1、 ITU-T RECMN*F.%R2 95 4862591 0600357 T7T INTERNATIONAL TELECOMMUNICATION UN ION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU OPERATIONS AND QUALITY OF SERVICE HUMAN FACTORS F.902 (02/95) INTERACTIVE SERVICES DESIGN GUIDELINES ITU-T Recommendation F.902 (Previously “CCITT Recommendation”) I
2、TU-T RECMN*F.902 95 m 4862593 Ob00358 90b = FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them wit
3、h a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Re
4、commendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation F.902 was prepared by ITU-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 21st February 1995. NOTE
5、 In this Recommendation, the expression ?Administration? is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1995 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or
6、 mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*F-902 95 = 48b259L Ob00359 842 m CONTENTS Page 1 Summary 1 2 Scope 3 References 4 Definitions 5 Abbreviations . 6 Guidelines 6.1 Procedures 6.2 Opening message 6.3 Prompts . 6.4 Error handling
7、. 6.5 Feedback . 6.6 Preparation of messages . 6.7 Usability testing 8 Bibliography . 1 1 1 3 3 3 4 4 4 4 5 5 5 Recommendation F.902 (02/95) 1 ITU-T RECNN*F-702 75 4862573 Ob00360 5b4 9 SUMMARY This Recommendation provides guidance for the design of basic procedures for the use of interactive teleco
8、mmunications services using DTMF input and voice response. These services are accessible from any DTMF telephone, or from pulse-dialling telephones with the use of an adjunct DTMF dialling device. Il Recommendation F.902 (02/95) ITU-T RECMN*F*902 95 H 4862573 06003b3 4TO H Recommendation F.902 INTER
9、ACTIVE SERVICES DESIGN GUIDELINES (Geneva, 1994) 1 Summary This Recommendation provides guidance for the design of basic procedures for the use of interactive telecommunication services using DTMF input and voice response. These services are accessible from any DTMF telephone, or from pulse- diallin
10、g telephones with the use of an adjunct DTMF dialling device. Consequently, the users control of the service must be accomplished solely by the use of the 12 buttons of the DTMF dial (0-9, plus * and #). Recorded spoken messages or tones, called “prompts”, are used to provide choices, guidance and f
11、eedback to users, and to ask for input of data such as telephone numbers, account numbers, time of day, etc. Choices are usually provided in the form of spoken “menus” that indicate which response (DTMF button) is associated with each available choice. If these guidelines are carefully observed and
12、good human factors design practices are followed, users should find such services easy to use, enhancing user satisfaction with them. 2 Scope Interactive voice response equipment makes possible a variety of interactive services, in which users may control the operation of the service through the use
13、 of a DTMF telephone. These include transaction services, voice messaging, information retrieval and various supplementary services. This Recommendation is intended to provide general guidelines for the design of such services to ensure that they will be easy to use for customers and to provide some
14、 degree of consistency across services. It is intended to cover all such services in which the control by the customer is exercised through the 12 keys of a DTMF telephone set (the digits 0-9 plus * and #), and which provide prompting messages and responses in the form of recorded or synthesized spe
15、ech. It does not include similar services controlled by voice commands interpreted either by human operators or by automatic speech recognition equipment. 3 References The following Recommendations and other references contain provisions which, through reference in this text, constitue provisions of
16、 this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision: all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations a
17、nd other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - - CCIT Recommendation E.183 (1989), Guiding Principles for Telephone Announcements. ISO/IEC JTC 1/SC 18 N 4420 Revised Text of ISO/IEC 13714, Information Technology - Document Processing a
18、nd Related Communication - User Inteace to Telephone-based Services: Voice Messaging Applications. Proposed draft International Standard, 15 November 1993. Source: ISOAEC JTC 1/SC 18NG 9. 4 Definitions For the purposes of this Recommendation, the following definitions apply: 4.1 context in which the
19、y are presented. adaptive guidance: User-tailored prompting, feedback or help messages that differ depending on the specific 4.2 code: String of digits (0-9 plus * and #) to be dialled to access a service. Recommendation F.902 (OW95) 1 ITU-T RECMN*F.902 95 m 4862591 0600362 337 m 4.3 (see above). co
