JPH03112234A - Information transmission equipment - Google Patents

Abstract

PURPOSE:To dispense with a twist pair line conversion unit and an AUI(access unit interface) cable and to inexpensively and easily perform construction by performing bidirectional communication between a concentrator and a terminal via a pair of twist lines, and transmitting collision detection information to the terminal. CONSTITUTION:When data for communication are sent from plural terminals 6 and the collision of the data occurs at a coaxial cable 1, the collision of the data is detected with the data collision detecting part of a transceiver 2. A collision signal is received with the data collision signal reception part of the concentrator HUB 4 via the AUI cable 3. And it is converted to a specific code at a conversion part, and is transmitted from the collision signal reception part to the two lines of the pair of twist lines 5. The terminal 6 converts a transmitted specific code with the conversion part, and reproduces a data collision signal, and a recognition part recognizes the collision, and re-sends the data for communication from a data transmission part. As a result, it is possible to dispense with the twist pair line conversion unit and the AUI cable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information transmission device using rice pair lines, and is used in a C3MA/CD type low power area network. be.

[Prior Art] Conventionally, in-house communication networks called local area networks (LANs) have been widely used5 for comprehensively communicating information within the premises5, especially I,E EE802.3.
Ethernet-type private communication networks that comply with standards are widely used. This Ethernet-type local area communication network has a bus-type topology in which multiple terminals are connected to a two-wire transmission line such as a coaxial cable.
e Multiple Access Ss/Co1
Access is performed using the Detection method. In the C3MA/CD system, the sending terminal first senses the state of the transmission line, and after confirming that no packets are being sent to the transmission line, sends out its own packet. If there is a packet on the transmission line, it waits until the previous packet has been sent before sending out its own packet. It constantly senses the transmission line even while sending to packet 1, and if a signal different from the signal it sent appears on the transmission line, it determines that packet I has been destroyed and starts retransmitting the packet.

Figure 11 shows C S conforming to the IEEE802.3 standard.
A conventional example of an MA/CD type local area network is shown. A terminal 6 is connected to a transceiver 2 connected to a coaxial cable 1 via an AUI cable 3. (2) As shown in FIG. 2, the transceiver 2 includes a data transmitter 21, a data receiver 22, and a data collision detector 23. AUI cable 3 is AUI (
Access Unit Interface) cable is used, and the length is up to 50 m.
There are 2 wires for reception, 2 wires for collision detection, and 8 wires including the power supply, so the number of wires is large. Usually, the number of terminals 6 that can be connected to one l transceiver 2 is 1 to 16.

Further, when one transceiver 2 is connected to the coaxial cable 1, the connection distance between the transceivers is determined to be 2.5 III, and the connections are made with an interval between them. Because of the above, the number of devices that can be connected is limited.

FIG. 12 shows another conventional example. Here, a concentrator (wire device) 4 called a HUB is connected to the transceiver 2 via an AUI cable 3, and the rice 1-pair wire 5, which is used as a telephone line, is pulled out from there, and the rice 1-pair wire The conversion unit 7 converts it into an AUI cable 8, and the terminal 6 is connected to it. This terminal 6 has a built-in LAN controller.

[Problems to be Solved by the Invention] In the system shown in FIG. 12, the versatile twisted pair wires are four wires, so two wires are used for transmission and two wires for reception. Therefore, it is necessary to provide the twisted pair line conversion unit 7 with a collision detection function using the transceiver 2, which poses a problem of increased cost. Also,
Since the twisted pair wire conversion unit 7 and the like are attached, there is a problem that the workability is poor.

The present invention has been made in view of the above points,
The purpose is to provide an information transmission device that is capable of transmitting collision detection information via a versatile twisted pair wire.

[Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, in a bus type information transmission device using a collision detection method, an H U that performs two-way communication with a terminal 6 via a twisted pair wire 5 and transmits collision detection information to the terminal 6.
It is characterized in that a plurality of terminals 6 are connected to the coaxial cable 1 via B4.

In the configuration shown in FIG. 1, the HUB 4 and the terminal 6 are directly connected via a twisted pair line 5 without using a twisted pair line conversion unit.

The collision detection information transmitted through the twisted pair wire 5 is
It is preferable to transmit information by frequency modulation, amplitude modulation or phase modulation for bidirectional communication.

[Operation 1 In the configuration not shown in FIG. 1, a coaxial cable 1 and a plurality of terminals 6
Since the to I U B 4 that connects the terminal 6 performs bidirectional communication with the terminal 6 via the twisted pair line 5 and transmits collision detection information to the terminal 6, a twisted pair line conversion unit having a collision detection function is provided. There's no need. Therefore, the cost is low and construction is easy.

[Example] FIG. 1 is a schematic diagram of an embodiment of the present invention.

A transceiver 2 is connected to a transmission line made up of a coaxial cable 1. A HUB 4 is connected to the transceiver 2 via an 8-wire AUI cable 3. HUB4
A plurality of terminals 6 are connected to the terminal 6 via twisted pair wires 5. Each of the twisted pair wires 5 connected to each terminal 6 consists of four wires.

FIG. 2 shows the configuration of the transceiver 2.

The transceiver 2 includes a data transmitter 21 that sends data to the coaxial cable 1, a data receiver 22 that receives and receives data from the coaxial cable 1, and a data collision detector 23 that detects data collisions on the coaxial cable 1. There is. This transceiver 2 is connected to the HUB 4 via an AUI cable 3 with 2 wires for transmission, 2 wires for reception, 2 wires for collision detection, and a total of 8 wires including the power supply.

