JP2540186B2 - ISDN interface line test equipment - Google Patents

Description

FIELD OF THE INVENTION This invention is in the field of digital private branch exchanges.
The present invention relates to a line test device which is used by connecting to a line according to a user / network interface condition of "Digital Integrated Services Network" called ISDN.

2. Description of the Related Art A conventional line test device 1 is a network device 2 as shown in FIG.
And the terminal device 3 are branch-connected to a downlink 4 and an uplink 5. The network device 2 connects the frame transmission circuit 10 through the frame transmission circuit 6, the drive circuit 7, the transformer 8 and the impedance matching circuit 9 to the downlink 4
A frame receiving circuit 14 is connected to one end of the upstream line 5 via an impedance matching circuit 11, a transformer 12 and a receive circuit 13. The other ends of the downlink 4 and the uplink 5 are impedance matching circuits 15 and 1, respectively.
6 is connected. In the terminal device 3 as well as the network device 2, the frame transmission circuit 17 and the frame reception circuit 18 are provided with the transformers 19 and 2.
0, the drive circuit 21, and the receive circuit 22 are connected to the downlink 4 and the uplink 5. The line test equipment 1
The first and second frame receiving circuits 23 and 24, the transformer 25 and the receive circuit 26 for inputting the signal of the downlink 4 to the first frame receiving circuit 23, and the signal of the uplink 5 to the second frame reception It is composed of a transformer 27 for inputting to the circuit 24 and a receive circuit 28.

Since the conventional line test apparatus 1 is configured in this way, the communication of the downlink 4 from the network device 2 to the terminal device 3 and the communication of the uplink 5 from the terminal device 3 to the network device 2 is performed by the first and second communication. It can be monitored by the frame receiving circuits 23 and 24.

Another conventional line test apparatus 1 includes a frame receiving circuit 24 and a frame transmitting circuit 29 as shown in FIG. In this case, the opposite communication with the terminal device 3 becomes possible.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention With such a conventional configuration, since it is not possible to process a frame transmitted and received between the network device 2 and the terminal device 3, communication between the network device 2 and the terminal device 3 is performed. There is a problem that protocol compatibility tests cannot be performed.

An object of the present invention is to provide a line test device capable of processing a frame transmitted / received between a network device and a terminal device.

Means for Solving the Problems A line test device of the present invention is a line test device which is installed in series on an interface transmission line connecting a network device and a terminal device, and receives a signal from the network device to send a D signal. A first frame receiving circuit for frame-separating a channel and two B-channels and a timing signal; and frame-synchronizing a D-channel with two B-channels and a timing signal for receiving a signal from a terminal device. A second frame receiving circuit for separating, a first processing circuit for performing frame processing at a data link level defined by an ISDN user / network interface on the D channel signal separated by the first frame receiving circuit, and a second The D channel signal separated by the frame reception circuit of the A second processing circuit for performing a signal processing, a memory for storing the signals processed by the first and second processing circuits, and a signal processed by the second processing circuit for reading from the memory to the ISDN user Based on the timing signal separated by the first frame receiving circuit, the D channel signal subjected to frame processing at the data link level defined by the network interface and the two B channel signals separated by the first frame receiving circuit And a first frame transmitting circuit for multiplexing and transmitting to a terminal device, and a signal processed by the first processing circuit is read from the memory and frame processing at a data link level defined by an ISDN user / network interface is performed. And the two B channel signals separated by the second frame receiving circuit are separated by the second frame receiving circuit. A second frame transmission circuit for multiplexing and transmitting to the network device based on the minging signal, a first processing circuit, a second processing circuit, and a processor for controlling reading from the memory and processing for the contents of the memory are provided. Characterize.

Operation According to this configuration, the digital signal transmitted from the network device and the terminal device is taken in by the line test device which is serially interposed in the interface transmission line connecting the network device and the terminal device. The digital signal from the network device to the terminal device is
In the first frame receiving circuit, D channel and two B channels
The channel and timing signals are separated in frame synchronization, the D-channel signal is processed by the first processing circuit in relation to the LAPD frame, and then written in the memory. Then, the data read out from the memory is subjected to processing relating to LAPD, and this signal is further processed in the second frame transmitting circuit by the two B channel signals separated by the first frame receiving circuit and the first frame receiving circuit. The signals are multiplexed and transmitted to the terminal device based on the timing signals separated by.
Similarly, the digital signal from the terminal device to the network device is similarly processed through the second frame receiving circuit → second processing circuit → memory → first frame transmitting circuit and transmitted to the network device.

Embodiment One embodiment of the present invention will be described below with reference to FIG. It should be noted that components having the same functions as those of the conventional example shown in FIG.

