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Interactive Voice Response

Interactive voice response, or IVR, is a technology that allows a computer to detect voice and keypad inputs. IVR technology is used extensively in telecommunications.

Telephone keysWhat is IVR

The term interactive voice response (IVR) systems is used to describe a range of automated systems generally accessed through a telephone interface. Consumers frequently encounter IVR systems when placing calls to businesses. A caller may be greeted with the message to "Press 1 for balance enquiries," Press 2 for customer services," and so on.

IVR systems

IVR systems are an example of computer-telephone integration (CTI). The most common way for a phone to communicate with a computer is through the tones generated by each key on the telephone keypad. These are known as dual-tone multi-frequency (DTMF) signals.

Each number key on a telephone emits two simultaneous tones: one low-frequency and one high-frequency. The number one, for example, produces both a 697-Hz and a 1209-Hz tone that's universally interpreted by the public switched telephone network as a number "1".

A computer needs special hardware - a telephony board or telephony card to understand the DTMF signals produced by a phone. A simple IVR system only requires a computer hooked up to a phone line through a telephony board and some IVR software. The IVR software allows the business to pre-record greetings and menu options that a caller can select using the telephone keypad.

Other IVR systems include speech-recognition software that allows a caller to communicate with a computer using simple voice commands. Speech recognition software has become sophisticated enough to understand names and long strings of numbers.

On the other end of the phone call, a business can employ text-to-speech (TTS) software to fully automate its outgoing messages. Instead of recording all of the possible responses to a customer query, the computer can generate customized text-like responses and read it back to the customer using an automated voice.

Many of today's most advanced IVR systems are based on a special programming language called voice extensible markup language (VXML). VXML is the W3C's standard XML format for specifying interactive voice dialogues between a human and a computer. It allows voice applications to be developed and deployed in an analogous way to HTML for visual applications. Just as HTML documents are interpreted by a visual web browser, VoiceXML documents are interpreted by a voice browser.

The future of IVR

The increased usage of Voice Over Internet Protocol (VoIP) in voice networks is likely to affect how IVR will be used. This is due to the introduction of protocols such as SIP. The introduction of SIP means that communications are no longer restricted to voice calls but can now be extended to multimedia technologies such as video. This will bring a new meaning to automated services as IVR extends its reach to video calls.

Many IVR manufacturers are working on Interactive Voice and Video Response (IVVR) systems, especially for the mobile phone networks. The use of video will give IVR systems the ability to use graphical and video information to assist the caller.

The introduction of video IVR may allow systems in the future the ability to read emotions and facial expressions. It may be used to identify the caller, using technology such such as iris scan or other biometric means. Recordings of the caller may be stored to monitor certain transactions, and will be used to reduce identity fraud.

Common uses of IVR

TelephoneIVR systems are typically used to service high call volumes, reduce costs and attempt to improve the customer experience. Examples of typical IVR applications are: telephone banking, televoting, and credit card transactions. Large companies use IVR services to extend the business hours of operation.

Call centers use IVR systems to identify and segment callers. The ability to identify customers allows the business to tailor services according to the customer profile.

Voice-activated IVR systems are now used to replace the switchboard operators which are used in many hospitals and large businesses to reduce the caller waiting time. An additional function is the ability to allow external callers to page hospital staff and transfer the inbound call to the paged person.

The largest installed IVR platforms are used for applications such as voting in TV game shows which can generate enormous call spikes. IVRs have also been widely used to take orders for mobile content, such as ringtones and logos, weather forecasts.

IVR systems also allow callers to obtain data relatively anonymously. Hospitals and clinics have used IVR systems to allow callers to receive anonymous access to test results. This is information that could easily be handled by a person but the IVR system is used to preserve privacy and avoid potential embarrassment of sensitive information or test results.

Large pharmaceutical companies also use IVR systems to conduct global clinical trials and manage the large volumes of data generated. The caller will respond to questions in their preferred language and their responses will be logged into a database and possibly recorded at the same time to confirm authenticity.

Automated IVR systems provide a range of benefits to consumers. IVR systems often operate 24 hours a day, allowing consumers to conduct certain personal business at a time that is convenient for the caller, regardless of a company’s business hours. However, IVR systems can also lead to a sense of frustration for consumers hoping to speak to a live person who can answer a question or provide technical support.

Problems encountered by disabled people and the ageing population using IVR

Basic operation of IVR systems requires that users listen to, understand and respond to system prompts and in some cases enter personal data. Each of these steps can present a problem to individuals with disabilities. In addition, in an effort to reduce costs, many companies appear to be designing their systems to reduce or eliminate consumer access. Without access to a human operator, consumers with disabilities have even fewer options for accessing services via the telephone.

Hearing impaired

IVR systems pose significant accessibility barriers to people who attempt to use the mainly American method of TeleType Writers (TTYs) to directly interact with these systems.

