The present invention relates to a voice response unit, and more particularly, to a voice response unit having application in an enhanced services environment.

BACKGROUND OF THE INVENTION Voice response units are well known in telephony systems.

They allow a caller to enter and retrieve information by using the telephone keypad to respond to a voice menu. They can provide, for example, the playback of prerecorded, or voice synthesization of, successive digits in a telephone number in response to a request for directory assistance. In other instances, they may provide voice confirmation of a number entered into a remote unit by depression of the dual tone multiple frequency dialing push buttons of a telephone.

The problem of providing a response becomes more complex when the voice response unit is used to construct phrases in providing voice prompts for the subscriber in enhanced services platforms such as prepaid telephone systems, e. g.,"You may talk for ten minutes", or"Your account balance is ten dollars and thirty cents."The various messages or phrases (if the message is to be concatenated) must be prerecorded or synthesized. The number of the messages expands dramatically when the voice response unit is required to provide the voice prompts in plural languages, where the grammatical rules of construction and the gender of the words may differ significantly in the construction of any given phrase.

Accordingly, it is an object of the present invention to obviate many of the deficiencies of known voice response systems and provide a novel voice response unit and method.

It is another object of the present invention to provide a novel voice response unit and method in which languages may be added without materially increasing the size of the language code base, i. e., as little as one line of code may be sufficient.

It is still another object of the present invention to provide a novel voice response unit and method in which the generation of voice response prompts includes the consideration of factors such as the gender of nouns, the location of digits in the phrase, the use of"and"between whole and decimal portions of numbers, etc., all without modification of the language code base.

These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a functional block diagram showing the basic organization of the enhanced services system of the present invention in the embodiment of a prepaid telephone system.

Figure 2 is a functional block diagram of an embodiment of the present invention showing the voice response unit (VRU) embedded within the switching platform.

Figure 3 is a high level functional block diagram showing the information exchange between the prepaid system and the language object of the embodiment of Figures 1-2.

Figure 4 is a matrix of language properties associated with the language object of Figure 3.

Figure 5 is a flow chart illustrating a typical exchange between a caller and a prepaid system.

Figure 6 is a flow chart illustrating the operation of the matrix of Figure 4 in connection with a language menu.

Figure 7 is a flow chart illustrating the operation of the matrix of Figure 4 in connection with an account balance.

DESCRIPTION OF PREFERRED EMBODIMENTS With reference to Figure 1 where an enhanced services platform is illustrated in the embodiment of a prepaid telephone system, a suitable conventional telephone switch 10 such as the Harris Corporation 20/20 switch is connected in a conventional public switched telephone network (PSTN).

Connected to the switch 10 are large numbers of subscriber telephones such as the caller telephone 12 and the called party telephone 14. Also connected to the switch 10 may be a bank of voice response units (VRUs) 15 on which the prepaid call processing application resides.

Alternatively as shown in Figure 2, the VRU may be embedded within the architecture of an integrated network server (IN Server) 16 which is physically mounted on the back plane of the telephone switch 10. The embedding of the VRU in the switch platform effects seamless transfer of information and may be accomplished by means of an adaptor card with the elimination of the Tl and E1 circuits. Where the VRU is embedded within the server, the server may be referenced as a voice application server or VAS.

The VRU 15, in conjunction with the prepaid call processing application, controls the construction of the desired voice message from prerecorded or synthesized files and the transmission of the desired voice message to the user.

Within the prepaid call processing application is a language object 18 which implements the language-by-rules concept of the present invention. The language object 18 identifies and creates the voice file names for each of the various voice prompts which the prepaid application requires be played by the VRU 15 to the caller 12.

As shown in Figure 3, the occasion of a prepaid debit call by the. caller 12 of Figure 1 causes the prepaid application 17 to request that the language object identify the voice files necessary for the VRU 15 of Figures 1-2 to construct and/or play the desired phrase in the desired language. The language object 18, under the control of the language rules discussed below, provides the identification of the voice file names to the prepaid application 16 which, in conjunction with the VRU 15, effects the operative voice connection to the caller 12 through the switch 10.

As shown in Figure 4, the language object includes a matrix with rows of languages which the object 18 supports and columns of various properties of the language. Languages may be added to the matrix at any time the code is compiled for the prepaid application. Similarly, the language rules of the matrix may be changed and/or new columns added to the matrix at any compilation of the code for the prepaid application.

By way of example only, the Harris prepaid telephone system plays the messages indicated in the flow chart of Figure 5. As shown in Figure 5, the caller 12 dials into the prepaid telephone system and upon connection is offered a choice of languages in which to proceed with the interaction. After selecting the desired language by keypad entry, vocal response, etc., the caller's personal identification number ("PIN") is requested. Upon PIN validation, the account balance of the caller may be provided and the call destination is requested by the prepaid system. After the caller has entered the call destination, the prepaid system determines the amount of time available for the call and provides the information to the caller. During the call, voice messages pertaining to time warnings/call termination may be provided to the caller.

Each of the foregoing messages may be constructed through the concatenation of various voice prompts by the prepaid call processing application 17 within VRU 15 once the language object 18 has identified the appropriate files. It is in the identification of the VRU voice files that the language object 18 acts as facilitator. In order to accomplish accurate phrasing for the voice prompts, the language object maintains various grammatical rules for each language that is supported.

To keep organization of these rules as flexible as possible, the language object uses a matrix of language properties.

For example, the gender of units such as dollars or lire may vary, and an amount of money may be stated"six dollars and fifty cents"or"three pounds ten pence". The rules for pluralities may also vary for words commonly used such as "minute","second","dollars"and"cents". Using the matrix of Figure 4, the language object reads the rules of the language and uses these rules to identify the VRU files which construct the desired phrase.

Example 1: The flow chart of Figure 6 illustrates how the matrix of the present invention may be used to construct a voice prompt relating to the menu of languages.

Upon accessing the prepaid system, the caller is provided with a language selection menu. For example, a message providing the choices of English, Turkish, and Italian may say: "For English, press 1. Turkce icin 2 basiniz. Per ascola in Italiano, premere 3".

The grammatical construct of the individual language segments of the message is achieved through the concatenation of prerecorded voice prompts. For example, the English segment is generated through the concatenation of a first phrase"For English, press"with a second phrase"1". Different grammatical constructs are associated with the different languages. The Turkish segment, for example, has a three phrase construct requiring the concatenation of the three phrases"For Turkish","2", and"press".

As shown in Figure 6, for each language segment of the language menu message, the language object 18 identifies a Language Menu A corresponding to the first phrase of the segment, the gender of the digit to be played, and, depending on the grammatical construct of the specific language, any additional phrases necessary to complete the message segment (e. g., for the Turkish segment, Language Menu B would correspond to the phrase"press").

Example 2: The flow chart of Figure 7 illustrates how the matrix of the present invention may be used to inform the caller of the balance in the caller's prepaid account. Upon accessing the prepaid system, the caller may be told, in English for example, that"The balance on your card is twelve dollars and thirty five cents". The grammatical construct in other languages may be more like"The balance on your card is twelve dollars thirty five cents remaining".

As shown in Figure 7, the language object 18 takes into consideration the possible variations of the different languages, with the account balance message generally taking the form : <Balance A><whole number><whole currency> ["and"] [decimal number] [currency] [Balance B] with the standard portions in'<>'and the optional portions, depending on the specific language construct, in' []'.

There are many benefits associated with the use of a matrix of language properties in the language object. For example, the addition of a new language simply requires the addition of a new row to the matrix while additional properties can be added to the matrix through the addition of a new column. Further, since these modifications are made only to the matrix, no other portions of the language object are affected.

While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof.