System information

Components of an IVR
The most basic elements of an IVR are quite similar to those of an automated attendant,
though the goal is different. We need at least one prompt to tell the caller what the IVR
expects from him, a method of receiving input from the caller, logic to verify that the
caller’s response is valid input, logic to determine what the next step of the IVR should
be, and finally, a storage mechanism for the responses, if applicable. We might think
of an IVR as a decision tree, although it need not have any branches. For example, a
survey may present exactly the same set of prompts to each caller, regardless of what
choices the callers make, and the only routing logic involved is whether the responses
given are valid for the questions.
From the caller’s perspective, every IVR needs to start with a prompt. This initial
prompt will tell the caller what the IVR is for and ask the caller to provide the first input.
We discussed prompts in the automated attendant in Chapter 15. Later, we’ll create a
dialplan that will allow you to better manage multiple voice prompts.
The second component of an IVR is a method for receiving input from the caller. Recall
that in Chapter 15 we discussed the Background() and WaitExten() applications for
receiving a new extension. While you could create an IVR using Background() and
WaitExten(), it is generally easier and more practical to use the Read() application,
which handles both the prompt and the capture of the response. The Read() application
was designed specifically for use with IVR systems. Its syntax is as follows:
Read(variable[,filename[&filename2...]][,maxdigits][,option][,attempts][,timeout])
The arguments are described in Table 17-1.
Table 17-1. The Read() application
Argument Purpose
variable The variable into which the caller’s response is stored. It is best practice to give each variable in your IVR a name
that is similar to the prompt associated with that variable. This will help later if, for business reasons or ease of
use, you need to reorder the steps of the IVR. Naming your variables var1, var2, etc. may seem easy in the
short term, but later in your life cycle it will make fixing bugs more difficult.
prompt A file (or list of files, joined together with the & character) to play for the caller, requesting input. Remember
to omit the format extension on the end of each filename.
maxdigits The maximum number of characters to allow as input. In the case of yes/no and multiple choice questions, it’s
best practice to limit this value to 1. In the case of larger lengths, the caller may always terminate input by
pressing the pound key.
options s (skip) Exit immediately if the channel has not been
answered.
i (indication) Rather than playing a prompt, play an indication tone
of some sort (such as the dialtone).
n (noanswer) Read digits from the caller, even if the line is not yet
answered.
390 | Chapter 17: Interactive Voice Response