CA2014797A1 - Storage control method and apparatus for an interactive television terminal - Google Patents
Storage control method and apparatus for an interactive television terminalInfo
- Publication number
- CA2014797A1 CA2014797A1 CA002014797A CA2014797A CA2014797A1 CA 2014797 A1 CA2014797 A1 CA 2014797A1 CA 002014797 A CA002014797 A CA 002014797A CA 2014797 A CA2014797 A CA 2014797A CA 2014797 A1 CA2014797 A1 CA 2014797A1
- Authority
- CA
- Canada
- Prior art keywords
- screen
- terminal
- data
- memory area
- processor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/162—Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
- H04N7/165—Centralised control of user terminal ; Registering at central
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/21—Server components or server architectures
- H04N21/214—Specialised server platform, e.g. server located in an airplane, hotel, hospital
- H04N21/2143—Specialised server platform, e.g. server located in an airplane, hotel, hospital located in a single building, e.g. hotel, hospital or museum
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
- H04N21/254—Management at additional data server, e.g. shopping server, rights management server
- H04N21/2543—Billing, e.g. for subscription services
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/47—End-user applications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/47—End-user applications
- H04N21/472—End-user interface for requesting content, additional data or services; End-user interface for interacting with content, e.g. for content reservation or setting reminders, for requesting event notification, for manipulating displayed content
- H04N21/47202—End-user interface for requesting content, additional data or services; End-user interface for interacting with content, e.g. for content reservation or setting reminders, for requesting event notification, for manipulating displayed content for requesting content on demand, e.g. video on demand
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/08—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division
- H04N7/087—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division with signal insertion during the vertical blanking interval only
- H04N7/088—Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division with signal insertion during the vertical blanking interval only the inserted signal being digital
- H04N7/0888—Subscription systems therefor
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
- H04N7/1675—Providing digital key or authorisation information for generation or regeneration of the scrambling sequence
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/173—Analogue secrecy systems; Analogue subscription systems with two-way working, e.g. subscriber sending a programme selection signal
- H04N7/17309—Transmission or handling of upstream communications
- H04N7/17318—Direct or substantially direct transmission and handling of requests
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/47—End-user applications
- H04N21/478—Supplemental services, e.g. displaying phone caller identification, shopping application
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Computer Security & Cryptography (AREA)
- Databases & Information Systems (AREA)
- Human Computer Interaction (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Controls And Circuits For Display Device (AREA)
Abstract
STORAGE CONTROL METHOD AND
APPARATUS FOR AN INTERACTIVE
TELEVISION TERMINAL
ABSTRACT OF THE DISCLOSURE
An interactive terminal comprises a processor, a local data store connected to the processor, a character generator responsive to processor control for generating a television signal output to an asso-ciated television receiver, a key pad or remote control for inputting information to the processor, and a power supply input. The terminal is coupled, via 2-way RF communications, to a central location, desig-nated as the system manager, where the terminal is accessed by poll-ing for monitoring and servicing terminal user requests. The interac-tive terminal has a local storage capacity for storing a number of character screen commands, accessed from a central data base at the system manager, for use in generating prompting screens displayed on the television receiver. In use, a user may call for a variety of serv-ices by operating the input keys of the key pad to cause a prompting screen to be displayed. Screen commands are stored at the terminal according to an assigned priority. The stored screen commands also include pointers which are used by the terminal processor to prefetch screens which will likely follow the current screen in a decision tree structure manner. Thus, screens may be prefetched from the central data base and downloaded for storage at the terminal so that they are available for display if and when called for. If a particular branch of a decision tree is not selected, screens associated with the unselected branch are deleted from terminal memory as needed to make room for new screens. The terminal memory is also controlled so that data is swapped in and out of memory based on its relative priority.
APPARATUS FOR AN INTERACTIVE
TELEVISION TERMINAL
ABSTRACT OF THE DISCLOSURE
An interactive terminal comprises a processor, a local data store connected to the processor, a character generator responsive to processor control for generating a television signal output to an asso-ciated television receiver, a key pad or remote control for inputting information to the processor, and a power supply input. The terminal is coupled, via 2-way RF communications, to a central location, desig-nated as the system manager, where the terminal is accessed by poll-ing for monitoring and servicing terminal user requests. The interac-tive terminal has a local storage capacity for storing a number of character screen commands, accessed from a central data base at the system manager, for use in generating prompting screens displayed on the television receiver. In use, a user may call for a variety of serv-ices by operating the input keys of the key pad to cause a prompting screen to be displayed. Screen commands are stored at the terminal according to an assigned priority. The stored screen commands also include pointers which are used by the terminal processor to prefetch screens which will likely follow the current screen in a decision tree structure manner. Thus, screens may be prefetched from the central data base and downloaded for storage at the terminal so that they are available for display if and when called for. If a particular branch of a decision tree is not selected, screens associated with the unselected branch are deleted from terminal memory as needed to make room for new screens. The terminal memory is also controlled so that data is swapped in and out of memory based on its relative priority.
Description
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STORAGE CONTROL METHOD AND
APPARATUS FOR AN INTERACTIVE
TELEVISION TERMINAL
This application is a- continuation-in-part of application Serial No. 289,21~, filed December 23, 1988, and entitled ~AutOmatic Inter-active Television Terminal Configurationl~ and is related to U.S.
Application Serial Nos.: , (Attorney Docket No.
25,871), entitled ~Cable Television Transaction Terminal~;
, (Attorney Docket No. 25,872), entitled ~Terminal Authorization Method~; (Attorney Docket No.
25,S74), entitled ~Terminal Polling Method";
(Attorney Docket No. 25,~7~), entitled "Interactive Television Ter-minal with Programmable Bac~ground Audio or Video"; and , (Attorney Docket No. 25,8~8), entitled ~Interactive Room Status/Time Information System", filed concurrently herewith.
TECHNICAL FIELD
This invention relates generally to two-way interactive cable television systems in which entertainment services, information and data signals are provided over cable facilities from a system manager location to a user location, and more particularly to a method and apparatus for controlling the storage of data in local storage at the user location.
BACKGROUND OF THE INVENTION
Two-way interactive cable television systems are known for transmitting entertainment, information and data signals over a cable facility toward a plurality of users. Data may be transmitted and addressed to a particular subscriber over a separate data channel or over a so-called llin-band" data channel. In a downstream direction, addressed control data may represent services authorized tO a partic-ular terminal or control commands to that terminal. In an upstream .
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direction from a terminal to the service provider or system manager location, control data may represent selections made by a user in response to a polling request or at the time of user selection.
In a hotel environment, the s-ystem manager delivers video signals, e.g., television programming, to user terminals located, for example, in various hotel rooms o~er cable lines, and the system man-ager also transmits digital messages to receivers at each room loca-tion. Similarly, information and data generated at each room are transmitted upstream to the system manager via the cable.
It is known in the prior art to provide an interactive terminal at a user location including a local processor for controlling access to a host computer located at the system manager location and a local data store connected to the local processor. Such termina~s also nor-mally consist of a display for displaying messages to the user or details of the transaction being conducted, and a keyboard or remote key pad comprising a number of keys by which the user can enter data and initiate functions.
Typically, a central data storage is provided at the system manager location for storing a complete data base, and a smaller su~
set of that data base is maintained in the local store at the user ter-minal. Because faster response times can be achieved if a requested transaction can be completed without the need for repeatedly access ing the central data base, configuration of the local store becomes an important design consideration. Prior methods of local storage man-agement have been based upon last use or recency of use, and systems are also known in which those items in the data base most frequently re~uested by the user terminals are retained in the local store. These methods have not, however~ been entirely satisfactory, and have not uniformly achieved the desired reduction in response time. Accord-ingly, there is a need for a more efficient technic,ue for choosing data items to be stored in a local storage of an interactive terminal sys~em.
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SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved method of local storage management for an interactive terminal which ensures faster response times and which reduces the need for repeatedly accessing the central data base.
It Is another object of the present invention to provide a method o~ local storage management for an interactive terminal whi~h updates the local store in accordance with the relative priority of data entries.
It is still another object of the present invention to provide a method OI local s~orage management which updates the local store in accordance with the system service requested by the user.
An interactive terminal, according to the present invention, comprises a processor, a local data store connected to the processor, a character generator responsive tO processor control for generating a television signal output to an associated television receiver, a key pad or remote control for inpu~ting information to the processor, and a power supply input.
In a hotel environment, the interactive terminals are located in individual hotel rooms and are coupled, via 2-way RF communica-tions, to a central hotel location, designated as the system manager, where the terminals are accessed by polling for monitoring and ser-vicing the guests~ requests. The local storage capacity of the interac-tive terminal is provided for storing data and a number of character screen commands, accessed from a central data base at the system manager, for use in generating prompting screens displayed on the teleYision receiver. Thust in use, a hotel guest may call for a variety of services, e.g., pay T~7 programs, room service and the like, by ope~
ating the input keys of the key pad to cause a prompting screen to be displayed on the television receiver.
