JPH06125331A - Digital line terminator - Google Patents

Abstract

PURPOSE:To obtain a digital line terminator easily detecting the occurrence of a fault in an equipment. CONSTITUTION:A horizontal/vertical parity generating section 23 provided to a sender side of a function element generates a horizontal and vertical parity in data transmission between the function elements implementing digital signal processing with parallel data from the digital line terminator 100 and a horizontal/vertical parity collation section 24 provided to a receiver side collates the horizontal/vertical parity to detect a fault caused in the equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital line terminating device for relaying an optical signal, and more particularly to a digital line terminating device having a device fault detecting function.

[0002]

2. Description of the Related Art The configuration of a conventional digital line terminating device of this type will be described with reference to the block diagram of FIG.

The digital line termination device 101 shown in FIG.
The downlink optical signal in digital form received from the optical transmission line to the optical input terminal 25 is converted into an electric signal and subjected to digital signal processing, and then converted into an optical signal again and output from the optical output terminal 34. The line terminating device 101 is an optical / electrical conversion unit (O / O) that converts an optical signal from the optical input terminal 25 into an electric signal of serial data, as a functional component in the downstream transmission direction.
E) 26, a serial / parallel conversion unit (S / P) 27 for converting the serial data into parallel data (data width W bits), and an SOH termination unit 28 for terminating the section overhead (SOH) of the parallel data. ,
A POH termination unit 29 that terminates the path overhead (POH) of the parallel data, a POH insertion unit 30 that generates POH and inserts it into the parallel data, and a SOH insertion unit 31 that generates SOH and inserts it into the parallel data.
And a parallel / serial converter (P / S) 32 for converting the parallel data after inserting the POH and SOH into serial data, and an electric signal of the serial data is converted into an optical signal and supplied to the optical output terminal 34. And an electric / optical conversion unit (E / O) 33.

Further, the digital line terminal 101 is
The upstream optical signal received from the optical transmission line to the optical input terminal 35 is converted into an electric signal and processed, and then converted into an optical signal again and output from the optical output terminal 44. The line terminating device 101 uses the optical input terminal 35 as a functional component in the downlink transmission direction.
Optical / electrical converter 36 for converting the optical signal from the optical data into an electric signal of serial data, a serial / parallel converter 37 for converting the serial data into parallel data (data width W bits), and a section overhead of the parallel data. SOH terminating unit 38 terminating (SOH), POH terminating unit 39 terminating the path overhead (POH) of the parallel data, POH inserting unit 40 for generating POH and inserting it in the parallel data, and SOH generating SOH insertion unit 41 for inserting the parallel data into the parallel data
And a parallel / serial conversion unit 4 for converting parallel data after inserting the POH and SOH into serial data.
2 and an electric / optical conversion unit 43 which converts the electric signal of the serial data into an optical signal and supplies the optical signal to the optical output terminal 44.

[0005]

In the above-mentioned digital line terminating device, data transmission between the functional components for processing an electric signal into a digital signal is performed by parallel data, and a data error occurs due to the transmission error of the parallel data. Even if it occurred, this error could not be detected, and as a result, the failure that occurred in the device could not be detected.

[0006]

A digital line terminating device of the present invention comprises an optical / electrical conversion unit for converting a first optical signal into a serial-type first electric signal, and a parallel first electric signal. A digital signal processing section for converting the data into at least one digital signal processing and converting the parallel data after the digital signal processing into a second electric signal in a serial format; and a second electric signal for the second electric signal.
In the digital line terminating device including an electric / optical conversion unit for converting the optical signal into the optical signal, the digital signal processing unit is provided for each functional unit of the digital signal processing on the output side of the functional unit to perform horizontal and vertical parity. A parity generation unit for generating and a parity collation unit provided on the input side of the functional unit for collating the horizontal and vertical parities are provided.

