JPS60182891A - Two-way communications method in catv system - Google Patents

Abstract

PURPOSE:To improve time efficiency in a CATV system by setting a call from a center once to all terminals, and transmitting data signals through each terminal after a lapse of the prescribed period. CONSTITUTION:When a center 1 recovers data from each terminal device 9 in order to control pay programs and to catch the audience state, the specific calling code is transmitted to the overall terminal as down communications data. The terminal receiving the code starts simultaneously counting up its inherent allocated time. For instance, a terminal (1) transmits response data to the center after it counts a t1musec. After terminals (2) and (3) count a t2musec and a t3musec, respectively, they transmit response data. Thus losses such as a period necessary for calling each terminal and an up data transmission period can be eliminated, and data of all terminals can be recovered in an extremely short time.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a two-way communication method in a CATV system in which data is sent from a terminal in response to a transmission command from a center side.

[Prior art l] This type of two-way communication method is as shown in Fig. 1.
This has already been implemented on the ATV system A5. Here, one center 1 and a terminal device 9 are connected by a cable. ,′! In other words, a trunk cable 4 is drawn out from the center 1, and a branch 5 is provided at a predetermined location on the trunk cable 4. Multiple branch cables 6 connected to this branch B5
Tapoffs are provided at predetermined locations, and a plurality of branch cables 8 are drawn out from each tapoffer. The terminals of each branch cable 8 are drawn into each eaves 10 and connected to a terminal device 9. Na a3,
In the figure, reference numeral 11 is a control box, and 12 is a TV receiver. In the center 1, the video equipment 482 transmits television signals for each channel, while the data communication equipment 3 collects and processes data from each terminal device 9 for the purpose of managing pay programs and monitoring viewing status. The procedure is as shown in Figure 2, which forms each element of so-called serial data communication such as command data, error control data, frame synchronization, etc. corresponding to each individual terminal, and transmits each terminal equipment including downlink signals. At the same time, each terminal device 9 recognizes the corresponding call and sends data indicating the current status back to the center 1. [Technical Issues] Here, the data necessary for downlink data communication is sent back to the center 1. time is 256
Even when using a relatively high communication rate of k b ++ s and reducing the data length to 30 bits, the data length is 100 bits.
This requires a μsec radius. In addition to the above-mentioned downlink communication time, the communication system also has the same requirement for uplink time (1 in 1).
20μsea P1 degree is required, and cable 4.
(Since there is a propagation delay (approximately 80 to 90% of the speed of light) within 3 and 8, if the round trip length of the cable is 80..., the propagation delay will be more than 300 μsea, and the process time in logic will be added. The time required for two-way communication with one terminal device 9 is determined.Assuming approximately 30,000 terminal devices,
To perform two-way data communication with all terminals and cycle through 1
0 to 20 seconds are required. Furthermore, in recent years, large-scale CATV systems have been developed, and the time required for a trip tends to become longer. [Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and the call is made only once for all terminals by downlink communication from the center, and from the time when each terminal receives the call,
The present invention aims to provide a two-way communication method for a CATV system that improves time efficiency by transmitting uplink data signals after respective predetermined times.

[Structure of the Invention] For this purpose, the present invention provides a two-way communication method in which data is sent from a terminal in response to a transmission command from a center, in which the center sends a transmission command signal to all terminal devices to start transmission. , each terminal device is characterized in that it sends data to the center after waiting for a predetermined time of 4tJ built into each terminal device. [Embodiment] An embodiment of the present invention will be specifically described below with reference to FIGS. 3 and 4. The configuration of the two-way communication system is the same as that shown in FIG. 1, but as shown in FIG. Combi coater 14, video processing device 13 of T-1 terminal equipment d9,
It controls the control box 17 and the transmission of uplink communication data. The control computer 14 includes a center 1
call individually from

[Unique recognition that is one of the decisions as to whether or not to respond when tapped] - Address block 15 having a code is connected. Further, in this address block 15, when all 9η; of 11& are called or GJ is called, the time of each setting until sending out response communication data is also stored. <k, figure center mark @
16t and 1 are power supply devices, and 18 is a television receiver cable. In such a configuration, as described above, the center 1 manages each terminal device 9 for the purpose of managing pay programs and understanding the viewing status.
When collecting data from the network, first, a specific call code for the entire network is transmitted as downstream communication data. A terminal that receives this code will receive address block 1 at the same time as receiving it.
Start counting the unique time stored in 5. For example, as shown in diagram M3, terminal (1) sends response data to the center after t1 μsec, and then terminal (2) sends response data to the center. (3) transmits response data to the center after counting t2μsec, t, and μSeC, respectively. In this way, one piece of uplink data is processed at the center side, and immediately after it is stored, the next upstream data enters the center side. This means that one round of data collection can be performed from all terminals in an extremely short amount of time. In the above explanation, data communication is established based on a call from the center side, but it is also possible to establish data communication based on a call from the terminal side. Only in this case, the terminal that experienced the change sends an extremely short uplink signal to the center that is unlikely to overlap with the same signal from other terminals, and the center that receives this specific signal prohibits the transmission of this specific signal to all terminals. After sending the data, it collects the data in the same manner as described above, and after that, it sends the data for permission to send a specific signal.Also, since it has a built-in individual address block, it can perform the same communication as before. It is also possible to re-communicate with a terminal that has failed to communicate after completing a cycle. [+f@aki effect] As detailed above, the present invention is capable of collecting data from a large number of terminals. This is done in one call, which reduces the time spent on downlink communication, and also eliminates the loss of uplink transmission time, greatly reducing the time it takes to make one round to all terminals.In other words, For example, a single 0ATV system can be used to exchange ceiling-mounted data, making it possible to keep up with scale expansion.

[Brief explanation of drawings]

Fig. 1 is a system diagram conceptually showing the communication form of a general CATV system, Fig. 2 is a timetable showing a conventional bidirectional communication method, and Fig. 3 is a bidirectional communication method showing one form of the present invention method. FIG. 4 is a configuration diagram of a terminal for implementing the above embodiment. 1...Center, 2...Video equipment, 3...Data communication equipment, 4...Main line-pull, 5...Switchout, 6
... Branch cable, 1 ... Tap-off, 8 ... Branch cable, 9 ... Terminal device, 10 ... Home, 11
... Control box, 12... Television receiver, 13... Video processing device, 14... Control computer, 15 Address block, 16... Power supply device, 1
7...:l control box, 18...TV receiver cable. Patent applicant: Pioneer Co., Ltd. Agent: Nobuko Kobashi, patent attorney: Susumu Murai, patent attorney

Claims (1)

[Claims] In a two-way communication method in which data is sent from a terminal after receiving a transmission command from the center, the center sends a transmission command signal to all terminal devices to start transmission, and each terminal device
A two-way communication method in an ATV system characterized by transmitting data to a center after each individual waits for a predetermined time.