JPH0738666B2 - Subscriber optical transmission method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bidirectional subscriber optical transmission method of supplying power to an optical transmission device to establish a transmission link each time a call occurs.

"Prior art" In the subscriber optical transmission system using an optical fiber for the transmission line, the optical transmission equipment installed in the subscriber's house is supplied with power from the commercial power source at the subscriber's expense, so the power consumption is reduced. It is extremely important to measure Therefore, for example, when there is no call, power is supplied to only a small part of the transmission device, that is, the call detection unit and the optical reception unit, and the power is supplied to the entire transmission device to establish a transmission link each time a call occurs. A so-called Call by Call power supply method has been proposed (for example, Japanese Patent Application No. 59-29204: optical fiber transmission method).

By the way, in the subscriber optical transmission system, since the transmission band of the optical fiber as a transmission medium is wide, it is possible to perform various transmissions by multiplexing from broadband information such as video transmission service to narrow band information such as telephone service. It is possible to receive services at the same time. Among services that can be provided by the subscriber optical transmission system, for example, telephone service requires backup of the transmission device by using a battery so that the service can be received even in case of power failure. This battery is usually charged from a commercial power source and supplies power to the transmission device during a power failure. It goes without saying that it is important to reduce the power consumption during a call during a power failure as much as possible in order to reduce the volume and weight of this battery. On the other hand, for example, in video transmission services, there is little need for backup at the time of power failure. Now, assuming that both wideband information such as video transmission services and narrowband information such as telephone services are all digital, in a system that multiplexes all of this information and transmits at a constant bit rate, high-speed digital signals are always transmitted during service. Because of the necessity of transmitting and receiving, the power consumption during a call will inevitably increase regardless of whether or not there is a power outage.

"Means for Solving Problems" In order to solve this problem, the present invention transmits / receives a high-speed digital optical signal when an optical transmission device installed in a subscriber's home receives power from a commercial power source. If the backup battery is used, the capacity of the backup battery is reduced by transmitting / receiving a low-speed digital optical signal.

[Embodiment] Subscriber side apparatus FIG. 1 shows an optical transmission apparatus used on the subscriber side in an embodiment of the present invention. The power supply unit 1 of this optical transmission device is
Normally, the power is supplied from the commercial power supply, and when the power cannot be supplied from the commercial power supply, such as during a power failure, the built-in backup battery is used to supply the power necessary for the operation of each unit.
This optical transmission device is connected to a non-telephone terminal via a terminal interface connector 2 and to a telephone terminal via a terminal interface connector 3 by a metal cable shown on the left side of the drawing. Here, it is assumed that the non-telephone terminal is used for a service for transmitting broadband information such as video. A plurality of communication lines are housed in the metal cable. The terminal interface connector 2 is connected to the interface section 4 and the call detection section 5, and the terminal interface connector 3 is connected to the interface section 6 and the call detection section 7, respectively. The interface units 4 and 6 send and receive signals to and from the terminals. Calling of the terminal is performed, for example, by forming a DC loop on a specific communication line in the metal cable, and the call detecting units 5 and 7 detect the call by, for example, a change in DC resistance.

Here, it is assumed that the signal passed from the interface section 4 to the multiplexing section 8 or from the demultiplexing section 9 to the interface section 4 is a high-speed digital signal. It is also assumed that the signal passed from the interface section 6 to the multiplexing section 10 or from the demultiplexing section 11 to the interface section 6 is a low-speed digital signal. Note that the signals transmitted and received between the interface units 4 and 6 and the terminal may be analog or digital, but in the case of analog, the interface units 4 and 6 need the function of A / D conversion and D / A conversion. Is.