An embodiment of the digital line terminating device of the present invention is an optical / electrical conversion unit for converting a first optical signal input from an external circuit into a serial-type first electric signal, and the first optical signal conversion unit. Serial / parallel conversion unit for converting the electric signal of the above into parallel data, a SOH termination unit for terminating the section overhead of the parallel data, and the above S
A POH termination unit that terminates the path overhead of the parallel data from the OH termination unit, a POH insertion unit that generates a path overhead and inserts it into the parallel data from the POH termination unit, and a POH insertion unit that generates SOH. SOH inserting section for inserting parallel data from the
The parallel data from the OH insertion part is converted into the second serial data.
A parallel / serial conversion unit for converting the second electric signal into a second optical signal and outputting the second optical signal to an external circuit. The serial / parallel conversion unit , The SOH terminating unit, the POH terminating unit, the POH inserting unit and the SOH inserting unit each further include a parity generation unit for inserting horizontal and vertical parity into the parallel data to be output, and the SOH terminating unit, The POH terminal portion, the POH insertion portion, the SOH
Each of the insertion unit and the parallel / serial conversion unit,
A parity collating unit that collates the horizontal and vertical parities included in the input parallel data is further provided.

In the digital line terminating device of the above embodiment, when the parity matching circuit detects an error in the parallel data by the parity matching, it controls the SOH inserting section to insert a section overhead indicating error detection in the parallel data. A parity error control unit may be further provided.

[0009]

The present invention will be described below with reference to the drawings. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is FIG.
FIG. 3 is an explanatory diagram of parity generation in the digital line terminal device of FIG.

First, the digital line terminal 100 shown in FIG.
Describing the downstream operation of the optical signal, the optical signal applied to the optical input terminal 1 is converted into an electrical signal (serial data) by the optical / electrical conversion unit 2 and further input to the serial / parallel conversion unit 3 to output W. It is converted into parallel data having a bit width (which will be described as an 8-bit width in this embodiment). At this time, the horizontal / vertical parity generation unit 23 built in the serial / parallel conversion unit 3 adds 1 bit of vertical parity and 8 bits of horizontal parity to the parallel data and sends it to the SOH terminating unit 4.

Here, the horizontal parity is the transmission data N.
It is generated and sent once per byte. The law of horizontal and vertical parity generation is shown in FIG.

The SOH terminating unit 4 checks the horizontal and vertical parity of the parallel data received from the serial / parallel converting unit 3 by the built-in horizontal / vertical parity collating unit 24, and checks the presence / absence of an error for the parity error control unit 11. Send to. Hereinafter, similarly, between the SOH terminating unit 4 and the POH terminating unit 5, and between the POH terminating unit 5 and the POH inserting unit 6
Between the POH insertion unit 6 and the SOH insertion unit 7 and between the SOH insertion unit 7 and the parallel / serial conversion unit 8 respectively, the horizontal / vertical parity generation unit 23 having the above-described constituent elements incorporated therein.
Further, the parity matching unit 24 performs horizontal / vertical parity generation and matching to detect an error, and sends the detection result to the parity control unit 11. The parity error control unit 11 inspects the information from each of the components 4 to 8 for performing the parity check, and inserts an error notification signal into the signal sent from the optical output terminal 10 when an error is detected. A control signal is sent to the SOH insertion unit 7. The SOH insertion unit 7 receives the POH based on this control signal.
A section overhead indicating an error occurrence is inserted in the parallel data from the inserting unit 6. Further, since the parity error control unit 11 also inserts an error notification in the signal sent from the optical output terminal 22, the parity error control unit 1
Error notification is given to 2.

Next, the upstream direction will be described. Similarly to the downstream direction, the optical signal applied to the optical input terminal 13 in the upstream direction is converted into an electrical signal (serial data) by the optical / electrical conversion unit 14 and further input into the serial / parallel conversion unit 15. It is converted into parallel data having a W bit width (which will be described as an 8 bit width in this embodiment). At this time, 1 bit of vertical parity and 8 bits of horizontal parity are added to the data by the horizontal / vertical parity generation unit 23 incorporated in the serial / parallel conversion unit 15 and sent to the SOH termination unit 16.

Here, the horizontal parity is the transmission data N.
It is generated and sent once per byte. The parity generation law is similar to that shown in FIG.

