JP2773572B2 - Communication device with data monitoring function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus for performing communication using a circuit switching service of an integrated digital communication network (hereinafter referred to as "ISDN line").

[0002]

2. Description of the Related Art FIG. 2 shows 64 × nkbps (n is an integer).
1 shows a configuration of a conventional communication apparatus 11 having no monitoring function for performing communication of the present invention. In FIG. 2, reference numeral 1 denotes an ISDN interface circuit, which has a layer 1 function of an ISDN line. Reference numeral 2 denotes a serial communication controller, which has a function of performing speed matching with a terminal device. 3 is a CPU,
It has a function of controlling the entire device in addition to the functions of the ISDN line, Layer 2 and Layer 3.

A parity check circuit 10 has a function of performing a parity check of data received from a terminal device. Reference numeral 4 denotes a terminal device that transmits and receives data to and from an ISDN line via the communication device 11.

Next, the operation of the above conventional example will be described.
In FIG. 2, when there is an incoming call from the ISDN line, or when the data of the terminal device 4 is transmitted from the communication device 11 to the ISDN line, the D-channel call control is performed by the CPU 3 through the ISDN interface circuit 1. Do. When the B channel is connected by the D channel call control, the B channel data is transmitted to the parity check circuit 10.
Except for the parity check, the transmission and reception are performed transparently through the serial communication controller 2 between the ISDN interface circuit 1 and the terminal device 4.

[0005]

However, in the above-mentioned conventional example, there is no means for confirming whether or not the data of the B channel is transmitted correctly, so that there is a problem that data during communication cannot be monitored. . Since transmission procedures up to layers 1 to 3 based on the OSI concept are prepared on the ISDN line, it is generally considered that transmission errors do not occur. However, when the transmission paths of the B channel and the D channel are different. In this case, there is a possibility that a failure occurs in which data on the B channel is not transmitted normally even though the D channel is operating normally. In this case, a function of monitoring the B channel data end to end is required.

The present invention solves such a conventional problem, and a communication apparatus with a data monitoring function capable of monitoring end-to-end data of B-channel data using only one bit in the data. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides means for performing a parity check using a parity bit of data transmitted from a terminal device, and synchronizing in place of the parity bit when there is no parity error. Means for inserting a frame synchronization having a pattern, means for monitoring the frame synchronization in data received from the integrated digital communication network, and means for inserting a parity bit in place of the frame synchronization in the received data. ing.

[0008]

The present invention has the following functions and effects by the above configuration. That is, in data transmission including a parity bit, a frame synchronization pattern is inserted in place of the parity bit after the parity check, and the frame synchronization is monitored, thereby enabling end-to-end data monitoring of the B channel data.

Further, by monitoring data by frame synchronization, it becomes possible to insert information other than the synchronization pattern into the frame synchronization, thereby making it possible to use an effective fee for data.

[0010]

FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 12 denotes a communication device, and reference numeral 4 denotes a terminal device for transmitting and receiving data to and from an ISDN line via the communication device 12. In the communication device 12, 1 is I
This is an SDN interface circuit and has a function of the layer 1 of the ISDN line. Reference numeral 2 denotes a serial communication controller, which has a function of performing speed matching with a terminal device. 3
Is a CPU, which is a layer 2 and a layer 3 of an ISDN line.
In addition to the functions described above, it has a control function for the entire communication device 12. 5
Is a switch in the transmission path, and has a function of switching received data from the ISDN line.

Reference numeral 6 denotes a switch on the receiving path, which has a function of switching transmission data from the terminal device 4. 7
Is a frame synchronization monitoring circuit having a function of monitoring the frame synchronization of the received data monitoring frame. Reference numeral 8 denotes a parity addition circuit, which has a function of adding parity according to the setting. A frame sending circuit 9 has a function of generating and sending a frame for data monitoring. Reference numeral 10 denotes a parity check circuit, which has a function of performing parity check of data received from the terminal device.

A transmission and reception path between the ISDN interface circuit 1 and the serial communication controller 2 includes a line memory such as a FIFO for temporarily storing data, but is not particularly related to the present invention. Description is omitted.

Next, the operation of the configuration shown in FIG. 1 will be described. In FIG. 1, when a call is sent from the terminal device 4 to the ISDN line via the communication device 12, the IS
The CPU 3 controls the D channel through the DN interface circuit 1. The B channel is connected by the call control of the D channel. It is assumed that the data to be transmitted is 8 bits and is composed of 7 data bits and 1 parity bit. In this case, the CPU
3 switches the switch 6 to the a side, and transmits the data bit to the ISDN interface circuit 1. Further, the switch 6 is switched to the b side, the parity check of the parity bit is performed by the parity check circuit 10, and when a parity error occurs, the terminal device 4 performs a reception data error process. If no parity error occurs and the frame is normal, the frame sending circuit 9 inserts a monitoring frame synchronization instead of the parity bit and sends it to the ISDN interface circuit 1 as B channel data. Violation of the coding rule in the AMI code is used as the frame synchronization.

By transmitting a monitoring frame including a synchronization pattern instead of a parity bit, information other than data check can be transmitted. In addition, other information can be inserted instead of the monitoring frame synchronization, so that data can be effectively used.

On the other hand, when there is an incoming call from the ISDN line, the switch 5 is switched to the b side to extract the monitoring frame inserted at the position of the parity bit of the received B channel data. Synchronization is detected. During data communication, synchronization is constantly monitored, and when frame synchronization loss is detected, a process of notifying the ISDN line that B channel data is abnormal is performed. Further, other information included in the frame is also extracted by the frame synchronization monitoring circuit 7. The parity adding circuit 8 adds the parity specified by the CPU 3 instead of the frame bit, and transmits the data to the serial communication controller 2.

In the case of 8-bit full data transmission without parity bits in transmitted / received data, the switches 5 and 6 are switched to the side a so that the terminal device 4 and the ISD
A transparent transmission path is formed between the N interface circuit 1 and the N interface circuit 1.

[0017]

As apparent from the above embodiment, the present invention has the following effects. That is, in data transmission having a configuration of 7 data bits and 1 parity bit, it is possible to monitor the B channel data at the end and end. Also, by performing this not by parity but by frame synchronization monitoring, other information can be added to the frame, and data can be effectively used.

[Brief description of the drawings]

FIG. 1 is a block diagram of a communication device with a monitoring function according to the present invention.

FIG. 2 is a block diagram of a conventional communication terminal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ISDN interface circuit 2 Serial communication controller 3 CPU 4 Terminal device 5 Switch 6 Switch 7 Frame synchronization monitoring circuit 8 Parity addition circuit 9 Frame transmission circuit 10 Parity check circuit 12 Communication device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04L 12/64

Claims (1)

(57) [Claims] 1. A communication device for performing communication using a B channel between a terminal device and an integrated digital communication network by a circuit switching service of an integrated digital communication network (ISDN). Means for performing a parity check using a parity bit of data, means for inserting frame synchronization having a synchronization pattern in place of the parity bit when there is no parity error, and means for synchronizing the frame in data received from the integrated digital communication network. And a means for inserting a parity bit in place of the frame synchronization in the received data.