The multiplexing unit 10 multiplexes the low-speed digital signal delivered from the interface unit 6 and the supervisory control signal delivered from the supervisory control unit 12, and sends the multiplexed signal to the multiplexer 8 and the switch 13. It should be noted that the supervisory control signal is generally much slower than the slow digital signal. The multiplexing unit 8 multiplexes the high-speed digital signal transferred from the interface unit 4 and the low-speed digital signal transferred from the multiplexing unit 10 and sends it to the switch 13. The switch 13 receives the signal passed from the multiplexing unit 8 when the optical transmission device is operated by receiving power from a commercial power source, and receives the signal from the multiplexing unit 10 when operating with the backup battery. The passed signal is selected and sent to the electro-optical conversion unit 14. The electro-optical conversion unit 14 converts the digital signal transferred from the switch 13 into an optical signal, and sends this to the optical transmission device on the center side via the optical connector 15.

The optical transmission device on the subscriber side is connected to the optical transmission device on the center side by an optical fiber cable through optical connectors 15 and 16. On the contrary, the opto-electric converter 17 receives the digital optical signal sent from the optical transmission device on the center side via the optical connector 16, converts it into an electric signal, and extracts the timing extraction circuits 18 and 19 and the identification reproduction circuit 20. , 21 respectively. If the wavelength division multiplexing technique is applied as is well known, it is possible to perform bidirectional transmission with the center side using only one fiber by using the optical multiplexer / demultiplexer. The timing extraction circuit 18 extracts a high-speed timing component from the received signal to reproduce the clock signal. The discriminating / reproducing circuit 20 discriminates and reproduces the high-speed data sequence of "1" and "0" from the received signal by using the high-speed clock signal, and sends it to the separating unit 9. The timing extraction circuit 19 extracts the low-speed timing component to reproduce the low-speed clock signal, and the identification / reproduction circuit 21 identifies / reproduces the low-speed data string received using the low-speed clock signal.

When this optical transmission device operates by receiving power from a commercial power source, the timing extraction circuit 18 and the identification reproduction circuit 20 that operate at high speed operate, and when operating on the backup battery, the timing extraction circuit 19 operates at low speed. The identification reproduction circuit 21 operates. The separation unit 9 separates the signal received from the identification / reproduction circuit 20 into a high-speed digital signal to be passed to the interface unit 4 and a low-speed digital signal to be passed to the switch 22, and each of them is passed. The former is wideband information to be passed to the non-telephone terminal, and the latter is narrowband information to be passed to the telephone terminal and the supervisory control information to be passed to the supervisory control unit 12 are multiplexed. The switch 22 receives the signal passed from the separation unit 9 when the optical transmission device is operated by being supplied with power from the commercial power source, and the identification reproduction circuit 21 when operated by being supplied with power from the backup battery. The passed signal is selected and passed to the separating unit 11. The separation unit 11 separates the signal passed from the switch 22 into a low-speed digital signal passed to the interface unit 6 and a supervisory control signal passed to the supervisory control unit 12, and delivers them to each.

The monitoring control unit 12 monitors the operating state of each unit of the optical transmission device, sends monitoring information to the optical transmission device on the center side, and controls the power supply to the power supply unit 1 and the interface units 4 and 6 using, for example, a metal cable. A control is performed to form a DC loop on a particular communication line in the terminal to activate the terminal to initiate an incoming call.

When this optical transmission device is supplied with power from a commercial power supply, power is constantly supplied to the call detection units 5 and 7, the photoelectric conversion unit 17 and the timing extraction circuit 18, and a call is generated to any of the terminals. Then, in addition to the above, those involved in the generated call among the interface units 4 and 6 and the multiplexing units 8 and 10, the demultiplexing units 9 and 11, the supervisory control unit 12, the electro-optical conversion unit 14 and the identification reproduction circuit 20 are also included. Power is supplied. Such power supply is called by Call
by Call) called power supply. Of course, it is possible that calls will be made to both non-telephone terminals and telephone terminals at the same time.
In that case, power is supplied to both the interface units 4 and 6. For the purpose of shortening the start-up time and stabilizing the operation, it is conceivable that each of the units to which call-by-call power supply is applied, such as the monitor control unit 12, is always supplied with power.