According to the invention, character screen commands are stored at the terminal according to an assigned priority. The stored screen commands also include pointers which are used by the terminal processor to prefetch other screens which follow the current screen in a deci~sion tree structure manner. These screens are downloaded ,~ . ' ' ' ' ~ `
:
7~7 from the system manager for storage at the terminal so that they are available for display if and when called for. In operation, if a particu-lar branch of a decision tree is no~ selected by the user, screens asso-ciated with that branch are deleted from terminal memory as needed to make room for new screens. The terminal memory is also con-trolled so that character screen commands are swapped in and out of memory based on their relative priority.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block schematic diagram of an interactive ente~
tainment system in accordance with the present invention applied in a hotel or hospital system environment comprising automatically configurable two-way interactive terminals.
Figure la is a block schematic diagram of system manager 12 of Figure 1.
Figure 2 is a block schematic diagram of a two-way interactive terminal according to the present invention comprising a micropro-cessor, a memory, a character generator, a key pad and a television signal output to an associated television receiver.
Figure 3 is a schematic diagram showing the data types stored within the screen data area of RAM 21~ of Figure 2.
Figure 4 is a schematic diagram showing the data structure of character screen commands stored in RAM 217 of Figure 2.
Figure S is a schematic diagram showing the data struc~ure of the key template shown in Figure ~.
Figure 6 shows a number of exemplary display screens and associated key templates for the in-room checkout feature.
Figure 7a is a block diagram showing the tree structure of a fan~ut type feature.
Figure 7b is a block diagram showing the tree structure of a serial chain type feature.
DETAlLED DESCRIPTION O~ THE PREFERRED EM_ODIMENT
Referring to Figure 1, there is shown a block schematic dia-gram of an interactive entertainment system in accordance with the present invention. The depicted embodiment relates to its application in a hotel or hospital system environment, however, the present ~'' , -- 5 ~ ~7 invention is not so limited, and may be applied in any two-way inter-active entertainment system such as a cable or satellite television entertainment system involving a distribution ne~work comprising trunk lines and feeder cables of optical or coaxial cable. For exam-ple, satellite receiver and decoder 3, cable receiver and descrambler 4, video modulator 5, addressable transmitter receiver 10, locally gen-erated video modulator 11, and system manager 12 may all be located at the location of a cable television system head end. In this example, coaxial cable or optical fiber link 6 can connect the cable television head end to two-way interactive terminals 7, 8 or 9 of the enter~ain-ment system located at individual subscriber premises.
On the other hand, the embodiment of Figure 1 is especially exemplary oI the application of the present invention in a hotel or hospital entertainment system. Transmission link 6, then, may simply comprise a coaxial or optical fiber cable link be~ween an entertain-ment control center and a plurality of terminals, for example, termi-nals ~, 8 or ~ located in rooms of the facility.
In particular, at the system control center, a satellite signal may be received at satellite antenna 2 and then received and decoded at satellite receiver decoder 3 for distribution via modulator 5 over a distribution cable 6 to the interactive terminals 7, 8 or 9 of the pre-sent invention. Additionally, a band of cable television channe~s received over cable facilities 1 are received and, if necessary, descrambled at cable receiver/descrambler 4. The descrambled video signals are then modulated at modulator S for distribution over facili-ties 6 to interactive terminals ~, 8 or 9. If desired, an optional scram-bler may be provided for scrambling premium channel transmissions to interactive terminals ~, 8, or 9. Of course, terminal 7, 8, or 9, then, would comprise descrambler circuitry capable of descrambling the scrambled premium channel transmissions. Such circuitry is not shown in either Figure 1 or 2 but would be preferable in a system involving distribution of signals to remote subscriber locations.
According to the exemplary embodiment of Figure 1, the hotel or hospital location may be connecte~ to other hotels or hospita~s via data link 14. Over data link 14, data may be received via modem 13 ~ - 2~fl7~
at system manager 12. In this manner, the hotel or hospital system manager may maintain current status of all features and all interac-tive terminals of an entertainment system comprising a plurality of hote~s. For example, entertainment schedules may be distributed over the data transmission link from a network control center where the entertainment schedule is composed. System manager 12 comprises a data processing unit and appropriate memory for storing status and features associated with all terminals in the system. System manager 12 also controls the generation of video channels at modulator 11, if necessary, for transmission over facility 6 to the two-way interactive terminals ?, 8 or 9. In particular, modulator 11 comprises the capabil-ity tO generate signals for actuating the display of ~haracter screens at tsrminal locations responsive to the con~rol of the system manager 12 in the event, for example, that terminals are unable to generate the character screens themselves.
The generation of complete screens of characters for transmis-sion to a terminal according to the present invention for display is not required because the terminal (Figure 2) comprises its own character generator 204. Consequently, locally generated video modulator 11 is optional. Instead, system manager 12 generates commands to gener-ate screens, and not the screens themselves, for transmission via addressable transmitter 10 to an interactive terminal according to the present invention. In a ~hybrid~ system comprising terminals having no character generator and terminals according to the present inven-tion, locally generated video modulator 11 would be necessary. The screens generated either at the terminal or by way of modulator 11, for example, may relate to the provision of information to guests or patients a~ut hotel or hospi~al services, respectively.
Also according to Figure 1, system manager 12 controls an addressable transmitter/receiver lO for transmitting addressed com-rnunications which are uniquely addressed to terminals 7, 8 or 9 and receiving communications at random times or in response to polling requests of terminals. The addressable transmitter 10 according to Figure 1 may transmit addressed information on a separate data car rier, for example, at 108 megahertz and receiYe information ;~(31~797 transmitted in a so-called upstream direction from the terminals on another separate data channel at 25 megahertz. In an alternative embodiment, all downstream communications may be transmitted in band or within a particular television channel transmission, for exam-ple, within the horizontal or vertical intervals of transmitted video signals. Consequently, the system manager 12 accomplishes in band signaling by controlling data input into the video signals transmitted via either modulators 5 or 11 (not shown). A separate data carrier for each direction of transmission may be preferred due to the increased data carrying capacity. For upstream transmission, a telephone line or spread spectrum transmission may be employed as an alternative to a separate data channel.
Referring to Figure la, system manager 12 particularly com-prises a processor lQ0, an associated memory, ROM, for storing con-trol algorithms, a read/write mernory, RAM, for storing a plurality of character screens, a display screen 101 and a keyboard 102 for screen design and modification. An optional printer 103 is also provided for printing out room checkout bilLs in a similar manner as would occur at a hotel front desk during checkout.
Besides specifically addressed data communications with the interactive terminals ~, 8 or 9, the system manager may also address communications globally to all interactive termina~s which communi-cations may or may not require a terminal to respond. Such global communications, for example, may be addressed to a global address representing all terminals in the particular hotel system or to a group address representing a group of terminals within the system having a commonality of interest.
Referrillg to Figure 2, there is shown a two-way interactive terminal according to the present invention. The ~erminal is coupled via facility 8 to video modulator 5, addressable transmitter/receiver 10, and locally generated video modulator 11, if provided, as shown in Figure 1.
In particular, a two-way interactive terminal according to the present invention comprises an up/down converter 201 for converting channels received over the facility 6 for display at an associated 2~
television receiver (not shown) or for transmitting data modu!ated to 25 megahertz by data transmitter 203 for transmission over facility 6.
Up/down converter 201 passes data on the separate data carrier at 108 megahertz for demodulation and reception at data receiver 203.
Received television entertainment signals are provided by up/down converter 201 to demodulator 202 which also provides automatic fre-quency control and gain control of up/down converter 201.
Demodulator 202 provides video via on screen character generator 204 to channel 3/4 modulator 205. In this manner, on screen charac-ter generation may appear superimposed upon an incoming video sig-nal or displayed in the îorm of a teletext screen, for example, text on a plain colored background. Also at demodulator 202 the baseband audio channel is transmitted to audio output 211 or via channel modu-lator 205 to the television receiver at radio frequency. In addition, a baseband video output 213 may be provided from on screen character generator 204 at video output jaclc 213.
The interactive terminal of the present invention further com-prises a processor 20S for controlling data transmission and reception at data receiver/transmitter 203. Processor 206 also controJs charac-ter generation at character generator 204 via gate array 207. A~so via gate array 207, the processor 206 controls a key pad 216 which may be directly coupled to the gate array or coupled via infrared or other remote control tras~smission link receiver 208. Random access memory (RAM) 217, provided with backup power by capacitor 21~, stores character screen commands, downloaded feature data and other data received over the data transmission link via data receiver 203 from the system manager responsive to processor 206 control.
