Browse Prior Art Database

Error Resistant Method for DTMF Key Entry of US State Codes

IP.com Disclosure Number: IPCOM000015758D
Original Publication Date: 2002-Mar-31
Included in the Prior Art Database: 2003-Jun-21
Document File: 3 page(s) / 125K

Publishing Venue

IBM

Abstract

Disclosed is a method for making the DTMF (Dual Tone Modulated Frequency telephone key) entry of United States state codes resistant to user input error. Description In DTMF-controlled Interactive Voice Response Systems (IVRS), it is difficult for users to select one item from a large list of items (for example, stocks). One such moderately large list is the list of U.S. states. Fortunately, there are official two-letter postal abbreviations for the U.S. states and territories. Unfortunately, ambiguities can occur when callers enter these codes using the telephone number keys (especially if users must select states for which they do not know the codes and guess rationally, but incorrectly). This disclosure describes a disambiguation strategy for this situation that is appropriate for IVRS. Solution The preferred embodiment strikes a reasonable balance between spelling the state name in its entirety and navigating a menu to resolve any remaining ambiguities. In the following example, the user was born in New Mexico (NM which corresponds to 66 and is unambiguous) and currently resides in Maryland (MD which corresponds to 63, which makes it ambiguous with NE, ME, and ND). System: Please enter the two-letter state code of your birth state. User: [66] System: New Mexico. Now please enter the code for the state in which you currently

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Error Resistant Method for DTMF Key Entry of US State Codes

  Disclosed is a method for making the DTMF (Dual Tone Modulated Frequency -- telephone key) entry of United States state codes resistant to user input error.

Description In DTMF-controlled Interactive Voice Response Systems (IVRS), it is difficult for users to select one item from a large list of items (for example, stocks). One such moderately large list is the list of U.S. states. Fortunately, there are official two-letter postal abbreviations for the U.S. states and territories. Unfortunately, ambiguities can occur when callers enter these codes using the telephone number keys (especially if users must select states for which they do not know the codes and guess rationally, but incorrectly). This disclosure describes a disambiguation strategy for this situation that is appropriate for IVRS.

Solution The preferred embodiment strikes a reasonable balance between spelling the state name in its entirety and navigating a menu to resolve any remaining ambiguities. In the following example, the user was born in New Mexico (NM - which corresponds to 66 and is unambiguous) and currently resides in Maryland (MD - which corresponds to 63, which makes it ambiguous with NE, ME, and ND).

System: Please enter the two-letter state code of your birth state. User: [66] System: New Mexico. Now please enter the code for the state in which you currently

reside.

    User: [63] System: For Maryland, press 1. For Nebraska, press 2. For Maine, press 3. For North Dakota, press 4.

User: [1]

Note that when there is only one state for a pair of DTMF keys, the user only needs to press two keys to unambiguously select a state. If there is more than one state for a pair of DTMF keys, then the user will need to press three keys -- two for the state code, and one for disambiguation. This is a well-known method when the system assumes that users know the appropriate state codes, but what if users do not know the correct state code for a given state (or territory), and make a rational but incorrect guess at it?

FIGURE 1 contains the first six DTMF code groups for US states and territories assuming correct and incorrect (but likely) user input. (For the complete table plus additional analyses, see Lewis & Sadowski,...