When this optical transmission device operates on the backup battery, power is constantly supplied to the call detection unit 7, the photoelectric conversion unit 17, and the timing extraction circuit 19, and when a call is generated at the telephone terminal, the interface unit 6 is also provided. Power is also supplied to the multiplexing unit 10, the demultiplexing unit 11, the monitoring control unit 12, the electro-optical conversion unit 14, and the identification reproduction circuit 21. Here, comparing the multiplexers 8 and 10, the demultiplexers 9 and 11, the timing extraction circuits 18 and 19, and the identification and reproduction circuits 20 and 21, the former operates at high speed, while the latter operates at low speed. Since it is an operation, the latter consumes much less power than the former. Therefore, when this optical transmission device operates with a backup battery, especially during a call,
The power consumption is much lower than when operating from a commercial power supply.

Center Side Device FIG. 2 shows an example of an optical transmission device used on the center side in the embodiment of the present invention. This optical transmission device uses an optical connector on the subscriber side and an optical fiber cable to connect an optical connector.
Connected via 23,24. These optical connectors 23 and 24 are respectively connected to the electro-optical converting section 25 and the opto-electric converting section 26. The electro-optical conversion unit 25 converts a digital electric signal into an optical signal and sends it to the optical transmission device on the subscriber side via the optical connector 23, and the opto-electric conversion unit 26 reversely transmits the optical signal on the subscriber side. The digital optical signal sent from the device is received through the optical connector 24, converted into an electric signal, and supplied to the timing extraction circuits 27, 29 and the identification reproduction circuits 28, 30.

The timing extraction circuit 27 extracts a high-speed timing component from the received signal and reproduces the high-speed clock signal, and the identification reproduction circuit 28 identifies and reproduces the high-speed data string by the high-speed clock signal. The timing extraction circuit 29 extracts a low-speed timing component from the received signal to reproduce the low-speed clock signal, and the identification reproduction circuit 30 uses the low-speed clock signal to identify and reproduce the low-speed data string. In the separation unit 31, the high-speed data string received from the identification reproduction circuit 28 is transferred to the interface unit 32, and the high-speed digital signal and the switch 33 are transferred.
It is separated into low-speed digital signals to be passed to and passed to each. The former is wideband information required for communication of non-telephone terminals, and the latter is narrowband information required for communication of telephone terminals and the supervisory control information to be passed to the supervisory control unit 34. Under the control of the monitor control unit 34, the switch 33 selects either the signal received from the separation unit 31 or the signal received from the identification reproduction circuit 30 and sends it to the separation unit 35. The separation unit 35 separates the signal received from the switch 33 into a low-speed digital signal to be passed to the interface unit 36 and a supervisory control signal to be passed to the supervisory control unit 34, and delivers them to each.

The optical transmission device on the center side is connected to another device on the center side, for example, a switch or the like via a metal cable through interface connectors 37 and 38. The interface unit 32 performs transmission / reception of high-speed digital signals required for communication of non-telephone terminals with other devices on the center side via the interface connector 37, and the interface unit 36 transmits the high-speed digital signals to the telephone terminal via the interface connector 38. It transmits and receives low-speed digital signals required for communication with other devices on the center side. The multiplexing unit 39 multiplexes the low-speed digital signal passed from the interface unit 36 and the supervisory control signal passed from the supervisory control unit 34, and sends the multiplexed signal to the multiplexer 40 and the switch 41. Multiplexer 40
Then, the high-speed digital signal passed from the interface unit 32 and the low-speed digital signal passed from the multiplexing unit 39 are multiplexed and sent to the switch 41. Under the control of the monitoring controller 34, the switch 41 selects either the signal received from the multiplexer 39 or the signal received from the multiplexer 40 and sends it to the electro-optical converter 25.