20、mmand: A request by the user for the system to perform some function. It is invoked by entering a code 4.4 default dialog: System action that occurs in the absence of specific user request for a different dialog. 4.5 delimiter: Symbol (* or #) used to logically separate parts of an entry. 4.6 dial-a
21、head: The ability to enter DTMF input before the system has requested it. It is commonly used for rapid entry of data or a series of menu choices. In dial-ahead, a user enters a key-press or key-presses in advance of the associated prompt(s) and the output of these further prompt(s) associated with
22、the input key-press(es) is suppressed. Recommendation. NOTE - This term may also be referred to as a key-ahead, or type-ahead. The term dial-ahead is used in this 4.7 at the end of the system output. dial-through: The interruptions of the system output with DTMF input acted on just as if it had been
23、 entered NOTE - This term may also be referred to as key-through or cut-through. The term dial-through is used in this Recommendation. 4.8 dialling device: DTMF device acoustically coupled to a telephone set. 4.9 be found in CCITT Vol. VI, Recommendation Q.23. DTMF: Dual tone multi-frequency encodin
24、g of key-press input. The definition of the encoding employed may 4.10 DTMF device: A device through which a user can generate (or, in the case of the equipment such as digital telephones, duplicate the effect of) the DTMF tones associated with the keys 0-9, * and #. This device is typically a DTMF-
25、telephone but may also be a tone generator, a digital telephone used to invoke DTMF signals from a telephone switch, or a digital telephone. 4.11 feedback: Information supplied by the system to indicate that the user actions have had their intended effects, or have had unintended effect. Typically,
26、feedback consists of a new prompt or message indicating that an action has had its intended effect, but feedback also includes error indications and tones. 4.12 going off-hook: Picking up the receiver or equivalent action to activate a telephone set. 4.13 and unprompted choices, and of their current
27、 place in the system. help: Information provided, either automatically or upon request, to inform users of their available prompted 4.14 main menu: The first menu encountered in the dialog when accessing a service. 4.15 each describing an available function and the user action necessary to invoke th
28、at function. menu: The presentation to the user of a list of possible actions. A menu typically consists of a set of prompts 4.16 requirements in order to access a telephone terminal. people with special needs: Categories of users (e.g. elderly, children, disabled, travellers) who have special 4.17
29、or synthesized voice and/or tones. prompt: Auditory system output providing instructions or guidance to the users. Prompts consist of recorded 4.18 teller machine: Automatic cash dispenser. 4.19 time out: I) 2) An interval of no user input that causes the system to change state. The state change res
30、ulting from such an interval. For example, a time-out during numeric input may be interpreted as end-of-string and cause the system to change from numeric input state to command state or some appropriate action state. 4.20 user interface: Software and hardware components through which a user can int
31、eract with a system. 4.21 user-tailored menus: Menus which are flexible so as to meet the different needs of the users. 2 Recommendation F.902 (OZ95) ITU-T RECMN*F=902 95 4862593 06003b3 273 5 Abbreviations For the purpose of this Recommendation, the following abbreviations are used: CCITT DTMF Dual
32、 Tone Multi-Frequency IEC International Electrotechnical Commission IS0 International Organization for Standardization ITU-T International Telephone and Telegraph Consultative Committee International Telecommunication Union - Telecommunication Standardization 6 Guidelines 6.1 Procedures 6.1.1 The be
33、nefit-to-cost ratio of the user access procedures should be optimized. In particular, for common and frequent procedures, entering long unstructured strings of digits should be avoided (e.g. by means of default values, logical codes, user-tailored menus, dialling devices), or such strings should at
34、least be partitioned into logical chunks. 6.1.2 User procedures should be easy to learn. The design should facilitate the cognitive transfer of a user experience with similar services. The users should be able to generalize their experience from parts of the system to other parts of the system. 6.1.
