DTMF vs. Speech

DTMF vs. Speech

Although your first instincts are to simply speech enable your existing DTMF (touch tone) applications, doing so does not leverage the power and strengths of speech recognition. In other words, speech enabling a DTMF application will not make the system smoother, faster, or easier–to–use.

Migrating a DTMF application and prompt design does not fully utilize the conversational aspect of speech. For speech recognition applications to perform well, the call flow and dialog design is crucial. Designers must study the user patterns of the existing system, so they can redesign prompts, menus, and change the steps of the call flow to make the experience faster and more pleasant for callers.

The combination speech/DTMF system lengthens already complex menus, by adding the "press or say" routine — "For Checking, press or say 'one,'" or even worse, "For Checking, press one, or say 'checking'." The typical combination speech/DTMF system requires the caller to remember too much, putting undue burdens on them.

Therefore, well–designed speech recognition solutions offer many advantages over the combination speech/DTMF systems.

Speech is:

More Human
With speech, prompts are phrased as easy questions, and callers can answer simply and naturally — with their voices. Speech recognition systems provide a more "natural" interface than touch tone menus.

Smooth and Fast
Good speech call flow designs permit callers to get what they need more quickly, without having to wade through cumbersome filter menus.

Navigation is much simpler, and callers can use the application with the interface mechanism they are most familiar with: their voice.

More personal
Speech applications give the impression of the ideal employee: attentive, empathetic, alert, and consistently agreeable, rather than an impersonal string of numbers and tones.

The Exceptions: When to Use DTMF
Sometimes, DTMF is appropriate: as an error–handling backup, or in special, security–sensitive interactions, such as pin code or credit card entry. This is especially true if the caller has people around them, and they do not wish to speak their sensitive information out loud.


In terms of customer satisfaction, for most calls, speech recognition software outperforms DTMF. Rather than speech–enabling an existing DTMF system, design your application with a conversation in mind and learn to leverage the power of speech

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