JPS62281624A - Multi-frame system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In a phase synchronized bus system comprising a plurality of terminal devices connected in parallel to a single bus from a network terminal device, a multi-frame is generated by a plurality of frames. The bits for automatic phase adjustment scheduled for each frame are configured so that the phase adjustment is performed only in some frames of the multi-frame, and the bits for automatic phase adjustment in the remaining frames are used for information transmission. It is designed to be used.

[Industrial application field]

The present invention relates to a multi-frame system in a phase synchronized bus system in which a plurality of terminal devices are connected in parallel to a single bus from a network termination device.

[Conventional technology]

An integrated service digital network (ISDN:
Intergrated 5 services Dig
italNetwork), emphasis is placed on interface technology for comprehensively providing various services through a single user network interface. In addition, the International Telegraph and Telephone Consultative Committee (CCIT)
T: International Telegraph
aph and Te1ephoneConsulta
It has also been recommended as part of the ``■ Series Recommendation Group'' in the tive Comm1ttee.

A feature of the above-mentioned recommendation by CCITT is that it is a four-wire bus connection using a pair of metallic wires for each uplink and downlink. The problem with this bus connection method is that
Since the round-trip propagation time from the network termination device to each terminal device differs, it is necessary to limit the bus length.

For this reason, the CCITT recommendation limits the bus length to approximately 150 m. In order to ease this bus length restriction,
As shown in the figure, a delay circuit is provided in each terminal device (21, 22-...-) connected to the network termination device (1) to adjust the delay time within each terminal device. A phase-locked bus system was proposed. In this phase synchronized lotus system, each terminal device (21, 22...
・) is equipped with one delay line in
By detecting monitor echo bits (m bits) that are looped back from the network termination equipment side to the terminal equipment side, the round-trip propagation delay time (2Tpi + Tdi
: Tpi...-----Propagation time, Td
The delay time within each terminal device is adjusted so that the delay time within each terminal device is constant.

Note that FIG. 5 is a frame configuration diagram in the above phase synchronized bus system. The transmission speed of this interface is 19
It is composed of 2kHz and 48 bits per frame. In addition, the information capacity includes the B1 channel (64kb/s) and B2 channel (64kb/s), which are information channels corresponding to the signal to be transmitted, and the signal channel for services such as sending dial signals, simultaneous communication, and signal processing. In addition to the 144 kb/s D channel (16 kb/s), there are 5 spare bits (4 kb/s) that can be used for communication.
).

The 16 kb/s D channel mentioned above uses a variable length common line signaling system that allows multiple terminal devices to transfer signaling. It allows devices to be connected in a bus format. Further, the above-mentioned spare bit S is a bit that can be communicated only from the network terminal device side to the terminal device side.

[Problem that the invention seeks to solve]

In the conventional phase-locked lotus system described above, ′! ! 4
Bidirectional communication between the terminal device and the terminal device is performed using three channels excluding the S channel, and the information capacity is (64kb/
s (information) + 64kb/s (information) + 16kb/s
(signal)) at 144 kb/s, and there was a problem in that two-way communication using the S channel between the network termination equipment and the terminal equipment was not possible.

The present invention increases the number of channels and information capacity by configuring multiframes in a phase synchronized bus system, and also enables bidirectional communication between the network termination device and the terminal device 1 using monitor bits and echo bits. The purpose is to provide a frame method.

[Means for solving problems]

As shown in Figure 1, frames are made into multi-frames by using N bits based on CCITT recommendations, and monitor bits (M bits), which are automatic phase adjustment bits, are sent from the terminal equipment side to the network termination equipment side. After receiving “0” in the above N bit, the next frame is sent for i frames, and the remaining (n-i) frames are S
Sends data as a channel and w4v! The monitor echo bit (m bit) to be sent from the end device side to the terminal device side is sent after sending "0" to the above N bit, and from the next frame onwards, it is sent for i frames, and the remaining (n-
i) Data is sent as an S channel between frames.

[For production]

The network terminal device uses the above N bits to construct a multiframe, and the terminal device receives the first "0" of these N bits to identify it as a multiframe and transmits it to the network. Since information can be sent to the terminal device using a monitor bit, the information capacity can be increased and '! Av! : Bidirectional communication is possible between the end device and the terminal device using channels other than B 1 , B2, and D channels.

〔Example〕

An embodiment according to the present invention will be described below.

Frames are made into multi-frames by using N bits (bits that are always "1" in each frame) based on the CCITT recommendation, but here, the multi-frame is made up of 4 frames as shown in Figures 2 and 3. Let me explain the case.