The processor 206 also has access to a nonvolatile random access memory 222 and access via gate array 207 to an ou~board read only memory (ROM) 21~. Processor 20~ receives remote control key com-mands from a remote control key pad via infrared or other remote control transmission receiver 208. Processor 206 may also control the operation of a phase lock loop 209 and bandpass filter 210 for control-ling operation of the up/down converter 201.
' -~ ' ' 2~ 7~
g Power is supplied via an alternating current input to power supply 215 which provides, for example, a plus 5 volt and a plus 12 volt DC input to various components of the terminal requiring such power. Furthermore, the alternating current power input to power supply 215 may be provided via a controlled switched outlet 214 to an associated device such as the telev~sion receiver associated with the terminal. The state of the switched outlet 214 is controlled via gate array 207 by processor 206. For example, the switched outlet 21~
may continuously provide power to its associated device or provide power only when an ~on~ button of key pad 216 or a remote control key pad is set to an on condition.
Values inside of boxes or associated with boxes are exemplary of memory sizes, clock rates, or component types. For example, clock 220 for clocking the microprocessor operation may operate at 14.318 megahertz. The clock signal is divided down by gate array 207 for operation of the microprocessor 206 which may be a Motorola MC
6803U4 or for clocking other processes of the terminal. The on screen character generator 204, for example, may be a Mitsubishi M50455 component. RAM 21? may comprise 16 kilobytes of memory and ROM 219 may comprise 32 kilobytes of rnemory.
Referring now to Figures 2-8, the meth~ for controlling stor-age of screen data in RAM 21~ of the interac~ive terminal will now be described. Referring first to Figures 2 and 3, in the preferred embodi-ment, F~AM 217 comprises a screen data area which is divided into a plurality of data blocks. Six da~a blocks are shown in Figure 3, how-ever, in the preferred embodiment, RAM 217 is divided into forty seven (47) such blocks. Each data block is comprised of 292 charac-ters, and may contain any one of three types of data, i.e., header data, communications data and screen data. Data in each data block is uniquely identified by a screen number, which is stored at the beginning of the da~a block, and this screen number also identifies the data ~'type~. In the preferred embodiment, header data have a screen number of 127, screen data have screen numbers in the range of 128-1023, and communications data have screen numbers over 1023.
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A Priority List is also stored in RAM 217 and consists of a plu-rality of pointers to the RAM locations at which the data blocks are stored. These pointers are arranged in order based on the relative priority of data stored within the screen data area, and the Priority List is updated whenever ~he contents of the screen area are changed.
In the preferred embodiment, the Priority List contains forty seven entities which indicate, in priority order, the locations in RAM 217 at which data blocks are stored. Once a data block is stored in RAM 217, its location is never altered, but the data block may be updated with new information or replaced entirely, as will be explained.
Referring again to Figure 3, each of the data types stored in RAM 21~ is assigned a relative priority which is reflected in the orga-nization of the Priority List. Header data is of the highest priority.
Next is communications data followed by screen data.
Screen data may be any one of three types "Special~ Fea-ture Start" and "Other", and is further prioritized according to ~type~.
Screen data is also prioritized within each type according to an assigned priority number in the range from 0 to 7, with 0 being the highest priority and 7 being the lowest priority.
A Special screen is of higher priority than either of the other two screen types, and follows communications data in the priority order. Special screens inclu~e, for example, a screen associated with ~Power Upl~, a ~Stand By" screen, and various other screens which are critical to the operation of the user terminal.
A Feature Start screen is next in the priority order. The Fea-ture Start screen is the first screen of each feature, e.g., room serv-ice, in-room checkout, to be displayed to the user when the feature is selected. A channel map stored in RAM 21~ correlates key pad entered channel numbers with either an EI~ channel frequency to which the ~elevision receiver is to be tune~ or with a unique screen number. The channel map thus correla~es each of the Feature Start screens with a predetermined user en~ered channel number so that the Feature Start screen of a par~icular feature is displayed whenever the user enters the predetermined channel number via key pad 217 (Figure 2). For example, in Figure 6, channel 20, entered via key pad ,~ :
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217, is associated with Feature Start screen 490 oî the in-room check-out feature. Other channel keyboard entries activate the terminal to tune to an EIA (Electronic Industries Association) channel frequency for receiving a color television signal.
The third screen type is ~IOther'l, and ~Other~ screens rank last in the priority order. These screens are, thus, the first to be analyzed for possible replacement to make room for other screens of higher priority or associated with the feature currently being viewed by the user, as will be explained. Once the ''Otherll screen area is exhausted, i.e., when no l'Other~' screen remain in memory which can be removed to make room for incoming screens, the other data types, i.e., Feature Start screens, Special screens, communications data, and header data, are also analyzed in reverse priority order, for possible deletion.
Focusing more specifically on the screen data, the data struc-ture of the character screen commands stored in RAM 217 is shown in Figure 4. Briefly, as shown in the figure, the screen data consist of a screen number in the range of 128-1023 which is used, as explained above, to uniquely identify the particular screen. Also associated with each screen is a priority number in the range from 0-7, with 0 being the highest priority and ~ being the lowest priority; a cannibal bit, which aids in swapping screen commands in and out of memory, as will be explained; a type field which indicates the screen type, i.e., Special, Feature Start, or Other; a channel number indicating the channel of any background video or audio associated with the screen;
an audio field for indicating whether background audio is being used; a feature number field for identifying the feature scenario, i.e., room service, in-room checkout, etc., of which the screen is a part; a time out field for specifying the maximum viewing time of the screen; a key template map for associating a particular key of the key pad with a particular operation to be performed by processor 206; a text field which contains the actual text to be outputted on the television receiver; and an attribute field for defining the screen display charac-teristics, e.g., the color and intensity of the ba~kground, the size of the characters, the character blin~c rate and the like.
I
The key template structure is shown in Figure S, and specifies for a particular key of the key pad the action to be taken, e.g., prefetch a screen, and/or the screen or channel, i.e.~ the g~to screen, to be displayed or tuned, respectively at the user terrninal when the key is depressed. In the preferred embodiment, key pad 216 is a hand-held battery operated unit and comprises a total of 18 keys which may be programrnably defined for each display screen to cause a particular action to be performed and/or to cause a go-to screen to be displayed. The effect of the go-to screen of the key template is to create a decision tree or hierarchical screen structure, in which each character screen command contains one or more pointers from which one or more other screens may be accessed.
An example of the key template is shown in Figure 6 for the in-room checkout feature. As shown in the figure, when the checkout feature is initiated by entering channel 20 on key pad 217, screen 490, which is the Feature Start screen, appears. Screen 490 includes a number of instructions which direct the user to depress the "1" key of key pad 216 to review charges; the 1~2" key to check out; and the ~No~' key to exit the feature. A key template is also associated with screen 490, and correlates each of keys 1, 2 and "No", i.e., the expected user responses, with particular actions. Thus, in the example, key 1 causes screen 491 to be displayed; key 2 causes screen S01 to be displayed;
and ~'Noll causes the video to be brought up.
In addition to directing action at the user terminal, a key tem-plate is also provided, as shown in Figure 6, to direct certain process-ing at the system manager location in accordance with the user depressed key. Thus, in the example, depression of key 1 in screen 490 causes the system manager to process the user request and to transfer room charges to the user terminal for display on scr en 491.
Depression of key 2 causes the system manager to process the total charges for the room, which are displayed on screen 501 and depres-sion of key 3 causes no action at the systesn manager.
Key templates for the user terminal and system manager ar~
similarly a~socia~ed with each of the expected key responses of screens ~91 and 501, as shown in Figure 6.
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There are two basic types of features and, thus, two different types of decision tree structures shown in Figures ~a and 7b. In the ~fan-out" type feature (Figure 7a), ~he key templates, associated with the screens of the feature, direct the flow of screens so that one of a number of screens located one level below the current screen in the tree structure is displayed responsive tO user selection. Once a screen associated with a particular branch of the tree is selected, other screens associated with unselected branches will not be accessed and can, therefore, be considered for deletion, as will be explained. Thus, for example, as shown in Figure 7a, a user viewing screen 60 may directly access any one of screens 71-77, however, once a particular screen, for example, screen 71, is selected, none of screen 72-7~ will thereafter be used. Screens 72-7~ can, therefore, be replaced, as needed, by other screens, for example, screens (not shown) following screen 71 in the tree structure, which are likely to be requested by the user.
In contrast to the fan-out feature, in the serial chain type fea-ture (Figure 7b), the key templates of the a~sociated screens direct the flow of screens so that the user either sequentially progresses from one screen to the next in the chain or SkipS back and forth along the chain. The in-room checkout feature shown in Figure 6 is an example of a serial chain ~ype feature.
Besides the key template, a cannibal bit, shown in Figure 4, is also associated with each screen and is used in controlling the storage of screen data in ~AM 21~. The cannibal bit has a value of either 0 or 1. The normal state of the cannibal bit is 1, but the cannibal bit is configured as 0 in some screen comman~s to ensure that the screen is retained in memory. This is particularly useful in dealing with fea-tures of ~he serial chain type. As will be explained, when it is desired to store a screen comrnand in RAM 21~ and the screen data area is full, proce~or 206 will firs~ try to remove screens of type ~Other~
which belong to a feature other than the feature currently selected.