The monitoring control unit 34 monitors the operating state of each unit of the center side optical transmission device, and sends the monitoring information to the optical transmission device on the subscriber side. Also, by monitoring the level of the timing component extracted by the timing extraction circuits 27, 29, the optical transmission device on the subscriber side sends out a high-speed digital signal, a low-speed digital signal, or both of them. The switch 33,4 based on the result.
Performs switching control for 1. Further, the power supply to the power supply unit 42 is controlled. In the center side optical transmission device, the electro-optical conversion unit 25 is supplied with call-by-call power, and the other parts are always supplied with power.

Operation during commercial power supply Next, the procedure for establishing a transmission link between the optical transmission device on the center side and the optical transmission device on the subscriber side each time a call occurs will be described. First, the procedure when the optical transmission device on the subscriber side operates by receiving power from a commercial power source will be described. When a call is made from a non-telephone terminal or a telephone terminal, the call detection unit 5 or 7 detects the call and controls power supply to the power supply unit 1, and the electro-optical conversion unit 14 sends out a high-speed digital optical signal. Then, in the optical transmission device on the center side, the output level of the timing extraction circuit 27 becomes a certain value or more, and the monitor control unit 34 detects this and thereby knows that the terminal has made a call.

Next, the supervisory control unit 34 controls the switches 33 and 41 to pass the high-speed digital signal, and also controls the power supply to the power supply unit 42. Then, the electro-optical conversion unit 25 sends a high-speed digital optical signal to the optical transmission device on the subscriber side. A frame is formed in this signal. When the optical transmission device on the subscriber side receives this optical signal and establishes the frame synchronization in the demultiplexing unit 9, the optical transmission device on the subscriber side constructs a frame for the high-speed digital optical signal to be sent to the optical transmission device on the center side. The optical transmission device on the center side is notified that the transmission link of the optical transmission line heading for is established. If frame synchronization is established in the demultiplexing unit 31 of the optical transmission device on the center side, it means that the transmission link between both optical transmission devices has been established. The optical transmission equipment on the subscriber side also establishes a transmission link between the interface unit 4 or 6 and the calling terminal. Then, communication is started between the calling terminal and another device on the center side.

On the other hand, when an incoming call activation occurs from any other device on the center side to any of the terminals, a activation signal is sent to the monitoring control unit 34 via the interface unit 32 or 36, and the monitoring control unit 34
When detecting this, the power supply control is performed on the power supply unit 42, and the switch 34 controls the switch 41 to send a high-speed digital signal to the optical transmission device of the subscriber. When the optical signal is received by the optical transmission device on the subscriber side, the timing extraction circuit 18
The output level of is above a certain value, and the monitoring control unit 12 detects this to know the incoming call. Then, power supply control to the power supply unit 1 is performed, and a high-speed digital optical signal is transmitted from the electro-optical conversion circuit 14. When the frame synchronization is established in the demultiplexing unit 9, a frame is constructed for this high-speed digital optical signal, and the establishment of the transmission link of the optical transmission line from the center side to the subscriber side is notified to the optical transmission device on the center side. Be notified. If frame synchronization is established in the demultiplexing unit 31 of the optical transmission device on the center side, it means that the transmission link between both optical transmission devices has been established. The optical transmission device on the subscriber side also forms a DC loop on the specific communication line at the interface unit 4 or 6 to notify the corresponding terminal of the incoming call and establish a transmission link between them. Then, communication is started between the other device on the center side and the corresponding terminal.

If a call is made to one terminal while another terminal is making a call and the call is made to the other terminal, the transmission link between both optical transmission devices is maintained and the optical connection between that terminal and the subscriber side is maintained. A transmission link with the transmission device is established and communication is started.

When the communication is terminated, the DC loop formed by the terminal is released in the case of a call, and the activation signal transmitted from another device on the center side is stopped in the case of a call. In the latter case, the optical transmission device on the center side notifies the optical transmission device on the subscriber side that the activation signal has been stopped, whereby the formation of the DC loop in the interface unit 4 or 6 is released. In either case, when the DC loop is released,
Immediately, the transmission link established between the terminal and the optical transmission device on the subscriber side is released. The optical transmission device on the subscriber side constantly notifies the optical transmission device on the center side whether or not each terminal forms a DC loop, and the supervisory control unit 34 of the optical transmission device on the center side monitors both terminals. When it is known that the communication has been completed, the optical signal transmission to the optical transmission device on the subscriber side is stopped. Next, the optical transmission device on the subscriber side stops the optical signal transmission to the center side when it detects the optical signal input interruption due to the output level of the timing extraction circuit 18 becoming a certain value or less, and the original non-call state. Return to.

