JP2968684B2 - Digital trunk system selection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital trunk system for terminating a PCM digital line in a digital electronic exchange.

[0002]

2. Description of the Related Art In a digital electronic exchange having a single digital trunk for terminating a conventional PCM digital line and a dual line controller for controlling a PCM digital line through the digital trunk, the single digital trunk is duplicated. The working system clock signal and the working data signal are selected from the working line control devices, and when the working system clock signal is disconnected for some reason, the working line control device detects a failure and sends it to the central processing unit. When the central processing unit switches the active line controller, the digital trunk selects a clock signal and a line data signal from the line controller.

Therefore, it takes a lot of time to switch the system selection in the digital trunk, and during that time, the channels accommodated in the digital trunk are in a non-signal state.

An example of a digital electronic exchange having a single digital trunk for terminating the PCM digital line and a dual line controller for controlling the PCM digital line through the digital trunk is disclosed in, for example, Japanese Unexamined Patent Publication No. There is one described in "Digital Trunk Test System" in JP-A-63-217759.

Referring to FIG. 1, a digital electronic exchange comprises a central processing unit 1 and a time division switch 2 for performing a time division switching operation of a digital multiplexed signal on a highway under the control of the central processing unit 1. A digital multiplexing device 4 for multiplexing and demultiplexing a plurality of digital lines, and a central processing unit provided on a highway between the digital multiplexing device 4 and the time division switch 2 through the time division switch 2. A dropper inserter 3 for extracting and inserting line control information with the device 1; a digital trunk 6 provided between the digital line and the digital multiplexer 4; and a digital trunk connected to the dropper inserter 3 And a line control device 5 for controlling the digital trunk 6. The above devices other than the digital trunk 6 are duplicated. To have. Digital trunk 6
Has a switching circuit 61 at the connection to the digital line, disconnects the incoming and outgoing sides of the digital line under the control of the line controller 5, and connects the incoming and outgoing sides inside the digital trunk. And a loop can be formed.

[0006]

In the conventional digital trunk test system, when a failure occurs in a line controller of an active system or a communication failure between the active system and the digital trunk, the system selection in the digital trunk is performed. It takes several seconds to switch, during which time the channel using this digital trunk has a problem of no signal.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a digital trunk which selectively receives a clock signal and a line data signal from an active system in a duplicated line controller and constantly monitors the clock signal. The system selection method of the digital trunk system that significantly reduces the no-signal state until the system selection is switched by selecting the clock signal and the line data signal from the standby system among the redundant line controllers when the system is disconnected. To provide.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a digital
In a digital electronic exchange comprising a single digital trunk for terminating a PCM digital line and a duplicated line control device for controlling the PCM digital line through the digital trunk, the digital trunk comprises: Duplicated number
Clock signals from the first and second line controllers are respectively
A first and a second clock monitoring circuit for constantly monitoring;
1, by the respective control signals from the second line controller.
A system determination circuit for determining which is the active system;
One of the clocks from the second clock monitoring circuit
When the system determination circuit detects the disconnection of the lock signal, the system determination is performed.
The first and second rounds based on the selection signal from the constant circuit.
System selection circuit that selects the specified one of the line controllers
And a line termination circuit for terminating the PCM digital line
It is provided with.

Further, the digital trunk first been pre Symbol duplicated, first to each constantly monitors the clock signal from the second line controller, and the second clock monitoring circuit, the clock monitoring circuit wherein A system determination circuit for determining which of the control signals from the first and second line control devices is the active system when detecting the interruption of the clock signal; and the first system control circuit based on a selection signal from the system determination circuit. , Second
And a line terminating circuit for terminating the PCM digital line.

[0010]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a digital trunk system selection system according to the present invention.

Referring to FIG. 1, a digital electronic exchange according to the present embodiment includes a single digital trunk 1 for terminating a PCM digital line 6 and a digital trunk 1 for the digital trunk.
And a dual line controller 2A and 2B for controlling the PCM digital line 6 through the network. The digital trunk 1 receives clock signals 3A and 3B, control signals 4A and 4B, and line data signals from the line controllers 2A and 2B, respectively. 5A and 5B.