HOWQVer, if only screens of the current feature e~st in memory, PrO-cessor 206 will scan the list of l'go-~o'l screens for the screen cur-rently being viewed and will delete any screen that is not a direct 7~i~
~'go-to.~ This has the effect of deleting screens associated wi~h unse-lected branches of the decision tree and is effective in fan-out type features to remove unneeded screens. If the current feature is a serial chain type feature, it is desirable to maintain all or most of the screens of the feature in terminal memory. But because many o~
these screens are not directly accessible, i.e., will not be l~go-tosl~ of other screens, some screens may be deleted. To avoid this situation, the cannibal bit is configured as llO'-, which signals processor 206, as will be explained, to retain screens of the same feature in terminal memory without regard to the direct ~go-to~s.~
As will be easily understood, the speed at which the system responds to a user request will largely depend upon whether a particu-lar screen is stored locally or whether there is a need to access the central data base at the system manager location. Storage of all screens locally is impractical because this would require too much local storage. However, access is significantly improved by appropri-ately configuring the local store so that at any given time, the screens most likely to be requested are available in the terminal memory ready for display.
As explained above, when a user desires to activate a particu-lar feature, e.g., in-room checkout, he first enters a predetermined channel number via the terminal keyboard associated with the feature in the channel map. This then causes the first screen of the selected feature to be displaye~ on Ihe television receiver. The user may then follow the instructions on the screen to proceed through a sequence of screens associated with the selectec feature.
In operation, whenever a user initiates a feature or reques~s a particular service by depressing a key of the key pad, processor 206 first d~termines whether the re~ques~ed screen, i.e., either the Fea-ture Start screen or the ~Igo to" screen associated with the depressed key, is present in RAM 21~. If it is, then the screen is accessed for display. If the screen is not present in RAM 21~, processor 206 issues a screen request to the system manager which responds by issuing an ~Add screen" command to processor 206 for the requested screen.
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Aside from requesting a screen from the system manager when the processor derermines that a screen requested by a user does not currently reside in memory, processor 206 may also prefetch screens into memory prior to their actual use. This prefetch function is tied to user viewing so that when a user views a screen, screens directly accessible by it, as defined by key template go-to~s, and not already stored in memory, will be requested. It is also desirable once a user request has been completely serviced and the user is no longer waiting for a screen, e.g., because he is watching television or because he has left the room, to reconfigure terminal memory to an initialized state.
Processor 206 will~ thus9 check a Special screen list maintained in RAM 21~ to determine whether there are Special screens which are not already stored in memory, and if there are, these screens will be requested. The channel map will also be searched to identify the screen numbers of all Feature Start screens, a comparison will be made with those screens existent in terminal memory, and any Fea-ture Start screens not present in memory will also be requested.
The basic mechanism for adding screens to RAM 217 is through the ~Add screen~' command and its companion ~Conditional add screen~ command. The "Add screen~' command is issued by the system manager to processor 206 responsive to a screen request by the user terminal or when ~he system manager has a new screen to add to the configuration. The ~Conditional add~' is issued when the system man-ager wishes to address a screen globally to all of the interactive te~
minals in the system, and may also be used to address a screen to a particular terminal.
In operation, when the ~Add screen" command is issued, pr~
cessor 206 determines whether vacant space is available in RA~ 21~
for storing the incoming screen. If space is available, the new screen is stored in the first empty loca~ion, and the Priority List is updated so that the memory address of the new screen is appropria~ely posi-tioned in the list in accordance with the relative priority of the screen. Otherwise, if the RAM is full, it is necessary to remove screen data from RAM 217, and the algorithm described below is used for this purpose.
In general, the removal method will depend upon the current screen i.e., the screen currently being displayed, and the feature with which it is associated. Thus, all l~Other~ screens, beginning with the screen having the lowest priority as reflected by the Priority List, are first analyzed for possible deletion by checking whether a particular candidate screen is associated with the current feature. Once a screen is found which is not part of the current feature scenario, that screen is replaced by the new screen. If the user is currently watch-ing television, i.e., is not currently requesting any system service, there is no current feature, so that processor 206 will replace the first ~Other~' screen in the Priority List, i.e., the ~'Other~' screen with the lowest priority, with the new screen.
If the user is currently viewing a screen and all of the ~Other~
screens in RAM 217 are associated with the current feature, processur 206 examines the cannibal bit of ~he incoming screen. If the cannibal bit is 1, proce~sor 206 searches the "Other~' screens, again beginning with the screen having the lowest priority, to locate screens not directly accessible from the current screen~ i.e., screens that are not direct "go-to's" of the current screen. If a non-go-to screen is located, that screen is replaced by the incoming screen.
If all of the ~Other~ screens are "go-to" screens of the current screen, or if the cannibal bit is 0, processor 206 will then search the IlFeature Star~" screens and will choose the screen lowest in priority for removal, except thae processor 206 will not remove any screen with a 0 priority and also will not remove the ~Feature star~ screen of the current feature.
If no ~Fea~ure start~ screen is found which can be removed, a similar search is made of the Special screens, and the Special screen having the lowest priority will be removed. Again, no screens of 0 priority will be removed.
If no suitable screen can be found for removal, another search is perf ormed depending upon whether the incoming screen was reques~ed by the user terminal. This will generally mean that the screen is essential for continued operation. Thus, if the new screen is the result of a screen request, processor 206 will replace the lowe~t priority screen in memory, disregarding screens with a 0 priority, with the new screen.
The other mechanism for adding screens to RAM 217 is the Qnditional add screen" command which allows the system manager to address a screen globally to all of the interactive terminals in the system or to a particular terminal. The add command is ~'conditional~
in that each terminal determines whether or not it will accept the new screen and, if the screen is accepted, will make room for the screen in accordance with the algorithm described above.
In determining whether a particular screen will be accepted, processor 206 first determines whether the screen corresponds to, i.e., has a same screen number as, a screen currently residing in mem-ory. If it does, then the old screen is replaced with the new screen data.
If the user is watching television, i.e., is not requesting a sys-tem service, at the time the ~Conditional add~l command is issued, processor 206 will also accept and store all "Feature start~ screens and all ~ISpecial" screens. This ensures that those screens critical to system operation as well as those screens likely to be needed and requested first are available for immediate display.
If, on the other hand, the user is viewing a screen at the time the ~Conditional add~l command is issued, the criteria for accepting the incoming screen are different. In particular, if the terminal is currently waiting for ~his particular screen, the screen will ~e ac~epted. Otherwise, "Special" screens and "Feature start~' screens with a priority of 0 will be accepted, and l~Other~l screens will be accepted orlly if the new screen has the same feature number as the screen currently being viewed and is either a direct "gu-to" of the current screen or has a cannibal bit of 0.
This invention has been described in detail in connection with the preferred embodiment. However, it will be easily understood by those skilled in the ar~ that other variations and modifications can be made within the scope of the invention as defined by the appended claims.
STORAGE CONTROL METHOD AND
APPARATUS FOR AN INTERACTIVE
TELEVISION TERMINAL
This application is a- continuation-in-part of application Serial No. 289,21~, filed December 23, 1988, and entitled ~AutOmatic Inter-active Television Terminal Configurationl~ and is related to U.S.
Application Serial Nos.: , (Attorney Docket No.
25,871), entitled ~Cable Television Transaction Terminal~;
, (Attorney Docket No. 25,872), entitled ~Terminal Authorization Method~; (Attorney Docket No.
25,S74), entitled ~Terminal Polling Method";
(Attorney Docket No. 25,~7~), entitled "Interactive Television Ter-minal with Programmable Bac~ground Audio or Video"; and , (Attorney Docket No. 25,8~8), entitled ~Interactive Room Status/Time Information System", filed concurrently herewith.
TECHNICAL FIELD
This invention relates generally to two-way interactive cable television systems in which entertainment services, information and data signals are provided over cable facilities from a system manager location to a user location, and more particularly to a method and apparatus for controlling the storage of data in local storage at the user location.
BACKGROUND OF THE INVENTION
Two-way interactive cable television systems are known for transmitting entertainment, information and data signals over a cable facility toward a plurality of users. Data may be transmitted and addressed to a particular subscriber over a separate data channel or over a so-called llin-band" data channel. In a downstream direction, addressed control data may represent services authorized tO a partic-ular terminal or control commands to that terminal. In an upstream .
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direction from a terminal to the service provider or system manager location, control data may represent selections made by a user in response to a polling request or at the time of user selection.
