Auxiliary device control for a subscriber terminal

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The invention pertains generally to a subscriber terminal for CATV or other subscription television systems and is more particularly directed to a method and an apparatus for controlling and communicating with peripheral devices from a subscriber terminal.

The subscriber terminal, more commonly known as a set top terminal, is an integral component of subscription television systems. These subscription television systems can be cable television (CATV) systems, SMATV systems, multi-point, multi-distribution (MMDS) systems, or direct-to-home (DTH) systems. The subscriber terminals have conventionally provided the functions of tuning particular channels of the subscription system which are outside the subscriber's television receiver capability. Further, they provide conditional access to the particular subscription service through authorization codes and in many services provide tiering or authorization of particular channels of the service by descrambling or decoding.

More recently, the subscriber terminal has become user friendly by providing an interactive, on-screen display and other functions that allow the subscriber to manipulate the subscription service and his television receiver in additional ways. These features include such things as volume control, pay-per-view event confirmation, favorite channel listings, sleep timer features, viewing channel identification, parental control capability, program timers for recording VCR programs, and other types of consumer friendly operational features.

In addition, some of the on screen features found in newer television receivers can be provided for older television receivers by the subscription terminal. Modern subscription terminals are remotely controlled and provide this capability to the older television receiver. For example, channel identity, mute and remote volume control can be accomplished by the subscriber terminal under remote control making the television receiver appear to have these capabilities.

An advantageous example of a subscriber terminal with these advanced consumer features is the 8600 model series of subscriber terminals manufactured by Scientific-Atlanta, Inc. of Norcross, Ga.

Even with the advance in the user friendly features of such subscriber terminals, there have been some inconveniences in interfacing with other consumer devices, such as VCRs and television receivers, because of the incompatibilities in tuning capability and operation. For example, if a subscriber wants to automatically record a program on his VCR and that program is a premium event (it may have to be descrambled in the subscriber terminal), he must not only set the subscriber terminal program timer, but must also set the VCR program timer to ensure that it will be on and tuned to channel 3/4 which is the normal output of the terminal. To program both of these timers, the subscriber must after selecting the program event translate the event time and date into the interface language of each particular piece of equipment that he is using. While both the subscriber terminal and VCR may have user friendly interfaces to assist in the process, they generally will be quite different and cause considerable confusion for the subscriber.

Recently, there has been a service to assist in automatically programming a VCR which consists of a device to decode certain program event codes. These program event codes can be printed in TV program listings, such as in the newspapers or any of the TV program listing services. The subscriber selects a program from the listing and inputs the associated program event code to the VCR control device which translates the code into a date and time for the occurrence of the program. The device then generates infrared (IR) control commands to a VCR to turn the recorder on and off at the proper times.

Presently, this device does not interface seamlessly with cable television subscription services. If the subscriber connects the VCR through a subscriber terminal because he wants to view a scrambled event, the terminal will cause some inconvenience with this device in that its program timer must still be programmed with the date and time of the program event, but more importantly the channel to be tuned by the VCR must be the output of the terminal, such as channels 3/4 for NTSC. If the subscriber connects the VCR directly to the cable with this device, he can not record premium events and must determine whether the TV program listing from which he has taken the program event code has the same channel line up as his subscription service and must ensure that his VCR can tune that channel.

Therefore, it would be quite advantageous to provide a single subscriber equipment configuration which would seamlessly and easily program both the subscriber terminal and the VCR with a program event code. It would also be of advantage for the subscriber terminal to recognize programming sources and be able to translate these into the specific channel frequencies which a local cable system has assigned to them.

SUMMARY OF THE INVENTION

Therefore, it is an object of the invention to provide a peripheral communications and control interface for an auxiliary device connected to a subscriber terminal.

It is another object of the invention to provide an infrared (IR) peripheral controller as an auxiliary device which communicates with and is controlled by the peripheral interface.

It is still another object of the invention to provide control and communications between the subscriber terminal and the IR peripheral controller to control one or more types of VCRs.

Yet another object of the invention is to provide an apparatus for the automatic recording of a program event based on a program event code input to the subscriber terminal from an associated television program listing.

Accordingly, the invention provides a subscriber terminal for a subscription television service which includes a communications and control interface for auxiliary devices. The interface preferably comprises a four wire ribbon cable which provides a serial transmit line, a serial receive line and ground for bidirectional asynchronous digital communications. The fourth line is a power supply line which will source current from the subscriber terminal to an auxiliary device without an internal power supply.