The SOH termination unit 16 has a built-in horizontal / vertical parity matching unit 24 for the received parallel data.
Then, the horizontal and vertical parity is checked and the presence / absence of an error is sent to the parity error control unit 12. Hereinafter, similarly, between the SOH terminating portion 16 and the POH terminating portion 17, between the POH terminating portion 17 and the POH inserting portion 18, and between the POH inserting portion 18 and the SOH.
Between OH inserts 19 and parallel to SOH inserts 19
Even between the serial conversion units 20, horizontal / vertical parity is generated and collated to detect an error, and each of the components 16 to 20 that performs the parity collation sends the error detection result to the parity control unit 12. The parity error control unit 12
Information from each section is inspected, and if an error is detected, a control signal is sent to the SOH inserting section 19 to insert an error notification signal into the optical signal sent from the optical output terminal 22. . The SOH insertion unit 19 inserts the section overhead based on this control signal into the parerell data from the POH insertion unit 18. The parity control unit 12 also inserts an error notification into the signal sent from the optical output terminal 10, so the parity error control unit 11
Error notification to.

[0016]

As described above, according to the present invention, horizontal / vertical parity generation and collation functions are added to each functional element for digital signal processing of electric signals of parallel data,
Since an error in the data transmitted between the functional elements is detected by these parity checks, there is an effect that a failure occurring in the device can be detected and the reliability of the device can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of parity generation in the embodiment of FIG.

FIG. 3 is a block diagram of a conventional digital line terminal device.

[Explanation of symbols]

1,13,25,35 Optical input terminal 2,14,26,36 Optical / electrical converter (O / E) 3,15,27,37 Serial / parallel converter (S / P) 4,16,28, 38 SOH termination section 5, 17, 29, 39 POH termination section 6, 18, 30, 40 POH insertion section 7, 19, 31, 41 SOH insertion section 8, 20, 32, 42 Parallel / serial conversion section (P / S ) 9, 21, 33, 43 Electric / optical conversion unit (E / O) 10, 22, 34, 44 Optical output terminal 11, 12 Parity error control unit 23 Horizontal / vertical parity generation unit 24 Horizontal / vertical parity comparison unit 100 , 101 Digital line terminator

Claims (3)

[Claims] 1. An optical / electrical conversion unit for converting a first optical signal into a first electric signal in a serial format, and at least one digital signal processing for converting the first electric signal into parallel data. Further, a digital signal processing unit for converting the parallel data after the digital signal processing into a second electric signal in a serial format, and a second electric signal for converting the second electric signal into a second electric signal.
In the digital line terminating device provided with an electric / optical conversion unit for converting into an optical signal of, the digital signal processing unit is provided for each functional unit of the digital signal processing on the output side of the functional unit to perform horizontal and vertical parity. A digital line terminating device comprising: a parity generation unit that generates the parity; and a parity collation unit that is provided on the input side of the functional unit and that collates the horizontal and vertical parities. 2. An optical / electrical conversion unit for converting a first optical signal input from an external circuit into a serial-type first electric signal, and a serial / electrical conversion unit for converting the first electric signal into parallel data. A parallel conversion unit, a SOH termination unit that terminates the section overhead of the parallel data, a POH termination unit that terminates the path overhead of the parallel data from the SOH termination unit, and a path overhead that is generated from the POH termination unit. POH insertion part to be inserted into the parallel data, SOH insertion part to generate SOH to be inserted into the parallel data from the POH insertion part, and parallel data from the SOH insertion part to a second electric signal in a serial format. A parallel / serial conversion unit for converting, and an electric / electrical unit for converting the second electric signal into a second optical signal and outputting the second optical signal to an external circuit. An optical conversion unit, wherein each of the serial / parallel conversion unit, the SOH termination unit, the POH termination unit, the POH insertion unit and the SOH insertion unit outputs horizontal and vertical parity to the parallel data to be output. A parity generating unit to be inserted is further provided, and each of the SOH terminating unit, the POH terminating unit, the POH inserting unit, the SOH inserting unit, and the parallel / serial converting unit is included in the input parallel data. And a parity collating unit for collating vertical parity. 3. A parity error control unit for controlling the SOH insertion unit to insert a section overhead indicating error detection into the parallel data when the parity matching circuit detects an error in the parallel data by the parity matching. The digital line terminating device according to claim 2, wherein