In a hotel environment, the s-ystem manager delivers video signals, e.g., television programming, to user terminals located, for example, in various hotel rooms o~er cable lines, and the system man-ager also transmits digital messages to receivers at each room loca-tion. Similarly, information and data generated at each room are transmitted upstream to the system manager via the cable.
It is known in the prior art to provide an interactive terminal at a user location including a local processor for controlling access to a host computer located at the system manager location and a local data store connected to the local processor. Such termina~s also nor-mally consist of a display for displaying messages to the user or details of the transaction being conducted, and a keyboard or remote key pad comprising a number of keys by which the user can enter data and initiate functions.
Typically, a central data storage is provided at the system manager location for storing a complete data base, and a smaller su~
set of that data base is maintained in the local store at the user ter-minal. Because faster response times can be achieved if a requested transaction can be completed without the need for repeatedly access ing the central data base, configuration of the local store becomes an important design consideration. Prior methods of local storage man-agement have been based upon last use or recency of use, and systems are also known in which those items in the data base most frequently re~uested by the user terminals are retained in the local store. These methods have not, however~ been entirely satisfactory, and have not uniformly achieved the desired reduction in response time. Accord-ingly, there is a need for a more efficient technic,ue for choosing data items to be stored in a local storage of an interactive terminal sys~em.
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SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved method of local storage management for an interactive terminal which ensures faster response times and which reduces the need for repeatedly accessing the central data base.
It Is another object of the present invention to provide a method o~ local storage management for an interactive terminal whi~h updates the local store in accordance with the relative priority of data entries.
It is still another object of the present invention to provide a method OI local s~orage management which updates the local store in accordance with the system service requested by the user.
An interactive terminal, according to the present invention, comprises a processor, a local data store connected to the processor, a character generator responsive tO processor control for generating a television signal output to an associated television receiver, a key pad or remote control for inpu~ting information to the processor, and a power supply input.
In a hotel environment, the interactive terminals are located in individual hotel rooms and are coupled, via 2-way RF communica-tions, to a central hotel location, designated as the system manager, where the terminals are accessed by polling for monitoring and ser-vicing the guests~ requests. The local storage capacity of the interac-tive terminal is provided for storing data and a number of character screen commands, accessed from a central data base at the system manager, for use in generating prompting screens displayed on the teleYision receiver. Thust in use, a hotel guest may call for a variety of services, e.g., pay T~7 programs, room service and the like, by ope~
ating the input keys of the key pad to cause a prompting screen to be displayed on the television receiver.
According to the invention, character screen commands are stored at the terminal according to an assigned priority. The stored screen commands also include pointers which are used by the terminal processor to prefetch other screens which follow the current screen in a deci~sion tree structure manner. These screens are downloaded ,~ . ' ' ' ' ~ `
:
7~7 from the system manager for storage at the terminal so that they are available for display if and when called for. In operation, if a particu-lar branch of a decision tree is no~ selected by the user, screens asso-ciated with that branch are deleted from terminal memory as needed to make room for new screens. The terminal memory is also con-trolled so that character screen commands are swapped in and out of memory based on their relative priority.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block schematic diagram of an interactive ente~
tainment system in accordance with the present invention applied in a hotel or hospital system environment comprising automatically configurable two-way interactive terminals.
Figure la is a block schematic diagram of system manager 12 of Figure 1.
Figure 2 is a block schematic diagram of a two-way interactive terminal according to the present invention comprising a micropro-cessor, a memory, a character generator, a key pad and a television signal output to an associated television receiver.
Figure 3 is a schematic diagram showing the data types stored within the screen data area of RAM 21~ of Figure 2.
Figure 4 is a schematic diagram showing the data structure of character screen commands stored in RAM 217 of Figure 2.
Figure S is a schematic diagram showing the data struc~ure of the key template shown in Figure ~.
Figure 6 shows a number of exemplary display screens and associated key templates for the in-room checkout feature.
Figure 7a is a block diagram showing the tree structure of a fan~ut type feature.
Figure 7b is a block diagram showing the tree structure of a serial chain type feature.
DETAlLED DESCRIPTION O~ THE PREFERRED EM_ODIMENT
Referring to Figure 1, there is shown a block schematic dia-gram of an interactive entertainment system in accordance with the present invention. The depicted embodiment relates to its application in a hotel or hospital system environment, however, the present ~'' , -- 5 ~ ~7 invention is not so limited, and may be applied in any two-way inter-active entertainment system such as a cable or satellite television entertainment system involving a distribution ne~work comprising trunk lines and feeder cables of optical or coaxial cable. For exam-ple, satellite receiver and decoder 3, cable receiver and descrambler 4, video modulator 5, addressable transmitter receiver 10, locally gen-erated video modulator 11, and system manager 12 may all be located at the location of a cable television system head end. In this example, coaxial cable or optical fiber link 6 can connect the cable television head end to two-way interactive terminals 7, 8 or 9 of the enter~ain-ment system located at individual subscriber premises.
On the other hand, the embodiment of Figure 1 is especially exemplary oI the application of the present invention in a hotel or hospital entertainment system. Transmission link 6, then, may simply comprise a coaxial or optical fiber cable link be~ween an entertain-ment control center and a plurality of terminals, for example, termi-nals ~, 8 or ~ located in rooms of the facility.
In particular, at the system control center, a satellite signal may be received at satellite antenna 2 and then received and decoded at satellite receiver decoder 3 for distribution via modulator 5 over a distribution cable 6 to the interactive terminals 7, 8 or 9 of the pre-sent invention. Additionally, a band of cable television channe~s received over cable facilities 1 are received and, if necessary, descrambled at cable receiver/descrambler 4. The descrambled video signals are then modulated at modulator S for distribution over facili-ties 6 to interactive terminals ~, 8 or 9. If desired, an optional scram-bler may be provided for scrambling premium channel transmissions to interactive terminals ~, 8, or 9. Of course, terminal 7, 8, or 9, then, would comprise descrambler circuitry capable of descrambling the scrambled premium channel transmissions. Such circuitry is not shown in either Figure 1 or 2 but would be preferable in a system involving distribution of signals to remote subscriber locations.
According to the exemplary embodiment of Figure 1, the hotel or hospital location may be connecte~ to other hotels or hospita~s via data link 14. Over data link 14, data may be received via modem 13 ~ - 2~fl7~
at system manager 12. In this manner, the hotel or hospital system manager may maintain current status of all features and all interac-tive terminals of an entertainment system comprising a plurality of hote~s. For example, entertainment schedules may be distributed over the data transmission link from a network control center where the entertainment schedule is composed. System manager 12 comprises a data processing unit and appropriate memory for storing status and features associated with all terminals in the system. System manager 12 also controls the generation of video channels at modulator 11, if necessary, for transmission over facility 6 to the two-way interactive terminals ?, 8 or 9. In particular, modulator 11 comprises the capabil-ity tO generate signals for actuating the display of ~haracter screens at tsrminal locations responsive to the con~rol of the system manager 12 in the event, for example, that terminals are unable to generate the character screens themselves.
The generation of complete screens of characters for transmis-sion to a terminal according to the present invention for display is not required because the terminal (Figure 2) comprises its own character generator 204. Consequently, locally generated video modulator 11 is optional. Instead, system manager 12 generates commands to gener-ate screens, and not the screens themselves, for transmission via addressable transmitter 10 to an interactive terminal according to the present invention. In a ~hybrid~ system comprising terminals having no character generator and terminals according to the present inven-tion, locally generated video modulator 11 would be necessary. The screens generated either at the terminal or by way of modulator 11, for example, may relate to the provision of information to guests or patients a~ut hotel or hospi~al services, respectively.
Also according to Figure 1, system manager 12 controls an addressable transmitter/receiver lO for transmitting addressed com-rnunications which are uniquely addressed to terminals 7, 8 or 9 and receiving communications at random times or in response to polling requests of terminals. The addressable transmitter 10 according to Figure 1 may transmit addressed information on a separate data car rier, for example, at 108 megahertz and receiYe information ;~(31~797 transmitted in a so-called upstream direction from the terminals on another separate data channel at 25 megahertz. In an alternative embodiment, all downstream communications may be transmitted in band or within a particular television channel transmission, for exam-ple, within the horizontal or vertical intervals of transmitted video signals. Consequently, the system manager 12 accomplishes in band signaling by controlling data input into the video signals transmitted via either modulators 5 or 11 (not shown). A separate data carrier for each direction of transmission may be preferred due to the increased data carrying capacity. For upstream transmission, a telephone line or spread spectrum transmission may be employed as an alternative to a separate data channel.
Referring to Figure la, system manager 12 particularly com-prises a processor lQ0, an associated memory, ROM, for storing con-trol algorithms, a read/write mernory, RAM, for storing a plurality of character screens, a display screen 101 and a keyboard 102 for screen design and modification. An optional printer 103 is also provided for printing out room checkout bilLs in a similar manner as would occur at a hotel front desk during checkout.