Few IVR systems have been implemented that provides users with a choice to use Baudot tones. Baudot tones are characters and numerals transmitted as a series of pulses deciphered by the TTY back into original text form.

TTY users may even have difficulty knowing that they are connected to an IVR system if the system does not provide TTY prompts. They may experience difficulty interacting with the system since some TTYs do not have the capability to generate the touch-tones required to respond to the system prompt. TTY users may also become confused when, for example, the IVR system states "Press 1 for balance enquiries" and the user presses 1 on the TTY, generating a Baudot tone for 1 rather than a DTMF tone as required by the system.

For most UK based people who are hearing impaired and use textphones IVR can cause siginificant problems without either: the intervention of a third party such as a relay service (e.g. TextDirect), a family member, friend or colleague; the inclusion of a function to interact through text messages and the ability to receive textphone input and the provision of an alternative contact number through a dedicated textphone access point.

Call centre operatorIn an attempt to assist customers TextDirect maintains a list of call routing and IVR systems and connects a Relay Operator into the call before the customer is connected. According to the Employer's Forum on Disability & BT (2006), many textphone users prefer not to use relay services so best practice for companies is to provide dedicated textphone numbers.

A further significant barrier faced by relay service users is that many systems time out before the user has a chance to make a selection. Most IVR systems do not provide the user or relay operator with an opportunity to pause the system or replay an individual menu item.

People who are hard of hearing can also find IVR or relay systems difficult to use due to the audio quality of the system messages. The volume, speed and level of background sounds can also influence a user’s ability to access the system successfully.

Physically impaired

Users with physical impairments may not be able to respond to prompts before the IVR system times out. Other accessibility issues could also be caused by users having difficulties with the telecommunication equipment.

Cognitively impaired

In addition to listening and responding to prompts, IVR systems often require users to enter personal data such as a telephone number, account number, or post code. People with coginitive impairments would require adequate time to be given to be able to respond to data entry requests.

Also, users with cogintive impairments may benefit from a request to repeat the voice prompts and in some cases IVR systems have too many menu options which can cause confusion for customers.

Ageing population

Members of the ageing population who are unfamiliar with IVR systems can easily become confused by them as improvements in synthetic speech synthesisers are resulting in systems that sound as if the caller is speaking to a live person. As with individuals who are hard of hearing, even recognizing that they have reached an IVR system could be a problem.

Similarly, like those who have cognitive impairments, the ageing population may also require extra time to enter data or respond to system prompts and would also benefit from a repeat listening facility.

Checklist for IVR


Menu options

  • Messages need to be kept short, and should include some prominent key words
  • Use consistent terminology
  • The most important or the most commonly selected items in a menu should be presented first in a list
  • Menu options are be based on why customers call, not organisational structure
  • Menu options should be reviewed regularly checking usage and customer feedback
  • Menus should not exceed four choices
  • Menus should have no more than three levels or ‘sets’ of options
  • Voice prompts should be recorded professionally in a studio to enhance clarity
  • Announce the function, and then the key required to activate it
  • Give customers two or three chances to select an option
  • The system should transfer a caller to an operator if no option is chosen
  • Provide different audio feedback for valid and invalid key presses
  • Provide verbal feedback for choice confirmation
  • Always have a repeat facility. Best practice is for the repeat to occur automatically rather than relying on the customer selecting to hear the options again


  • Indicate where the customer is in the queue and the approximate time before the call will be answered – update the customer at reasonable intervals
  • Ensure the system is consistent
  • Provide music as an indication of being in a queue

User responses

  • Allow for users who need extra time to respond to prompts
  • Keep user IDs to no more than 8 digits
  • Do not require that the same information is entered more than once

Ending the call

  • Systems should have a message at the end telling the user that the transaction is completed
  • A best practice message will tell the user not only that the transaction is complete but that they are free to end the call. A key press option, e.g. press 9 to end the call, could also be given

Call centre headsetHelp facilities

  • Provide an option in the menu to access a human operator
  • Provide a recovery route from error
  • Provide context-sensitive help
  • All customer service staff, advisers and call centre staff are given disability awareness training


  • AS 5061 (2008) Interactive voice response systems user interfaces - Speech recognition
  • AS/NZS 4263 (2003) Interactive voice response systems - User-interface - Dual tone multi frequency (DTMF) signalling
  • ETSI ES 00077 - Human Factors: Harmonised relay services for text telephones
  • ETSI ETR 333 (1998) Human Factors (HF); Text Telephony; Basic user requirements and recommendations
  • ETSI TR 101 806 (2000) Human Factors: Guidelines for telecommunications relay services for text and video
  • FCC Section 255 Telecommunications access for people with disabilities
  • ITU-T E.902 (1995) Interactive services design guidelines
  • ITU-T Recommendation Q.23 (1988) Technical features of push-button telephone sets

Further information


The information contained in this section was taken from the following sources:

The author would like to thank F. Miller and T. Shipley for their additional comments and advice.