking to, or there will be confusion when you are scoping out a project.

Language

FreeSWITCH IVRs can be written in any language that FreeSWITCH supports including JavaScript, Python, Perl, Lua and an XML macro format.

Sample IVRs

Included in Source

demo-ivr.xml

A sample IVR written in XML is included in the source. The IVR menus are loaded from conf/autoload_configs/ivr.conf.xml

The dialplan entry that calls the IVR menu is:

   <extension name="ivr_demo">
     <condition field="destination_number" expression="5000">
       <action application="ivr" data="demo_ivr"/>
     </condition>
   </extension>

The macro file for the IVR is located at conf/lang/en/demo/demo-ivr.xml.

Lua IVRs

Hello World

-- answer the call
session:answer();

-- play a file
session:streamFile("/path/to/blah.wav");

-- hangup
session:hangup();

Play Menu and get digits

digits = session:playAndGetDigits(1, 3, 3, 3000, "#", "/menu-greeting.wav", "/invalid.wav", "\\d+")
session:consoleLog("info", "Got dtmf: ".. digits .."\n");  

Read Digits

digits = '12345';
-- the next line will say "one two three four five"
session:execute("say","en name_spelled pronounced " .. digits);
-- the next line will say "twelve thousand, three hundred forty-five"
session:execute("say","en number pronounced " .. digits); 

db_agent_login

Example PostgreSQL-backed Lua IVR

directory lua

  • answers call
  • plays file asking for input of 1st 3 chars of last name
  • looks in list for matches
  • if match found play recorded_name if available
  • otherwise spell out name and extension
  • ask for confirmation of match
  • if not the right one play the next one
  • if confirmed transfer to extension
  • otherwise play no match found and restart directory ivr

directory.lua

directory in lua using ASR and TTS

directory_asr.lua

inbound conferencing using lua

simple_conference.lua

Example of a "group confirm" alternative: speaks text and does not require the call to be accepted

Here's an example where you can use Lua to speak some text (using TTS), or playback a file, or do whatever you want without requiring a group confirm key!

To achieve this, we want to use the exec functionality of group_confirm_key to call a Lua script with the selected menu option so we know what text to speak. The following script would be the frontend "automated attendant" Lua script:

selection = session:playAndGetDigits( 1, 1, 1, 3000, "#", "main-menu.wav", "", "" )
if( selection ) then
   session:setAutoHangup(false)
   session:execute( "set", "group_confirm_key=exec" )
   session:execute( "set", "group_confirm_file=lua lua/speak_selection.lua " .. tonumber(selection) )
   session:transfer( "10", "XML", "extensions" )
end

As you can see, we are calling speak_selection.lua with 1 argument: tonumber(selection) (ie. the digit the caller pressed from the main menu). The content of speak_selection.lua is:

options = { "sales", "technical support", "whatever text you want to read out for menu option 3" }
session:execute( "speak", "flite|kal|" .. options[tonumber(argv[1])] )

This was mostly for "playing" purposes, but if you happen to share an extension where different types of calls may come in (sales, tech support, etc) this system helps as it announces which menu option the caller entered.

Checking if a user exists & if they're registered before dialing

This is used, for example, in a menu where you allow the caller to enter an extension. Rather than blindly dialing their extension, you could check if the user exists first and if they do, check if they're registered before finally attempting to dial. This is my way of doing it. If you have a different way of doing it .. add to the page!

-- * = go back to the main menu
-- <blank> = timeout after 3 tries
local extension = session:playAndGetDigits( 1, 2, 3, 3000, "#", "ivr/ivr-enter_ext.wav", "ivr/ivr-that_was_an_invalid_entry.wav", "[\\d{2}|*]" )
if( extension ~= "*" and extension ~= "" ) then
   session:execute( "set", "contact_exists=${user_exists(id " .. extension .. " ${domain})}" )
   if( session:getVariable( "contact_exists" ) == "false" ) then
       session:execute( "playback", "voicemail/vm-that_was_an_invalid_ext.wav" )
   else
       session:execute( "set", "contact_available=${sofia_contact(internal/" .. extension .. "@${domain})}" )
       contact_available = session:getVariable( "contact_available" )
       if( string.find( contact_available, "error" ) ) then
           session:execute( "speak", "flite|kal|the extension number " .. extension .. " is not available" )
       else
           session:execute( "playback", "ivr/ivr-hold_connect_call.wav" )
           session:execute( "set", "transfer_ringback=${hold_music}" )
           session:transfer( extension, "XML", "extensions" )
       end
   end
end

Javascript IVRs

See also: The Javascript Examples page.

dbivrmenu js

This IVR uses an sqlite database for storing the menu options. The database creation script is here - Examples dbivrmenu dbcreate js. The IVR script is here - Examples dbivrmenu js.

afterhours ivr

This is a basic javascript ivr that plays the message once and transfers to the voicemail extension of the operator at the end if no input is given. The IVR script is here - JavaScript Example afterhoursivr.js.

Python IVRs

See Mod_python for more info on how to get these working.

frontdoor py

  • Plays welcome message
  • During welcome message play, press "0" to get special options (sneak in the backdoor)
  • If nothing pressed, continues
  • If "after hours", makes users press an extra key to continue
  • Bridges to destination endpoint(s) (eg, your phones)

The IVR script is here - Examples frontdoor py.

basic voicemail

Uses Django O/R layer to talk to a database and save/retrieve voicemails:

voicemail.py

directory py

  • answers call
  • plays file asking for input of 1st 3 chars of last name
  • looks in list for matches
  • if match found play recorded_name if available
  • otherwise spell out name and extension
  • ask for confirmation of match
  • if not the right one play the next one
  • if confirmed transfer to extension
  • otherwise play no match found and restart directory ivr

directory.py

See also