Besides specifically addressed data communications with the interactive terminals ~, 8 or 9, the system manager may also address communications globally to all interactive termina~s which communi-cations may or may not require a terminal to respond. Such global communications, for example, may be addressed to a global address representing all terminals in the particular hotel system or to a group address representing a group of terminals within the system having a commonality of interest.
Referrillg to Figure 2, there is shown a two-way interactive terminal according to the present invention. The ~erminal is coupled via facility 8 to video modulator 5, addressable transmitter/receiver 10, and locally generated video modulator 11, if provided, as shown in Figure 1.
In particular, a two-way interactive terminal according to the present invention comprises an up/down converter 201 for converting channels received over the facility 6 for display at an associated 2~
television receiver (not shown) or for transmitting data modu!ated to 25 megahertz by data transmitter 203 for transmission over facility 6.
Up/down converter 201 passes data on the separate data carrier at 108 megahertz for demodulation and reception at data receiver 203.
Received television entertainment signals are provided by up/down converter 201 to demodulator 202 which also provides automatic fre-quency control and gain control of up/down converter 201.
Demodulator 202 provides video via on screen character generator 204 to channel 3/4 modulator 205. In this manner, on screen charac-ter generation may appear superimposed upon an incoming video sig-nal or displayed in the îorm of a teletext screen, for example, text on a plain colored background. Also at demodulator 202 the baseband audio channel is transmitted to audio output 211 or via channel modu-lator 205 to the television receiver at radio frequency. In addition, a baseband video output 213 may be provided from on screen character generator 204 at video output jaclc 213.
The interactive terminal of the present invention further com-prises a processor 20S for controlling data transmission and reception at data receiver/transmitter 203. Processor 206 also controJs charac-ter generation at character generator 204 via gate array 207. A~so via gate array 207, the processor 206 controls a key pad 216 which may be directly coupled to the gate array or coupled via infrared or other remote control tras~smission link receiver 208. Random access memory (RAM) 217, provided with backup power by capacitor 21~, stores character screen commands, downloaded feature data and other data received over the data transmission link via data receiver 203 from the system manager responsive to processor 206 control.
The processor 206 also has access to a nonvolatile random access memory 222 and access via gate array 207 to an ou~board read only memory (ROM) 21~. Processor 20~ receives remote control key com-mands from a remote control key pad via infrared or other remote control transmission receiver 208. Processor 206 may also control the operation of a phase lock loop 209 and bandpass filter 210 for control-ling operation of the up/down converter 201.
' -~ ' ' 2~ 7~
g Power is supplied via an alternating current input to power supply 215 which provides, for example, a plus 5 volt and a plus 12 volt DC input to various components of the terminal requiring such power. Furthermore, the alternating current power input to power supply 215 may be provided via a controlled switched outlet 214 to an associated device such as the telev~sion receiver associated with the terminal. The state of the switched outlet 214 is controlled via gate array 207 by processor 206. For example, the switched outlet 21~
may continuously provide power to its associated device or provide power only when an ~on~ button of key pad 216 or a remote control key pad is set to an on condition.
Values inside of boxes or associated with boxes are exemplary of memory sizes, clock rates, or component types. For example, clock 220 for clocking the microprocessor operation may operate at 14.318 megahertz. The clock signal is divided down by gate array 207 for operation of the microprocessor 206 which may be a Motorola MC
6803U4 or for clocking other processes of the terminal. The on screen character generator 204, for example, may be a Mitsubishi M50455 component. RAM 21? may comprise 16 kilobytes of memory and ROM 219 may comprise 32 kilobytes of rnemory.
Referring now to Figures 2-8, the meth~ for controlling stor-age of screen data in RAM 21~ of the interac~ive terminal will now be described. Referring first to Figures 2 and 3, in the preferred embodi-ment, F~AM 217 comprises a screen data area which is divided into a plurality of data blocks. Six da~a blocks are shown in Figure 3, how-ever, in the preferred embodiment, RAM 217 is divided into forty seven (47) such blocks. Each data block is comprised of 292 charac-ters, and may contain any one of three types of data, i.e., header data, communications data and screen data. Data in each data block is uniquely identified by a screen number, which is stored at the beginning of the da~a block, and this screen number also identifies the data ~'type~. In the preferred embodiment, header data have a screen number of 127, screen data have screen numbers in the range of 128-1023, and communications data have screen numbers over 1023.
~' , 2~
A Priority List is also stored in RAM 217 and consists of a plu-rality of pointers to the RAM locations at which the data blocks are stored. These pointers are arranged in order based on the relative priority of data stored within the screen data area, and the Priority List is updated whenever ~he contents of the screen area are changed.
In the preferred embodiment, the Priority List contains forty seven entities which indicate, in priority order, the locations in RAM 217 at which data blocks are stored. Once a data block is stored in RAM 217, its location is never altered, but the data block may be updated with new information or replaced entirely, as will be explained.
Referring again to Figure 3, each of the data types stored in RAM 21~ is assigned a relative priority which is reflected in the orga-nization of the Priority List. Header data is of the highest priority.
Next is communications data followed by screen data.
Screen data may be any one of three types "Special~ Fea-ture Start" and "Other", and is further prioritized according to ~type~.
Screen data is also prioritized within each type according to an assigned priority number in the range from 0 to 7, with 0 being the highest priority and 7 being the lowest priority.
A Special screen is of higher priority than either of the other two screen types, and follows communications data in the priority order. Special screens inclu~e, for example, a screen associated with ~Power Upl~, a ~Stand By" screen, and various other screens which are critical to the operation of the user terminal.
A Feature Start screen is next in the priority order. The Fea-ture Start screen is the first screen of each feature, e.g., room serv-ice, in-room checkout, to be displayed to the user when the feature is selected. A channel map stored in RAM 21~ correlates key pad entered channel numbers with either an EI~ channel frequency to which the ~elevision receiver is to be tune~ or with a unique screen number. The channel map thus correla~es each of the Feature Start screens with a predetermined user en~ered channel number so that the Feature Start screen of a par~icular feature is displayed whenever the user enters the predetermined channel number via key pad 217 (Figure 2). For example, in Figure 6, channel 20, entered via key pad ,~ :
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217, is associated with Feature Start screen 490 oî the in-room check-out feature. Other channel keyboard entries activate the terminal to tune to an EIA (Electronic Industries Association) channel frequency for receiving a color television signal.
The third screen type is ~IOther'l, and ~Other~ screens rank last in the priority order. These screens are, thus, the first to be analyzed for possible replacement to make room for other screens of higher priority or associated with the feature currently being viewed by the user, as will be explained. Once the ''Otherll screen area is exhausted, i.e., when no l'Other~' screen remain in memory which can be removed to make room for incoming screens, the other data types, i.e., Feature Start screens, Special screens, communications data, and header data, are also analyzed in reverse priority order, for possible deletion.
Focusing more specifically on the screen data, the data struc-ture of the character screen commands stored in RAM 217 is shown in Figure 4. Briefly, as shown in the figure, the screen data consist of a screen number in the range of 128-1023 which is used, as explained above, to uniquely identify the particular screen. Also associated with each screen is a priority number in the range from 0-7, with 0 being the highest priority and ~ being the lowest priority; a cannibal bit, which aids in swapping screen commands in and out of memory, as will be explained; a type field which indicates the screen type, i.e., Special, Feature Start, or Other; a channel number indicating the channel of any background video or audio associated with the screen;
an audio field for indicating whether background audio is being used; a feature number field for identifying the feature scenario, i.e., room service, in-room checkout, etc., of which the screen is a part; a time out field for specifying the maximum viewing time of the screen; a key template map for associating a particular key of the key pad with a particular operation to be performed by processor 206; a text field which contains the actual text to be outputted on the television receiver; and an attribute field for defining the screen display charac-teristics, e.g., the color and intensity of the ba~kground, the size of the characters, the character blin~c rate and the like.
I
The key template structure is shown in Figure S, and specifies for a particular key of the key pad the action to be taken, e.g., prefetch a screen, and/or the screen or channel, i.e.~ the g~to screen, to be displayed or tuned, respectively at the user terrninal when the key is depressed. In the preferred embodiment, key pad 216 is a hand-held battery operated unit and comprises a total of 18 keys which may be programrnably defined for each display screen to cause a particular action to be performed and/or to cause a go-to screen to be displayed. The effect of the go-to screen of the key template is to create a decision tree or hierarchical screen structure, in which each character screen command contains one or more pointers from which one or more other screens may be accessed.
An example of the key template is shown in Figure 6 for the in-room checkout feature. As shown in the figure, when the checkout feature is initiated by entering channel 20 on key pad 217, screen 490, which is the Feature Start screen, appears. Screen 490 includes a number of instructions which direct the user to depress the "1" key of key pad 216 to review charges; the 1~2" key to check out; and the ~No~' key to exit the feature. A key template is also associated with screen 490, and correlates each of keys 1, 2 and "No", i.e., the expected user responses, with particular actions. Thus, in the example, key 1 causes screen 491 to be displayed; key 2 causes screen S01 to be displayed;
and ~'Noll causes the video to be brought up.