Data, status and control transactions are defined for the communications and control interface including command transactions initiated from the subscriber terminal and reply transactions from the auxiliary devices. An auxiliary device which can be controlled in this manner is an IR peripheral controller which receives communications from the subscriber terminal and converts them to IR transmissions which can control any number of peripheral devices.

In an illustrated implementation, the interface and IR peripheral controller can be utilized in an apparatus for automatically recording a program event, whether it is scrambled or not. The system includes the subscriber terminal, the IR peripheral controller, a television receiver and a recording device, such as a video cassette recorder. A series of data, status and control transactions are defined between the subscriber terminal and the IR peripheral controller to implement this function.

In one transaction, the subscriber terminal sends the necessary data and control information to the IR peripheral controller to allow the controller to determine which specific VCR it is controlling. As the brands of VCRs (and number of models within a brand) proliferate, this feature allows a facile method of configuring the IR peripheral controller for any particular VCR. Because this function is accomplished with the assistance of the on screen display of the subscriber terminal, the feature permits the subscriber to communicate with a single user friendly interface for configuration.

A second transaction provides control commands to the IR peripheral controller to start and stop the VCR. The IR controller decodes these commands and translates them into the IR transmissions necessary to cause these functions in the VCR. With this feature, the conventional program timers of the subscriber terminal can be used to accomplish automatic recording of the program event. This feature is also assisted with the on screen display of the subscriber terminal so that the subscriber may communicate with a single user friendly interface.

As an additional feature, the system includes an apparatus for automatically recording a program event by means of a program event code which has been selected by the subscriber from an associated television program listing. The program event code which is a coded indication of the start time, duration of the event, and program source is input to the subscriber terminal. The program event code is then translated, either by the subscriber terminal, by the IR controller, or partially by each, into data which can be input to one of the program timers of the subscriber terminal.

Preferably, a third transaction is defined to translate the program event code into time, date, program length, and program source in the IR peripheral controller. This is accomplished by passing the program event code to the IR controller and receiving a reply containing the necessary information. This information is then loaded into one of the program timers of the subscriber terminal. When the time in the program timer elapses, the VCR is controlled to record the event and then stop.

The subscriber terminal includes a channel map which associates program sources with local cable channel numbers. The IR peripheral controller may also have a similar channel map which is programmable. A member of alternative embodiments are possible where, if the peripheral controller does not have a channel map, then a translation of the program source to the local cable channel by the subscriber terminal will take place before the information is stored in a program timer. If the IR peripheral controller has a programmable channel map, then the controller can return the local channel number instead of the program source. As a final embodiment, a transaction is defined to download the IR controller channel map with the channel map of the subscriber terminal so that the correct channel number is returned.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and aspects of the invention will be more clearly understood and better described if the following detailed description is read in conjunction with the appended drawings wherein:

FIG. 1 is a system block diagram of a subscription television system of the CATV type which includes a multiplicity of subscriber terminals;

FIG. 2 is a detailed block diagram of one of the subscriber terminals of the system illustrated in FIG. 1;

FIG. 3 is a pictorial representation of the key functions of the remote control of the subscriber interface to the subscriber terminal illustrated in FIG. 2;

FIG. 4 is a system block diagram of a peripheral communications and control interface between the subscriber terminal and a plurality of auxiliary devices;

FIG. 5 is a detailed electrical schematic diagram of the interface illustrated in FIG. 4;

FIG. 6 is a pictorial representation of the communications protocol among the subscriber terminal and the auxiliary devices which is communicated over the interface illustrated in FIG. 5;

FIG. 7 is a system block diagram of an apparatus for automatically recording a program event on a VCR utilizing the subscriber terminal, the interface, an IR peripheral controller, and a television receiver;

FIGS. 8 and 9 are pictorial representations of a command transaction to control the VCR from the subscriber terminal and the reply transaction from the IR peripheral controller for the apparatus illustrated in FIG. 7;

FIGS. 10 and 11 are pictorial representations of a command transaction to configure the parameters of the IR peripheral controller from the subscriber terminal and the reply transaction from the IR peripheral controller for the apparatus illustrated in FIG. 7;