35、3 and teller machines should be similar). The design should not violate user expectations (e.g. the user procedures for using credit cards with telephones 6.1.4 The user interface should be adequate to the complexity of the service and the capabilities of the user. The user interface designer should
36、 consider the differing needs of frequent, sophisticated users and infrequent or new users. The cognitive load of the access procedures should be transferred from the user to the terminal or network by the use of suitable technology, as it becomes available. Example: The user should be allowed to in
37、voke the service by name (Automatic Speech Recognition) or to pick it up from a menu displayed on a screen (screenphones). 6.1.5 the means of payment both before and after going off-hook, both orders of operation should be allowed. User procedures should be flexible to accommodate individual prefere
38、nces. For example, if users tend to enter 6.1.6 indicate the end of input). Similar commands should be used to access similar functions (e.g. the same delimiter should be used to 6.1.7 message, press 1 now”). When stating options in a menu, always present the choice first, then the action to achieve
39、 it (e.g. “TO send a 6.1.8 of digits and keying stops in mid-entry, then wait at minimum 3 and at maximum 8 seconds before timing out). The speed of the interactive dialogue should not create anxiety in the user (e.g. if the user is enterhg a string 6.1.9 Where universal (i.e. context-independent) c
40、ommands, such as accessing help or returning to the main menu, are available, they should be preceded by the * key to preserve the remaining keys for context-dependent use. For example *4 might be used for “help”, *7 for “return to main menu”. Where they are widely available, the letters on the tele
41、phone keypad can be used to help users remember universal commands. For example, *H could be used to access “help”. Recommendation F.902 (02/95) 3 6.2 Opening message 6.2.1 Upon accessing a service a user should be presented with a welcome message identifying the service and making it clear the serv
42、ice is an automated one (e.g. “Welcome to the Universal Personal Telecommunications automated service”). 6.2.2 It would also be advisable to verify the user is calling from a DTMF device. 6.3 Prompts 6.3.1 inactivity a message or a default dialogue should be provided. The user should be helped throu
43、gh the procedures by means of voice prompts. In the case of prolonged user 6.3.2 Prompts should be kept short, in order to avoid exceeding the capacity of the users short-term memory (e.g. only four, or at the most five, choices should be presented on a single menu; choices should be numbered sequen
44、tially in ascending order and presented in decreasing order of frequency of use or grouped by logical functions). In the case of long menus, human memory load should be minimized by allowing users to hear the menu choices repeated. This may be provided either automatically or as a result of a user r
45、equest. 6.3.3 described in each menu, but should be described in help messages or through user documentation. Universal commands (e.g. “return to main menu”, “delete”, etc.) that are always available should not be 6.3.4 them. This permits experienced users to speed the use of the service and minimiz
46、e frustration. When listening to prompts, user should be allowed to dial-through and dial-ahead, i.e. to intempt and by-pass 6.3.5 feedback or for indicating when to speak to record a message. The use of tones as prompts should be limited to avoid confusing users. Tones may best be used for error 6.
47、3.6 used mainly by infrequent users, it may need longer, more detailed prompting messages. When the service is used typically by frequent users, it may need only brief prompts, but when the service is 6.4 Error handling 6.4.1 error messages, re-prompting or adaptive guidance). The system should be e
48、rror tolerant and, possibly, prevent errors (e.g. through the use of context-sensitive 6.4.2 User-friendly error recovery procedures should be available. For example, upon entering invalid information, a user should be given a chance to re-try. Besides, if an error was made in the middle of a long p
49、rocedure, the user should be asked to repeat just the last step, not to start the entire procedure fi-om the beginning. Uninterruptible error messages may be needed to help users who make use of dial-ahead. 6.4.3 The users should be allowed to cancel data entry or actions that a user cannot recover from. 6.4.4 “Your calls will be sent to N”NNN. To confirm, press 1 now; to re-enter, press 2”). In the case of important, irreversible or critical actions, the user should always be asked for confirmation (e.g. 6.4.5 Help should be available at any time. 6.4.6 inactivity of the user. Help,