In addition to directing action at the user terminal, a key tem-plate is also provided, as shown in Figure 6, to direct certain process-ing at the system manager location in accordance with the user depressed key. Thus, in the example, depression of key 1 in screen 490 causes the system manager to process the user request and to transfer room charges to the user terminal for display on scr en 491.
Depression of key 2 causes the system manager to process the total charges for the room, which are displayed on screen 501 and depres-sion of key 3 causes no action at the systesn manager.
Key templates for the user terminal and system manager ar~
similarly a~socia~ed with each of the expected key responses of screens ~91 and 501, as shown in Figure 6.
7~'~
There are two basic types of features and, thus, two different types of decision tree structures shown in Figures ~a and 7b. In the ~fan-out" type feature (Figure 7a), ~he key templates, associated with the screens of the feature, direct the flow of screens so that one of a number of screens located one level below the current screen in the tree structure is displayed responsive tO user selection. Once a screen associated with a particular branch of the tree is selected, other screens associated with unselected branches will not be accessed and can, therefore, be considered for deletion, as will be explained. Thus, for example, as shown in Figure 7a, a user viewing screen 60 may directly access any one of screens 71-77, however, once a particular screen, for example, screen 71, is selected, none of screen 72-7~ will thereafter be used. Screens 72-7~ can, therefore, be replaced, as needed, by other screens, for example, screens (not shown) following screen 71 in the tree structure, which are likely to be requested by the user.
In contrast to the fan-out feature, in the serial chain type fea-ture (Figure 7b), the key templates of the a~sociated screens direct the flow of screens so that the user either sequentially progresses from one screen to the next in the chain or SkipS back and forth along the chain. The in-room checkout feature shown in Figure 6 is an example of a serial chain ~ype feature.
Besides the key template, a cannibal bit, shown in Figure 4, is also associated with each screen and is used in controlling the storage of screen data in ~AM 21~. The cannibal bit has a value of either 0 or 1. The normal state of the cannibal bit is 1, but the cannibal bit is configured as 0 in some screen comman~s to ensure that the screen is retained in memory. This is particularly useful in dealing with fea-tures of ~he serial chain type. As will be explained, when it is desired to store a screen comrnand in RAM 21~ and the screen data area is full, proce~or 206 will firs~ try to remove screens of type ~Other~
which belong to a feature other than the feature currently selected.
HOWQVer, if only screens of the current feature e~st in memory, PrO-cessor 206 will scan the list of l'go-~o'l screens for the screen cur-rently being viewed and will delete any screen that is not a direct 7~i~
~'go-to.~ This has the effect of deleting screens associated wi~h unse-lected branches of the decision tree and is effective in fan-out type features to remove unneeded screens. If the current feature is a serial chain type feature, it is desirable to maintain all or most of the screens of the feature in terminal memory. But because many o~
these screens are not directly accessible, i.e., will not be l~go-tosl~ of other screens, some screens may be deleted. To avoid this situation, the cannibal bit is configured as llO'-, which signals processor 206, as will be explained, to retain screens of the same feature in terminal memory without regard to the direct ~go-to~s.~
As will be easily understood, the speed at which the system responds to a user request will largely depend upon whether a particu-lar screen is stored locally or whether there is a need to access the central data base at the system manager location. Storage of all screens locally is impractical because this would require too much local storage. However, access is significantly improved by appropri-ately configuring the local store so that at any given time, the screens most likely to be requested are available in the terminal memory ready for display.
As explained above, when a user desires to activate a particu-lar feature, e.g., in-room checkout, he first enters a predetermined channel number via the terminal keyboard associated with the feature in the channel map. This then causes the first screen of the selected feature to be displaye~ on Ihe television receiver. The user may then follow the instructions on the screen to proceed through a sequence of screens associated with the selectec feature.
In operation, whenever a user initiates a feature or reques~s a particular service by depressing a key of the key pad, processor 206 first d~termines whether the re~ques~ed screen, i.e., either the Fea-ture Start screen or the ~Igo to" screen associated with the depressed key, is present in RAM 21~. If it is, then the screen is accessed for display. If the screen is not present in RAM 21~, processor 206 issues a screen request to the system manager which responds by issuing an ~Add screen" command to processor 206 for the requested screen.
7~
Aside from requesting a screen from the system manager when the processor derermines that a screen requested by a user does not currently reside in memory, processor 206 may also prefetch screens into memory prior to their actual use. This prefetch function is tied to user viewing so that when a user views a screen, screens directly accessible by it, as defined by key template go-to~s, and not already stored in memory, will be requested. It is also desirable once a user request has been completely serviced and the user is no longer waiting for a screen, e.g., because he is watching television or because he has left the room, to reconfigure terminal memory to an initialized state.
Processor 206 will~ thus9 check a Special screen list maintained in RAM 21~ to determine whether there are Special screens which are not already stored in memory, and if there are, these screens will be requested. The channel map will also be searched to identify the screen numbers of all Feature Start screens, a comparison will be made with those screens existent in terminal memory, and any Fea-ture Start screens not present in memory will also be requested.
The basic mechanism for adding screens to RAM 217 is through the ~Add screen~' command and its companion ~Conditional add screen~ command. The "Add screen~' command is issued by the system manager to processor 206 responsive to a screen request by the user terminal or when ~he system manager has a new screen to add to the configuration. The ~Conditional add~' is issued when the system man-ager wishes to address a screen globally to all of the interactive te~
minals in the system, and may also be used to address a screen to a particular terminal.
In operation, when the ~Add screen" command is issued, pr~
cessor 206 determines whether vacant space is available in RA~ 21~
for storing the incoming screen. If space is available, the new screen is stored in the first empty loca~ion, and the Priority List is updated so that the memory address of the new screen is appropria~ely posi-tioned in the list in accordance with the relative priority of the screen. Otherwise, if the RAM is full, it is necessary to remove screen data from RAM 217, and the algorithm described below is used for this purpose.
In general, the removal method will depend upon the current screen i.e., the screen currently being displayed, and the feature with which it is associated. Thus, all l~Other~ screens, beginning with the screen having the lowest priority as reflected by the Priority List, are first analyzed for possible deletion by checking whether a particular candidate screen is associated with the current feature. Once a screen is found which is not part of the current feature scenario, that screen is replaced by the new screen. If the user is currently watch-ing television, i.e., is not currently requesting any system service, there is no current feature, so that processor 206 will replace the first ~Other~' screen in the Priority List, i.e., the ~'Other~' screen with the lowest priority, with the new screen.
If the user is currently viewing a screen and all of the ~Other~
screens in RAM 217 are associated with the current feature, processur 206 examines the cannibal bit of ~he incoming screen. If the cannibal bit is 1, proce~sor 206 searches the "Other~' screens, again beginning with the screen having the lowest priority, to locate screens not directly accessible from the current screen~ i.e., screens that are not direct "go-to's" of the current screen. If a non-go-to screen is located, that screen is replaced by the incoming screen.
If all of the ~Other~ screens are "go-to" screens of the current screen, or if the cannibal bit is 0, processor 206 will then search the IlFeature Star~" screens and will choose the screen lowest in priority for removal, except thae processor 206 will not remove any screen with a 0 priority and also will not remove the ~Feature star~ screen of the current feature.
If no ~Fea~ure start~ screen is found which can be removed, a similar search is made of the Special screens, and the Special screen having the lowest priority will be removed. Again, no screens of 0 priority will be removed.
If no suitable screen can be found for removal, another search is perf ormed depending upon whether the incoming screen was reques~ed by the user terminal. This will generally mean that the screen is essential for continued operation. Thus, if the new screen is the result of a screen request, processor 206 will replace the lowe~t priority screen in memory, disregarding screens with a 0 priority, with the new screen.
The other mechanism for adding screens to RAM 217 is the Qnditional add screen" command which allows the system manager to address a screen globally to all of the interactive terminals in the system or to a particular terminal. The add command is ~'conditional~
in that each terminal determines whether or not it will accept the new screen and, if the screen is accepted, will make room for the screen in accordance with the algorithm described above.
In determining whether a particular screen will be accepted, processor 206 first determines whether the screen corresponds to, i.e., has a same screen number as, a screen currently residing in mem-ory. If it does, then the old screen is replaced with the new screen data.
If the user is watching television, i.e., is not requesting a sys-tem service, at the time the ~Conditional add~l command is issued, processor 206 will also accept and store all "Feature start~ screens and all ~ISpecial" screens. This ensures that those screens critical to system operation as well as those screens likely to be needed and requested first are available for immediate display.