FIGS. 12 and 13 are pictorial representations of the command to decode a program event code from the subscriber terminal and the reply transaction from the IR peripheral controller to cause the automatic recording of a programmed event based on the event code for the apparatus illustrated in FIG. 7; and

FIG. 14 is a pictorial representation of the command transaction to store the channel map from the subscriber terminal into the channel map space within the IR peripheral controller for the apparatus illustrated in FIG. 7;

FIG. 15 is pictorial representation of the channel map of the IR peripheral controller;

FIGS. 16A-C are a system flow chart of the on screen operations of the subscriber terminal in the system illustrated in FIG. 7 utilizing the interface and transactions illustrated in FIGS. 8, 9, and 12-15; and

FIG. 16D is a system flow chart of the on screen operations of the subscriber terminal in the system illustrated in FIG. 7 utilizing the interface and transactions illustrated in FIGS. 10 and 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A subscription television system of the CATV type is more fully illustrated in FIG. 1. The subscription television system includes a headend 10 and a plurality of subscriber terminals 40, 44 and 48 which are connected over a distribution system 52. As is conventional, the distribution system 52 may include coaxial or optical fiber cable, system amplifiers, line extenders, etc. The headend 10 is under the supervision of a system manager 12 which controls a hardware controller, headend controller 22. A billing computer 11 communicates with the system manager 12 to authorize and transmit transactions to subscribers.

The television or other programming for the subscription system may come from a satellite downlink where it is decoded and demodulated by satellite receivers 18 into a number of channels. Each channel is either applied to a modulator 24 and 30 or a scrambler and modulator 26 and 28 which, under the control of the headend controller 22, remodulates the channels to the frequencies of the local subscription system channel line up. For a premium or restricted channel service (tiered, pay-per-view, or the like), some channels are scrambled by any of the known CATV methods by the scramblers and modulators 26 and 28. While the other channels can be transmitted without conversion. The program channels are then frequency division multiplexed onto the distribution system 52 by an RF combiner 34 as a broadband television signal. The plurality of channels of programming can then be transmitted over the distribution system 52 and supplied to each of the subscriber terminals 40, 44, and 48.

The scramblers and modulators 26 and 28 further may include the function of data insertion for its particular channel. This method of providing the data within the channel signal is generally termed in-band signaling. The data may be applied to any audio portion, video portion or both audio and video portions in combination, or any other portion of the television channel. Many subscription television systems have amplitude modulated data pulses on the audio subcarrier. Further, in other subscription television systems, data may be inserted into the vertical and/or horizontal blanking intervals of the video portion.

The data which is inserted into the television channel in this manner can be conditional access data to globally or locally address and control the subscriber terminals 40, 44 and 48, on screen text data, or other types of information from the headend controller 22. Other data and information, such as electronic program guides and information services, can be inserted into the channels from a data controller 20. The data controller 20 can receive local data or national data from the satellite downlink through the satellite receiver 18.

In addition, data can be transmitted over the distribution system 52 by out-of-band signaling. In this mode, the system manager 12 accesses an addressable transmitter 32 with transactions to transmit this data. The addressable transmitter 32 may be used to modulate a data signal on a frequency not associated with the television programming. The broadband television programming of the cable systems has generally been applied from 50 MHz to 550 MHz and above, while out-of-band signaling systems have been used in non-video portions of these signals, such as at 108.2 MHz with a frequency shift keying modulation technique. These transactions are combined with the broadband television signal at 36 and transmitted to the subscriber terminals 40, 44 and 48.

Transactions in the system are designated as addressed (to a particular subscriber terminal or group of subscriber terminals) and global (to all subscriber terminals). These transactions are in a standardized format which can be sent over any of the communication paths mentioned.

Signaling and data information may also flow in the reverse direction from the subscriber terminals to the headend via a reverse signaling path through the distribution system 52. In one form, the reverse signals are digital biphase shift keying (BPSK) modulated and applied to a frequency below 50 MHz. The signals flow back from the subscriber terminals to an IPPV processor where they are decoded. In addition, any of the subscriber terminals 40, 44 and 48 may include a modem and telephone link 52 to a telephone processor 16 at the headend 10. The information from processors 14 and 16 are directed to the system manager 12, which communicates to the billing computer 11 to obtain authorization and billing information. The reverse signaling system has generally been used for ordering pay-pay-view (PPV) or impulse-pay-per-view (IPPV) events. In the future the reverse signal path may be used for any number of additional interactive services.