FIG. 3 shows the configuration of HU B4. The HUB 4 includes a data transmitter 4 that transmits communication data, a data receiver 42 that receives communication data, a data collision signal receiver 43 that receives data collision signals from the AUT cable 3, and a data collision signal receiver 43 that receives data collision signals from the AUT cable 3. It includes a data collision signal transmitting section 44 that transmits a signal to the twisted pair wire 5, a converting section 45 that converts the data collision signal into a specific code or voltage, and a control section 46 that controls each section. Transceiver 2 AU
Communication data and data collision signals received via the I cable 3 are sent to the terminal 6 via two of the four rice wires 1 to pair wires 5, and from the terminal 6 to the four twisted pair wires. Communication data received via the remaining two lines of the AUI cable 3 is sent to the transceiver 2 via the AUI cable 3.

FIG. 4 shows the configuration of the terminal 6. The terminal 6 includes a data transmitter 61 that transmits communication data, a data receiver 62 that receives the communication data together with a data collision signal,
It includes a converting section 63 that reproduces a data collision signal received as a specific code or voltage, a data collision signal recognition section 64 that recognizes the reproduced data collision signal, and a control section 65 that controls each section.

The operation of this embodiment will be explained below. Multiple terminals 6
When communication data is sent from the AU1 cable 1 and a data collision occurs on the coaxial cable 1, the data collision is detected by the data collision detection unit 23 of the transceiver 2, and the AU1 cable 3
The data collision signal is received by the data collision signal receiving section 43 of the HU B 4 via the data collision signal receiving section 43 of the HU B 4, converted into a specific code by the converting section 45, and transmitted from the data collision signal transmitting section 44 to the two wires of the twisted pair wire 5. In the terminal 6, the transmitted specific code is converted by the converter 63 to reproduce the data collision signal, and the data collision signal recognition unit 64 recognizes the data collision.
The data transmitter 61 retransmits the communication data. In addition,
Instead of converting the data collision signal into a specific code using the conversion unit 45, it may be converted into a specific voltage. In this case,
The converter 63 reproduces a data collision signal from the transmitted specific voltage.

FIG. 5 and FIG. 6 show a HUB in another embodiment of the present invention.
4 and a block diagram of terminal 6. FIG. In this example, HU
A modulation section 40 is provided in place of the conversion section 45 of the B4, and a demodulation section 60 is provided in place of the conversion section 63 of the terminal 6. Modulation section 4
0, the data collision signal is frequency modulated, amplitude modulated, or phase modulated and transmitted together with the communication data flowing through the twisted pair wire 5. FIG. 7 shows the format of a normal signal flowing through the twisted pair wire 5, which consists of an idle ■, a preamble P, a data D, and an idle ■. FIG. 8, FIG. 9, or FIG. 10 shows a signal format when a frequency-modulated, amplitude-modulated, or phase-modulated data collision signal C is transmitted together with a normal signal by the modulation section 40, respectively. When the modulation unit 40 of the HUB 4 frequency modulates, amplitude modulates, or phase modulates the data collision signal, the demodulation unit 60 of the terminal 6 demodulates the frequency modulation signal, amplitude modulation signal, or phase modulation signal, respectively. Therefore, a data collision signal can be extracted from a modulated signal as shown in FIG. 8, FIG. 9, or FIG. 10. Also, terminal 6
Data for communication can also be transmitted normally.

[Effects of the Invention] According to the present invention, in a bus-type information transmission device using a collision detection method, two-way communication is performed with a terminal via a twisted pair wire, and a transmission line is connected via an electric wire device that transmits collision detection information to the terminal. Since a plurality of terminals are connected to each other, a twisted pair wire conversion unit and an AUI cable are not required, and the cost is low and construction is easy. Furthermore, by providing the electric wire device with a data collision detection function that was conventionally performed in a twisted pair line conversion unit, there is an effect that collision detection is reliable and signal propagation delay can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a transceiver used in the same, FIG. 3 is a block diagram of an electric wire device used in the same, and FIG. 4 is a block diagram of a terminal used in the same. 5 is a block diagram of a wire device used in another embodiment of the present invention, FIG. 6 is a block diagram of a terminal used in the same, FIGS. 7 to 10 are operational waveform diagrams of the present invention, and FIG. The figure is a schematic configuration diagram of a conventional example, and FIG. 12 is a schematic configuration diagram of another conventional example. 1 is a coaxial cable, 2 is a transceiver, 3 is an AUI cable, 4 is a HUB, 5 is a twisted pair wire, and 6 is a terminal.

Claims (5)

[Claims] (1) In a bus-type information transmission device using a collision detection method, multiple terminals are connected to the transmission line via a wire device that performs bidirectional communication with the terminals via twisted pair wires and transmits collision detection information to the terminals. An information transmission device characterized by: (2) The information transmission device according to claim 1, wherein the electric wire device and the terminal are directly connected by a twisted pair wire without using a conversion unit. (3) The information transmission device according to claim 1 or 2, wherein the collision detection information transmitted from the electric wire device to the terminal is frequency modulated. (4) The information transmission device according to claim 1 or 2, wherein the collision detection information transmitted from the electric wire device to the terminal is amplitude modulated. (5) The information transmission device according to claim 1 or 2, wherein the collision detection information transmitted from the electric wire device to the terminal is phase modulated.