If, on the other hand, the user is viewing a screen at the time the ~Conditional add~l command is issued, the criteria for accepting the incoming screen are different. In particular, if the terminal is currently waiting for ~his particular screen, the screen will ~e ac~epted. Otherwise, "Special" screens and "Feature start~' screens with a priority of 0 will be accepted, and l~Other~l screens will be accepted orlly if the new screen has the same feature number as the screen currently being viewed and is either a direct "gu-to" of the current screen or has a cannibal bit of 0.
This invention has been described in detail in connection with the preferred embodiment. However, it will be easily understood by those skilled in the ar~ that other variations and modifications can be made within the scope of the invention as defined by the appended claims.
Claims (14)
1. A two-way interactive terminal system comprising:
a host data processor;
a central data store controlled by the host processor for storing a central data base, said central data base comprising a plural-ity of data items, each of said data items having a preassigned priority value; and at least one local terminal subsystem connectable to the host processor for accessing data items stored in the central data base, said terminal subsystem comprising:
a local processor for controlling access to the host processor;
memory means controlled by the local processor and comprising a first memory area for storing data items accessed from the central data base;
means operable when the first memory area has no vacant space for storing a newly accessed data item to locate a data item in said first memory area for deletion based on the relative pri-ority values of the data items; and means responsive to said locating means to delete the data item located by the locating means to create space in the first memory area for the newly accessed item.
a host data processor;
a central data store controlled by the host processor for storing a central data base, said central data base comprising a plural-ity of data items, each of said data items having a preassigned priority value; and at least one local terminal subsystem connectable to the host processor for accessing data items stored in the central data base, said terminal subsystem comprising:
a local processor for controlling access to the host processor;
memory means controlled by the local processor and comprising a first memory area for storing data items accessed from the central data base;
means operable when the first memory area has no vacant space for storing a newly accessed data item to locate a data item in said first memory area for deletion based on the relative pri-ority values of the data items; and means responsive to said locating means to delete the data item located by the locating means to create space in the first memory area for the newly accessed item.
2. The terminal system of claim 1 wherein said memory means further comprises a second memory area for storing a direc-tory entry for each of said data items stored in the first memory area, said directory entries specifying the memory address in said first memory area of each of the data items and being stored in said second memory area in sorted order according to the relative priority of the data items.
3. The terminal system of claim 2 wherein said local ter-minal subsystem further comprises sorting means for updating and sorting said directory entries whenever the contents of the first mem-ory area are changed.
4. The terminal system of claim 2 wherein said locating means locates a data item to be deleted by accessing said second memory area.
5. The terminal subsystem of claim 1 further comprising a keyboard for inputting information to the local processor.
6. The terminal subsystem of claim 5 wherein said local processor separately activates a plurality of system features respon-sive to the actuation of predetermined keys of the keyboard.
7. The terminal system of claim 6 wherein the data items stored in the first memory area comprise a plurality of character screen commands and wherein said terminal subsystem further com-prises a character generator, responsive to a character screen com-mand from the local processor, for generating a character display screen for display on an associated television receiver.
8. The terminal system of claim 7 wherein said memory means further comprises a third memory area for storing a channel map containing a plurality of entries, the entries identifying for each of the system features a predetermined keyboard key and a predeter-mined character screen command, the character screen command being accessed by said local processor for display on the television receiver responsive to actuation of the predetermined key.
9. The terminal system of claim 7 wherein each of the character screen commands has a preassigned feature number corre-sponding to one of said plurality of system features.
10. The terminal system of claim 9 wherein if said first memory area is full and said local processor has activated a system feature, said locating means locates a data item in said first memory area for deletion having the lowest relative priority value and having a feature number different than the activated feature.
11. The terminal system of claim 9 wherein said character generator, responsive to at least one of said character screen com-mands, generates a character display screen requiring a keyboard response, and wherein said at least one of said character screen com-mands includes a pointer specifying another character screen command to be accessed by the local processor responsive to the key-board response.
12. The terminal system of claim 11 wherein when the fea-ture of said at least one character screen command has been acti-vated, if no space is available in said first memory area for storing a newly accessed item and if all of the character screens stored in said first memory area contain a feature number which is the same as the feature number of said at least one character screen command, said locating means locates a data item in said first memory area, other than said another character screen command, having the lowest rela-tive priority value.
13. The terminal system of claim 9 wherein a cannibal bit is associated with each of said character screen commands, and wherein if no space is available in said first memory area for storing a newly accessed item and the local processor has activated a system feature, the local processor allows deletion of a character screen command having a feature number corresponding to the activated feature if the cannibal bit of the newly accessed item is 1 and the local processor inhibits deletion of a character screen command having a feature number corresponding to the activated feature if the cannibal bit of the newly accessed item is 0.
14. In a two-way interactive terminal system comprising a host data processor, a central data store controlled by the host pro-cessor for storing a central data base, said data base comprising a plurality of data items, each of the data items having a preassigned priority number, at least one local terminal subsystem connectable to the host processor for accessing data items stored in the central data base, said terminal subsystem comprising a local processor for con-trolling access to the host processor and memory means controlled by the local processor comprising a first memory area for storing data items accessed from the central data base, a method for controlling the storage of data items in said first memory area comprising the steps of:
determining whether said first memory means contains vacant space for storing a data item accessed from said central data base;
storing said newly accessed data item in said first mem-ory area if vacant space exists in the first memory area; and locating a data item in said first memory area for dele-tion based on the relative priority values of the data items and replac-ing the located data item with the newly accessed data item when no vacant space exists in the first memory area.
determining whether said first memory means contains vacant space for storing a data item accessed from said central data base;
storing said newly accessed data item in said first mem-ory area if vacant space exists in the first memory area; and locating a data item in said first memory area for dele-tion based on the relative priority values of the data items and replac-ing the located data item with the newly accessed data item when no vacant space exists in the first memory area.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34298789A | 1989-04-20 | 1989-04-20 | |
| US342,987 | 1989-04-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2014797A1 true CA2014797A1 (en) | 1990-10-20 |
Family
ID=23344187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002014797A Abandoned CA2014797A1 (en) | 1989-04-20 | 1990-04-18 | Storage control method and apparatus for an interactive television terminal |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN1047949A (en) |
| AU (1) | AU5557090A (en) |
| CA (1) | CA2014797A1 (en) |
| WO (1) | WO1990013086A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE500673C2 (en) * | 1991-11-27 | 1994-08-08 | Icl Systems Ab | Procedure and arrangement for establishing a simplified dialogue between a central computer unit and at least one user unit |
| NL9301048A (en) * | 1993-06-16 | 1995-01-16 | Nwt Datawave B V | Interactive television system. |
| EP0668649B1 (en) * | 1994-02-22 | 1999-05-06 | Koninklijke Philips Electronics N.V. | Method of transmitting picture data from a transmitter to a selected receiver |
| US5630757A (en) * | 1994-11-29 | 1997-05-20 | Net Game Limited | Real-time multi-user game communication system using existing cable television infrastructure |
| ITRM950516A1 (en) * | 1995-07-27 | 1997-01-27 | Dal Pane Stefano | MULTIMEDIA TELEMATIC AND SATELLITE SYSTEM FOR FINANCIAL, ECONOMIC AND TAX TRANSACTIONS AND VALIDATION BETWEEN USERS AND SERVICES |
| US5903816A (en) * | 1996-07-01 | 1999-05-11 | Thomson Consumer Electronics, Inc. | Interactive television system and method for displaying web-like stills with hyperlinks |
| EP0827340A3 (en) * | 1996-08-30 | 1999-10-06 | Matsushita Electric Industrial Co., Ltd. | Terminal apparatus and method for achieving interactive operations |
| US6029068A (en) * | 1996-08-30 | 2000-02-22 | Casio Computer Co., Ltd. | Database system, data management system and communication terminal |
| CN102497591B (en) * | 2011-11-11 | 2015-02-18 | 青岛海信移动通信技术股份有限公司 | Terminal and method for realizing wireless screen transmission between terminal and TV |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3906457A (en) * | 1974-02-15 | 1975-09-16 | Victor Comptometer Corp | Display system for an electronic business machine |
| NL7510904A (en) * | 1975-09-17 | 1977-03-21 | Philips Nv | WORD GROUP PRIORITY DEVELOPMENT. |
| GB8502001D0 (en) * | 1985-01-26 | 1985-02-27 | Thorn Emi Ferguson | Teletext units |
-
1990
- 1990-04-18 CA CA002014797A patent/CA2014797A1/en not_active Abandoned
- 1990-04-19 WO PCT/US1990/002034 patent/WO1990013086A1/en unknown
- 1990-04-19 AU AU55570/90A patent/AU5557090A/en not_active Abandoned
- 1990-04-20 CN CN90103914A patent/CN1047949A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU5557090A (en) | 1990-11-16 |
| CN1047949A (en) | 1990-12-19 |
| WO1990013086A1 (en) | 1990-11-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19980420 |