The digital trunk 1 has a clock signal 3
Clock monitoring circuits 13A and 13 for constantly monitoring A and 3B
B, a system determination circuit 12 for determining which of the control signals 4A, 4B is the active system when the clock monitoring circuits 13A, 13B detect the interruption of the clock signals 3A, 3B, and a selection signal 15 from the system determination circuit 12. Line controller 2 based on
A system selection circuit 11 for selecting a designated one of A and 2B
And a line termination circuit 1 for terminating the PCM digital line 6.
4 is provided.

Next, the operation of this embodiment will be described.

The system determining circuit 12 receives the control signal 4A from the line controller 2A and the control signal 4B from the line controller 2B, determines the active system, and sends a selection signal 15 to the system selecting circuit 11.

In the system selection circuit 11, based on the selection signal 15, the clock signals 3A and 3B and the control signals 4A and
4B and one of the line data signals 5A and 5B, and transmits the selected signal to the line termination circuit 14.

Here, the clock signals 3A and 3B, the control signals 4A and 4B, and the line data signals 5A and 5B have the same contents , but the control signals 4A and 4B have the same contents.
In the above, the system control circuit 2A
To determine which is the active system
For this purpose, the control signals 4A and 4B indicate whether the system is active or standby.
Contains data that can be determined.

The clock monitor circuit 13A, 13B is click lock <br/> click signal 3A, each of which is constantly monitored 3B, and notifies the system determination circuit 12 when determining the interruption of the clock signal.

[0019] In the system determination circuit 12, if the silicic determined that disconnection of the clock signal is active system, and sends the selection signal 15 to the system selection circuit 11 to select the auxiliary system, the system selection circuit 1
1 switch the system selection.

[0020] That is, if the line control device 2A and the working system, the clock monitor circuit 13A when determines the interruption of the clock signal 3A system determining circuit 12 is system selection circuit 11 to select the signal 15 sent by the line control apparatus 2B To select.

[0021]

As described above, the present invention provides a PCM
A single digital trunk that terminates a digital line
PCM digital line through this digital trunk
And a dual line controller for controlling the
Digital trunks are duplicated in the electronic exchange
Clock signal from the working system in the
Selective reception of line data signal and clock from active system
Clock monitoring means for constantly monitoring signals, and
Redundant line control device when clock signal is cut off
Clock signal from the standby system and line data signal
System selection means for selecting
In one embodiment, the digital trunk is
Clock signals from the first and second line control devices
First and second clock monitoring circuits for constantly monitoring each
And that the clock monitoring circuit has detected the loss of the clock signal.
Which of the control signals from the first and second line control devices
A system decision circuit for determining whether the system is the active system, and a selection from the system decision circuit
Of the first and second line controllers based on the selection signal.
System selection circuit to select the specified one, and PCM digital
By obtaining Bei a line termination circuit for terminating a line, significantly the duration of the no-signal state of the channel using a digital trunk when communication failure between the disaster or working with digital trunk of the working system This has the effect that it can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a digital trunk system selection system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Digital trunk 2A, 2B Line controller 3A, 3B Clock signal 4A, 4B Control signal 5A, 5B Line data signal 6 PCM digital line 11 System selection circuit 12 System determination circuit 13A, 13B Clock monitoring circuit 14 Line termination circuit 15 Selection signal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-288032 (JP, A) JP-A-4-54052 (JP, A) JP-A-58-72226 (JP, A) JP-A-63-1988 217759 (JP, A) JP-A-2-187833 (JP, A) JP-A-4-15835 (JP, A) JP-A-63-299646 (JP, A) JP-A-57-204669 (JP, A) JP-A-4-156156 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04Q 3/42-3/42 107 H04M 3/22-3/36

Claims (1)

(57) [Claims] 1. A digital electronic exchange comprising a single digital trunk for terminating a PCM digital line and a dual line controller for controlling the PCM digital line through the digital trunk, wherein the digital trunk is provided with the duplicated trunk. First, first
Clock signals from the two line controllers are constantly monitored
The first and second clock monitoring circuits,
2 depending on the control signal from each line controller
A system determining circuit for determining whether the system is an active system;
From one of the clock monitoring circuits
When the system determination circuit detects disconnection of the signal, the system determination circuit
The first and second line control devices based on these selection signals.
A system selection circuit for selecting a designated one of the
A digital trunk system selection method, comprising: a line termination circuit for terminating a CM digital line .