Suppose I am given a task to design and implement an IVR for my company. So that if anyone will call to my company’s number, he/she will listen a greeting “Welcome to <company-name>” then he/she will hear options to reach the required department, like “To speak to our HR representative press 1 now”, “To speak to our Sales representative press 2 now”, “For accounts related queries press 3 now”, “To speak in our Administration Department press 4 now”, “For IT help desk press 5 now”, “To speak to our Operator press now 9 now ”, “To repeat these options press 0 now”.

To achieve the above mentioned scenario we need to type below code in our extensions.conf

[ivr]                                                    ;Main Context

exten => _X.,1,Answer()

exten => _X.,n,Wait(1)

exten => _X.,n,Playback(greeting-company-name)

exten => _X.,n,Read(option-press|options- company-name|1|skip|3)

exten => _X.,n,GotoIf($[${option-press} = 1]?option-press-1,s,1:6)

exten => _X.,n,GotoIf($[${option-press} = 2]?option-press-2,s,1:7)

exten => _X.,n,GotoIf($[${option-press} = 3]?option-press-3,s,1:8)      

exten => _X.,n,GotoIf($[${option-press} = 4]?option-press-4,s,1:9)

exten => _X.,n,GotoIf($[${option-press} = 5]?option-press-5,s,1:10)

exten => _X.,n,GotoIf($[${option-press} = 9]?option-press-9,s,1:11)

exten => _X.,n,GotoIf($[${option-press} = 0]?4:12)

exten => _X.,n,Hangup()

[option-press-1]                              ; Sub Context 1

exten => s,1,Dial(SIP/hr|60)

exten => s,n,Hangup()

[option-press-2]                              ; Sub Context 2

exten => s,1,Dial(SIP/sales|60)

exten => s,n,Hangup()

[option-press-3]                              ; Sub Context 3

exten => s,1,Dial(SIP/accounts|60)

exten => s,n,Hangup()

[option-press-4]                              ; Sub Context 4

exten => s,1,Dial(SIP/admin|60)

exten => s,n,Hangup()

[option-press-5]                              ; Sub Context 5

exten => s,1,Dial(SIP/it|60)

exten => s,n,Hangup()

[option-press-9]                              ; Sub Context 6

exten => s,1,Dial(SIP/operator|60)

exten => s,n,Hangup()

Description of above code:

First we have to define a context name within square brackets before writing script for extensions. For example, here we are using main context “[ivr]” and 6 sub contexts. So, let’s talk about main context first.

Priority 1: Application Answer is used to answer the channel if a call is placed on it.

Priority 2: Application Wait is used to let channel the wait for definite period of time before something else to be executed. Here we are using wait time equal to 1 second. This is optional here but it is good to use because sometimes when anyone calls from his/her VoIP device then he/she is not able to hear complete greeting due to delay.

Priority 3: Application Playback is used to play a sound file. Here “greeting-company-name” is the name of the sound file placed in /var/lib/asterisk/sounds/ directory. This sound file will play a greeting message as per the above scenario.

Priority 4: Here Application Read is used to play to sound file “options- company-name” and stores the option pressed by the user in a variable option-press. At the third place we are using 1 that informs asterisk to store only one pressed digit in the variable. By specifying skip, the application will not move further if the channel is not available and at last 3 indicates that if user doesn’t enter anything for 10 seconds then the sound file will play till the number of times specified.

Priority 5,6,7,8,9,10,11: Application GotoIf is a conditional application used to check the option pressed by user and if it is true then the channel will be directed to the specified context and if it is false then it will hangup the channel.

Priority 12: Application Hangup is used to disconnect the line.

Let’s discuss the sub contexts code:

All the sub contexts have almost same code.

Priority 1: Application Dial is used to place calls on a channel using desired technology (SIP, IAX, MGCP, ZAP, and DADHI). Here we are using SIP as technology to send the call to the specified extension, like hr, it, accounts etc.

Priority 2: Application Hangup is used to disconnect the line.

Note: In the next part I’ll make this IVR more efficient. Please provide your comments and suggestions so that I can keep improving my posts.