Operation when Powered by Battery Next, the procedure when the optical transmission device on the subscriber side is operated by the backup battery will be described. When there is a call from the telephone terminal, the call detection unit 7 detects this and controls the power supply to the power supply unit 1, and the electro-optical conversion unit 14 sends out a low-speed digital optical signal. Then, in the optical transmission device on the center side, the output level of the timing extraction circuit 27 remains below a certain value, but the output level of the timing extraction circuit 29 exceeds a certain value, and the monitoring control unit 34 detects this. Know that the telephone terminal has made a call, and that the optical transmission device on the subscriber side is operating on the backup battery.

Next, the supervisory control unit 34 controls the switches 33 and 41 to pass the low speed digital signal, and also controls the power supply to the power supply unit 42. Then, the electro-optical conversion unit 25 sends out the low-speed digital optical signal, and the transmission link of the optical transmission line is established in both directions. At the same time, a transmission link between the telephone terminal and the interface unit 6 is established, and communication is started between the telephone terminal and another device on the center side. Since the call detection unit 5 does not operate even when a call is made from the non-telephone terminal,
The call is eventually ignored.

In addition, when an incoming call is activated from another device on the center side to the telephone terminal, the optical transmission device on the center side first sends out a high-speed digital optical signal, but the optical transmission device on the subscriber side does not respond. For example, in several tens to several hundreds of milliseconds, the switches 33 and 41 are switched to the low speed digital signal side and the low speed digital optical signal is transmitted. Then, the optical transmission device on the subscriber side detects an incoming call when the output level of the timing extraction circuit 19 becomes a certain value or more, and the transmission link of the optical transmission line and the transmission link with the telephone terminal are established. Communication is started. It should be noted that even if the incoming call from the other device on the center side to the non-telephone terminal is activated, the transmission link between the subscriber's optical transmission device and the non-telephone terminal is not established. It will be. The procedure for ending the communication of the telephone terminal is the same as that for the case where the optical transmission device on the subscriber side is supplied with power from the commercial power source.

In the embodiment described above, for the purpose of shortening the start-up time at the time of making and receiving a call, the electro-optical conversion unit 25 is always supplied with power, and a pattern (for example, all "1") that does not include a timing component during no call is used. The digital optical signal may be always transmitted. When multiple non-telephone terminals or telephone terminals are connected to the optical transmission equipment on the subscriber side, a transmission link is established when a call occurs at any one of the terminals, and all terminals terminate communication. It is easy to extend the above embodiment to return to the non-call state.

[Advantages of the Invention] As described above, according to the present invention, when the optical transmission device on the subscriber side is operated by the backup battery at the time of power failure, etc., only low-speed digital signals are transmitted and received. The power consumption during a call can be significantly reduced, and thus the effect of reducing the capacity of the backup battery is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing an optical transmission device on the subscriber side in an embodiment of the present invention, and FIG. 2 is a block diagram showing an optical transmission device on the center side in an embodiment of the present invention. 1 ... power supply part, 2, 3 ... terminal interface connector,
4 ... interface unit, 5 ... call detection unit, 6 ... interface unit, 7 ... call detection unit, 8 ... multiplexing unit,
9 ... Separation unit, 10 ... Multiplexing unit, 11 ... Separation unit, 12 ...
Monitoring and control unit, 13 ... Switch, 14 ... Electro-optical conversion unit, 1
5,16 …… Optical connector, 17 …… Optical-electrical converter, 18,19 ……
Timing extraction circuit, 20, 21 …… Identification reproduction circuit, 22 ……
Switch, 23,24 ... Optical connector, 25 ... Electro-optical converter, 26 ... Optical-electric converter, 27 ... Timing extraction circuit,
28 ... Identification and reproduction circuit, 29 ... Timing extraction circuit, 30 ...
... Identification and reproduction circuit, 31 ... Separation unit, 32 ... Interface unit, 33 ... Switch, 34 ... Monitoring control unit, 35 ... Separation unit, 36 ... Interface unit, 37,38 ... Interface Connector, 39, 40 …… Multiplexing unit, 41 …… Switch, 42
……Power supply part.

