JPH01317051A - Isdn basic access subscriber terminal equipment - Google Patents

Abstract

PURPOSE:To attain simple mutual D-channel communication by providing a reception circuit receiving an E channel signal and a DD channel signal and signals of the DD and E channels, analyzing them and outputting the result to a high-order layer users application. CONSTITUTION:A frame multiplex circuit 25 of a subscriber terminal equipment TE1 applies frame multiplex between the E channel signal on a subscriber bus and a D channel signal from an exchange. Then a reception circuit 23 receives the output of the frame multiplex circuit 25 to analyze the D channel frame and the E channel frame and detects it that the specific control field of the E channel frame to be a predetermined specific data and to output the content of the frame to the high-order layer users application when the address of the incoming terminal equipment of the frame is an address of its own terminal equipment TE1. Thus, the frame having the data code on the control field given up ineffectively by the exchange is extracted. Thus, the communication between the DD channels is simplified.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ISDN basic access subscriber terminal device, particularly an ISDN basic access subscriber terminal device that enables mutual communication via a D channel under the control of the same network termination device. TECHNICAL FIELD The present invention relates to a thick access subscriber terminal device.

[Conventional technology]

In the user-network interface of I SDN basic access recommended by CCITT, as shown in the block diagram of the in-home system in Figure 3, the in-home bus has a Dυ channel that sends signals from the terminal device TE to the exchange, and a Dυ channel that sends signals from the terminal device TE to the exchange. It has a D echo channel (hereinafter referred to as an E channel) through which signals to be sent are looped back at the network termination device 1, and a DD channel which sends signals from the exchange to the terminal device TE.
The Du channel message sent from the user application 21 is passed through the D channel transmission circuit 22 and placed on the Dυ channel on the home bus as a transmission signal. On the other hand, a signal on the DD channel from the exchange is received and analyzed by the D channel receiving circuit 26, and the user application 21 is notified. Also, the signal on the E channel returned by the network terminating device 1 is compared with the signal on the Du channel transmitted, and other terminal devices TE under the same network terminating device 1 are compared.

It is specified that a contention processing circuit 24 is provided to avoid collision contention of signals transmitted to the channel.

[Problem to be solved by the invention]

Therefore, messages for the Dt+ channel sent from the terminal equipment TE according to the above regulations are always sent to the exchange, and messages on the DD channel are always received from the exchange. Even when communicating with other subordinate terminal devices TE via the D channel, it must always go through the exchange, which has the drawback of increasing traffic on the exchange and subjecting it to charges.

[Means to solve the problem]

The ISDN basic access subscriber terminal device of the present invention is an ISDN basic access subscriber terminal device installed in the premises of an ISDN basic access system subscriber terminal device, in which the E channel signal on the premises bus and the A frame multiplexing circuit performs frame multiplexing with the channel signal, receives the output of this frame multiplexing circuit, analyzes the D channel frame and the E channel frame, and analyzes the specific control field of the E channel frame in advance. A reception circuit that detects that the data is the specified specific data and outputs the contents of this frame to the upper layer user application when the address of the destination terminal device of the frame is the address of the terminal device itself. It is constituted by having.

〔Example〕

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

FIG. 1 is a block diagram of one embodiment of the present invention, including an in-home system. Terminal equipment to TEN are ISDN basic access subscriber terminal equipment capable of communication between D channels using the in-home bus of the present invention,
It is connected to the network terminal device 1 via a home bus. Terminal equipment ~ TEN are user applications 21 and D, respectively.
channel transmitting circuit 22, D-E channel receiving circuit 25,
Contention processing circuit 24 that monitors and controls contention of DU channels
and a frame multiplexing circuit 25 for frame multiplexing signals of the DO channel and the E channel.

When the terminal device TEN sends a message to the terminal device TE1 via the DU channel, the TEN user application sends a frame in a format that does not affect the exchange side, as shown in an example in FIG. 2, to the D channel transmission circuit 22. Send via. This format is fixed T
The EI field DTP, I contains the address of the called terminal equipment, the calling fixed TEI field OTE I contains the address of the calling terminal equipment TEN, and the specific control field ECF is defined as a control field in CCITT Recommendation 1.441. values that are not included, e.g. FB
(H), the EA bit (extension bit) of the first octet is set to 0, the EA bit of the second octet is set to 1, and the transmission data is set in the user data area from the fourth octet. The signal on the Dυ channel is
The signal is sent to the exchange via the network termination device 1, and is also sent back to the E channel on the home bus. The E channel signal is received by all the terminal devices to TEN under the network termination device 1, and is sent to each contention processing circuit 2.
4, it is compared with the signal output to the Dυ channel of each D channel transmitting circuit 22, and if there is a mismatch, the D
Transmission of the channel transmission circuit 22 is stopped. This avoids collision with signals sent to the Du channel from terminal devices other than the terminal device TEN. On the other hand, the E channel signal input to each of the terminal devices TE1 to TEN and the Do channel signal input from the exchange are frame multiplexed by the frame multiplexing circuit 25 and received by the D-E channel receiving circuit 23. Ru. Here, if the value of the ECF of the third octet is FB (H) in the above example, then the value of the ECF of the third octet is
The value of DTE I of the tet is compared with the address of the own terminal device, and if they do not match, this received frame is discarded, and if they match (in this example, if it is the address of the terminal device TE1), the value of the first octet is The user data from the 4th octet onwards is output to the user application 21 along with the value of the originating side fixed TEI field 0TEI. Note that no response confirmation is performed for the above discrepancies and matches. The user application 21 sets the originator fixed TEI field to 0.
The TEI value and the user data message are displayed as they are or are stored and displayed when accessed by the subscriber.

〔Effect of the invention〕

As explained above, the present invention provides an ISDN basic access subscriber terminal with a frame multiplexing circuit for E channel signals and DD channel signals, and a frame multiplexing circuit for receiving and analyzing the DD channel and E channel signals. It has a receiving circuit that outputs to the user application layer, and is deployed under the same network terminal equipment by extracting frames with data codes on the control field that are invalidated and discarded at the exchange. This has the advantage that mutual D channel communication can be carried out between a plurality of terminal devices connected to each other without intervening an exchange and without cutting the communication path with the exchange.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a block diagram of an in-home system including a conventional I5DN basic access subscriber terminal. DESCRIPTION OF SYMBOLS 1... Network termination device, 21... User application, 22... D channel transmission circuit, 23... D-E
Channel reception circuit, 24... Competition processing circuit, 25...
・Frame multiplexing circuit, 26...D channel receiving circuit,
TE, TEI~TEN...terminal device. Figure 2

Claims (1)

[Claims] A frame multiplexing circuit that performs frame multiplexing of a D echo channel signal on an in-house bus and a D channel signal from an exchange in an ISDN basic access subscriber terminal device installed in an ISDN basic access subscriber's premises; After receiving the output of this frame multiplexing circuit,
It analyzes the D-echo channel frame and the D-echo channel frame, detects that the specific control field of the D-echo channel frame is predetermined specific data, and detects that the address of the destination terminal device of the frame is An ISDN basic access subscriber terminal device comprising a receiving circuit that outputs the contents of the frame to an upper layer user application when the address is the address of the own terminal device.