On the network terminal equipment side, in order to indicate that it is a multi-frame, N bits are set to "0, 1° 1.1.0..." for each frame.
1, 1.1". Then, on the terminal device side, if "0" is received in the above N bit, it identifies that it is a multi-frame and transmits the monitor bit (
M bit). Note that in other cases, the terminal device transmits a spare bit (S bit).

Therefore, in Figure 2 (al is the TE received frame, and to indicate that it is a multi-frame, the N bit inserted in the #0 frame should originally be “1” but is changed to “0”). This TE received frame is input to the decoder 31 in the terminal device shown in FIG. The clock input terminal (CLK) of the first flip-flop 32 is supplied with the N-bit read clock shown in FIG. ) is read out and output. Note that the output (Q) of the first flip-flop 32 is such that the N bit is “0”.
”, it changes from “1” to “0” and is supplied to the − data input terminal (D) of the second flip-flop 33. is provided with an N-bit read clock shown in Figure 2 (C1), which is similar to the first clock described above.
The clock is delayed by half a frame from the clock supplied to the flip-flop 32 of the clock. The output (Q) of the second flip-flop 33 becomes "0" when the N-binode is "0", and this is sent to the select terminal (S) of the selector 34 as a switching signal shown in FIG. 2(d). ). In the selector 34, based on the switching signal from the second flip-flop 33 supplied to the select terminal (S), if the switching signal is "1", the S of the A input is
If the bit is "0", the M bit of the B input is selected and sent to the network terminal equipment side via the transmission multiplexer 35 as a TE transmission frame shown in FIG. 2(Q).

As mentioned above, the terminal device is configured to transmit the M bit in the next frame if it receives "0" in the N bit in the received frame, and to transmit the S bit in other cases. It has become. Therefore, if we decide to perform the above (7) automatic phase adjustment using M hits once every 4 frames,
In other frames, an amount corresponding to the M bits is left over, and this amount can be used to transmit information. By doing this, on the M4 terminal device side, it is sufficient to transmit the m bit (monitor echo bit), which is a response to the above M bit from the terminal device side, only once every 4 frames. Between the other three frames that make up the network, in addition to the conventionally prepared S bits, an additional 81 bits are inserted in place of the above m bits, and these are passed from the network termination equipment side to the terminal equipment side. It becomes possible to send. In addition, the above m
The bit is an echo bank from the network terminating device that indicates that the terminal device is operating in the correct phase. The bits are sent to the terminal device.

According to the embodiment of the present invention described above, the S channel speed is 3 kb/s per multiframe from the network terminating device side to the terminal device side, and 9 kb/s per multiframe from the terminal device side to the network terminating device side. Information capacity can be increased.

〔Effect of the invention〕

According to the present invention described above, by configuring a multi-frame, it is possible to increase the number of channels and information capacity, as well as bidirectional communication (
(Network termination device - terminal device)), and can be used for low-speed data transmission and reception, extension communication using the S channel, etc.

[Brief explanation of drawings]

FIG. 1 is a frame configuration diagram according to the present invention, FIG. 2 is a waveform diagram for explaining an embodiment, FIG. 3 is a configuration diagram showing an embodiment of a terminal device to which the present invention is applied, and FIG. 4 is a phase synchronization diagram. A diagram of the principle of the bus system, FIG. 5 is a frame configuration diagram of the phase synchronized bus system. l...Network termination device, 21.22...Terminal device.

Claims (1)

[Claims] From the network terminal device (1) to the terminal devices (2_1, 2_2...
...) includes a certain level of N bits in the frame synchronization signal and a monitor echo bit (m bits) in the information transmission section, and also includes a frame transmitted from the terminal device to the network termination device. monitor the echo bit (m bit) in the terminal device (2_1, 2_2...) including the monitor bit (M bit), and check whether the monitor bit has been sampled in the network terminating device (1); In the phase synchronized bus method, which controls the transmission timing in the terminal device until it is returned as a monitor bit or an echo bit, during the above bidirectional transmission, a multiframe is constructed with n frames as one set. Then, the N bits of the i-frame in this multiframe sent from the network terminal device (1) to the terminal devices (2_1, 2_2, etc.) are set to a predetermined value.
0", and for the remaining (n-i) frames, the above N bit is set to "1" to indicate multi-frame, and from the next frame in which the above N bit is set to "0", the i-frame is transmitted. During this period, the above m bits are used as predetermined monitor echo bits, excluding this i frame period (n
-i) During the frame period, these m bits are used as bits for information transmission, and the above-mentioned multi-bits are sent from the terminal devices (2_1, 2_2...) to the network terminal device (1). N in the frame
The M bit is used as a predetermined monitor bit during the i-frame period after receiving a frame in which the bit is "0", and is used as a bit for information transmission during the remaining (ni) frame periods. A multi-frame method featuring