Claims (1)

[Claims] 1. An optical transmission device on the subscriber side and an optical transmission device on the center side are connected by an optical transmission line, and the optical transmission device on the subscriber side is an optical line from the optical transmission line when there is no call. A photoelectric conversion unit that receives a signal, a high-speed timing extraction circuit connected to the output side of the photoelectric conversion unit, a non-telephone call detection unit connected to a non-telephone terminal,
Power is supplied only to the telephone call detection unit connected to the telephone terminal, and when a call is detected by the non-phone call detection unit or the telephone call detection unit in a non-call state, the non-phone call is detected. A multiplexing unit that multiplexes a high-speed digital signal from a terminal and a low-speed digital signal from the telephone terminal, and an electro-optical conversion unit that converts the multiplexed output into an optical signal and outputs the optical signal to the optical transmission line. A high-speed identification / reproduction circuit for identifying and reproducing the output of the opto-electric conversion unit, and separating the output of the high-speed identification / reproduction circuit into a high-speed digital signal and a low-speed digital signal and sending them to the non-telephone terminal and the telephone terminal. When the digital light signal is sent to the optical transmission device on the center side by supplying power also to the separation unit, and the optical transmission device on the center side extracts the timing component from the digital optical signal received from the optical transmission line, Above subscription A digital optical signal is sent to the optical transmission device on the operator side, frame synchronization is established in bidirectional optical transmission between the optical transmission devices, and communication is performed between the terminal and other devices on the center side. When an incoming call is activated from another device on the center side to a terminal in a no-call state, the optical transmission device on the center side sends a digital optical signal to the optical transmission device on the subscriber side, The optical transmission device on the side of the operator detects this by the output of the timing extraction circuit, supplies power to each part to be supplied when a call is detected, and sends a digital optical signal to the optical transmission device on the side of the center. When bidirectional frame synchronization is established between the optical transmission devices and communication is performed between the other device on the center side and the terminal, and when the communication is completed, the optical transmission device on the center side sends out a digital optical signal. Stop Or change its signal pattern, the optical transmission apparatus of the subscriber side when detecting whether input interruption or the change signal pattern of the digital optical signal,
A method for returning to the original non-communication state, wherein the optical transmission device on the subscriber side selects one of the output of the multiplexer and the low-speed digital signal and supplies it to the electro-optical converter. A switch, a low-speed timing extraction circuit that extracts the timing component of the low-speed digital signal from the output of the opto-electric conversion unit, and a low-speed identification and reproduction circuit that identifies and reproduces the low-speed digital signal from the output of the opto-electric conversion unit, A second switch for selecting one of the low-speed digital signal from the separating section and the low-speed digital signal from the low-speed discriminating and reproducing circuit and transmitting it to the telephone terminal is provided, and the optical transmission device on the subscriber side is a commercial power source. When the power is supplied from the first switch, the first switch selects the output of the multiplexer, and the second switch outputs the low-speed digital signal from the separator during a call. If a high-speed digital optical signal is transmitted / received to / from the optical transmission device on the center side and the optical transmission device on the subscriber side is supplied with power from a backup battery, the first signal is transmitted during a call. The switch selects the low-speed digital signal, and the second switch selects the output of the low-speed discriminating / reproducing circuit to transmit / receive the low-speed digital optical signal to / from the optical transmission device on the center side. Subscriber optical transmission method.