Tuesday, August 19, 2008

Guest Column: Developing IVR Applications by Uttam Pegu

The most essential requirement of an IVRS is that it has to work 24 hours a day, 364 days a year! It is not an application like your MS Word or Outlook Express that you run them when you need! Also IVRS does not have any User Interface. The reason for not having User Interface is obvious! It interacts with human through voice and telephone instrument keypad. (These are actually DTMF Digits. I will explain about DTMF, Pulse dialing in another post.) So, a typical IVRS application does not require to be executed manually, it starts as a service in Windows Operating System as soon as it boots up. ( Or same way in Linux)So, in order build an IVRS Application, the following are essential
1. How many channels to be used? How many calls it should handle simultaneously?
2. How should it be connected to PSTN Lines? Connection may be in two modes, analog and digital.
3. Type of Hardware used. It requires two kind of hardware – a. A PC or a Server b. CTI hardware.
4. Voice prompts Recording or TTS (text-To-Speech) Engine.
5. IVRS Software.
6. Power supply and wiring arrangement.
Number of channels greatly depends on number of calls the user is expecting. For example, if it is public utility (Like 100, 101, Railway enquiry etc), the number of calls will be high. If it has to handle large number of calls (more than 16 numbers), it should be connected using DIGITAL technology. And you will have to use a digital CTI cards too. Digital Cards are more expensive than analog CTI cards and they start with minimum channel count of 30. If you are going to use a Digital card, use a Server. There are many CTI cards, both analog and digital, available in various configurations.
Then the voice prompts! These are voices you hear as soon as you dial the IVRS telephone numbers! These are pre-recorded voices which are played as soon as your call is established. Normally one should get recorded the voice prompts and for any dynamic content or data, TTS may be used. But the voice quality of TTS is still poor specially it may be difficult to understand to people whose mother tongue is not English.
Once you finalized the above, it is time to develop your IVRS Software or find a IVRS Software development company! There are many IVRS Software development companies in the world. Many IVRS Software are developed on various platforms, using different languages. The best IVRS (in terms of robustness, features, easy to configure and maintain) are the IVRS software which are developed in C++. If you intend to develop a IVRS Software on your own, buy the CTI hardware, and read the APIs. Also you need to have thorough knowledge of PSTN exchange. Specially to configure DIGITAL CTI card using SS7, MTP3 ISUP, R2MF, ISDN PRI etc are time consuming and let me warn you, they are not easy! Also you have to have these infrastructure to your testing purpose! ( How many of you have an exhange with SS7 ?) So, best advice is, attempt build your own IVRS if you have to use analog CTI cards, and for DIGITAL CTI Cards, better contact some IVRS Companies!



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