Referring to FIG. 2, a detailed block diagram of one of the subscriber terminals, for example, the one indicated as 40 of the subscription television system will now be described. The broadband television signal from signal distribution system 52 is received at the input of up/down converter or tuner 100. An out-of-band data receiver 150 is also coupled to the broadband input. Conventionally, the up/down converter 100 may include an input filter, such as a diplexer, to separate the 108.2 MHz out-of-band signal and the broadband television signal. The up/down converter 100 can be tuned to a predetermined channel for receiving in-band video and audio data when not in use. The channel may be predetermined from the system manager 12 and, by one of the data transmission methods described herein, the predetermined channel identification can be stored in subscriber terminal 40.

When in use, the up/down converter 100 is tuned according to a channel entered by a subscriber via a user interface having an IR receiver 124, remote control 126 and terminal keypad 122. Up/down converter 100 uses a phase locked loop under the control of a tuning control 102 to convert the selected or predetermined default RF channel signal to a 45.75 MHz intermediate frequency signal. A multifunction control circuit (MCC) 104, preferably an application specific integrated circuit (ASIC) combining many subscriber terminal control and data handling functions into a single package, is linked to up/down converter 100 by a bidirectional link to the tuner control 102. The link has one path for timing and a return link for feedback control of the tuning process. A feedback signal for automatic gain control and one for automatic frequency control are transmitted to the up/down converter 100 through filters 101, 103, respectively from a video demodulator 109.

A filter, such as a SAW filter 106, filters the IF channel signal to split the signal into separate video and audio portions for further processing. The video portion is demodulated and descrambled by the video demodulator 109 under the control of a descrambler control 110 of the MCC 104. The video demodulator 109 performs the sync restoration (descrambling of the video signal) for sync suppression scrambling. The video signal then passes through a band pass filter 130 and to a video inverter 132 where inverse video inversion (descrambling) takes place. The descrambling of the video portion, whether sync suppression, sync inversion, video line inversion, etc. is under the control of the descrambler control 110 of the MCC 104. The descrambler control 100 provides the necessary timing signals, inversion axis levels, and whether the video is inverted or not to the video inverter 132 and supplies the necessary timing, restoration levels and identification of sync pulses to be restored to the demodulator 109. The descrambler control 110 usually receives such descrambling information from pulses as in-band audio data.

In the other path, the audio signal is converted from the 41.25 MHz IF carrier to the intermodulation frequency of 4.5 MHz by a synchronous detector 105. Feedback for automatic gain control of detector 105 is supplied from the output of band pass filter 131. The audio signal may then be demodulated by an FM demodulator 119. An amplitude modulation detector 111 performs pulse detection to recover the in-band audio data which are amplitude modulated onto the audio carrier. The recovered in-band pulses are supplied to an in-band audio data decoder 117 of MCC 104 for processing after being shaped by pulse shaper 115. The in-band data, except for descrambling data, is stored in DRAM 137 for buffering. Descrambler control 104 accesses descrambling data directly for the video descrambling operation. Volume control of the audio signal is performed under the control of a volume control 118 of the MCC 104 and the microprocessor 128 as described in U.S. Pat. No. 5,054,071, incorporated herein by reference. After volume control, the audio signal is passed through a low pass filter 123 and a mute switch 125. The output of the mute switch 125 is applied to a modulator 142.

The MCC 104 receives the video signal after demodulation and descrambling and strips the in-band video data from the VBI of the signal with a VBI decoder 129. The in-band video data is transmitted at a frequency on the order of known teletext systems, such as about 4.0 megabits per second, and a data clock provides an appropriate sampling frequency higher than the Nyquist rate according to well known techniques. The in-band decoder 129 stores the data in DRAM 137 prior to processing by the microprocessor 128, the DRAM 128 serving as a data buffer.

The output of video inversion control 1232 is also supplied to an on screen display control 127 of the MCC 104. The on screen display control 127 selectively generates on screen character and graphic displays in place of or overlaid on the video signal. The modulator 142 combines the video signal from the output of the on screen display control 127 and the audio signal from the output of the mute circuit 125 and converts the combined signal to the channel frequency selected by the microprocessor 128, such as channel 3/4 for NTSC. The combi