FIG. 1 shows the line test apparatus 1 of the present invention and its usage. The line test apparatus 1 of the present invention is connected in series to the down line 4 via the impedance matching circuit 30 and the transformer 31, and the impedance matching circuit 32 and the transformer 33, and the up line 5 also includes the impedance matching circuit 34. The transformer 35 and the impedance matching circuit 36 and the transformer 37 are interposed in series. A first frame receiving circuit 39 is connected to the transformer 31 via a receive circuit 38. In the first frame receiving circuit 39, the digital signal taken in from the network device 2 is frame-synchronized with two message channels B11 and B12 called B channels, one control signal channel D1 called D channel and the timing signal CLK1. Take and separate. The channel D1 separated by the first frame receiving circuit 39 is input to the first processing circuit 40. The first processing circuit 40 processes the LAPD frame [data link level frame defined by the ISDN user / network interface] for the channel D1. The signal subjected to the LAPD frame processing is stored as a packet in the memory 41 for data buffer. The processor 42 performs arbitrary data processing on the packet read from the memory 41 in the second processing circuit 43 and inputs the packet to the first frame transmission circuit 44. In the first frame transmission circuit 44, a channel D1 ′ read from the memory 41 via the second processing circuit 43 as a signal to replace the channel D1 and subjected to arbitrary data processing, and a first frame transmission circuit 44
The channels B11 and B12 separated by the frame receiving circuit 39 are multiplexed as the original based on the timing signal CLK1,
The multiplexed signal is transmitted to the terminal device 3 via the driver circuit 45, the transformer 33, and the downlink 4. By the processor 42, the packet of the channel D1 can be deleted or a new packet can be generated.

A second frame receiving circuit 47 is connected to the transformer 35 via a receive circuit 46. Second frame receiving circuit
In 47, the digital signal fetched from the terminal device 3 includes two message channels B21 and B22, one control signal channel called D channel D2, and a timing signal CLK2.
The frame is synchronized and separated. The channel D2 separated by the love 2 frame receiving circuit 47 is input to the second processing circuit 43. The second control circuit 43 processes the LAPD frame on the channel D2. The signal subjected to the LAPD frame processing is stored as a packet in the memory 41 for the data buffer.
The processor 42 subjects the packet read from the memory 41 to arbitrary data processing in the first processing circuit 40 and inputs the packet to the second frame transmission circuit 48. In the second frame transmission circuit 48, a channel D2 ′ read from the memory 41 via the first processing circuit 40 as a signal in place of the channel D2 and subjected to arbitrary data processing, and a second frame reception The channels B21 and B22 separated by the circuit 47 are multiplexed as before based on the timing signal CLK2, and the multiplexed signal is transmitted to the network device 2 via the driver circuit 49, the transformer 37 and the upstream line 5. To be done. By the processor 42, the packet of the channel D2 can be deleted or a new packet can be generated.

As described above, according to the above-described embodiment, regarding the communication between the network device 2 and the terminal device 3, the D channel on the transmission line is processed by the line test device 1 of the present invention, the data processing, the packet deletion, and the packet transmission / reception of the packet are performed. Generation can be performed, and the compatibility test of the communication protocol between the network device 2 and the terminal device 3 can be performed very effectively.

In the present embodiment, the signals are transmitted from one side to the other side as described above because they are installed in series with the downlink 4 and the uplink 5 as the interface transmission line between the network device 2 and the terminal device 3. Can be replaced with another processed signal, a circuit can be added so that the signal can be monitored as in the conventional case, and software of the processor 42 can be processed and monitored.

The line test device 1 of the present invention is installed in series at a position called an interface with a public telecommunications network called a T point, or a private telecommunications network called a S point such as a PBX or LAN. It may be any of the interfaces with.

EFFECTS OF THE INVENTION As described above, according to the present invention, the circuit test device is provided in series in the interface transmission line connecting the network device and the terminal device, and the signal transmitted from the network device to the terminal device is provided therein. Of the signal transmitted from the terminal device to the network device in the same manner as the first system that separates the D channel signal from the Since it has two systems, the second system for processing the D channel portion, it is possible to test the compatibility of communication protocols.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the line test apparatus of the present invention, and FIGS. 2 and 3 are block diagrams of a conventional line test apparatus, respectively. 1 ... Line test device, 2 ... Network device, 3 ... Terminal device,
4 ... Down line, 5 ... Up line, 39 ... First frame receiving circuit, 40 ... First processing circuit, 41 ... Memory, 42
...... Processor, 43 ...... Second processing circuit, 44 ...... First frame transmitting circuit, 47 ...... Second frame receiving circuit, 48
...... Second frame transmission circuit.

Claims (1)

(57) [Claims] 1. A line test device which is installed in series on an interface transmission line connecting a network device and a terminal device, and receives a signal from the network device to generate a D channel, two B channels and a timing signal. A first frame receiving circuit that separates in frame synchronization; a second frame receiving circuit that receives a signal from a terminal device and separates the D channel, two B channels, and timing signals in frame synchronization; A first processing circuit for performing frame processing at the data link level defined by the ISDN user / network interface on the D channel signal separated by the first frame receiving circuit, and a D channel separated by the second frame receiving circuit Second processing for data link level frame processing specified by ISDN user / network interface for signals
Processing circuit, a memory for storing signals processed by the first and second processing circuits, and a signal processed by the second processing circuit are read from the memory and defined by the ISDN user network interface. A terminal device that multiplexes a D channel signal subjected to data link level frame processing and two B channel signals separated by a first frame receiving circuit based on a timing signal separated by a first frame receiving circuit A first frame transmission circuit for transmitting to
The signal processed by the processing circuit of No. 2 is read from the memory, and the D channel signal subjected to the frame processing at the data link level defined by the ISDN user / network interface and the two separated by the second frame receiving circuit. A second channel that multiplexes the B channel signal with the timing signal separated by the second frame receiving circuit and transmits the multiplexed signal to the network device.
Of the frame transmission circuit, the first and second processing circuits, and a processor for controlling reading from the memory and processing for the contents of the memory.