KR920009341B1 - Isdn telefax terminal - Google Patents

Abstract

The terminal transmits/receives documents with high speed of 64 kbps via channel B while communicating with voice by attaching ISDN connecting function to normal teletex terminal used only in space network or packet network. It comprises a wordprocessing section (11) for editing, storing and managing documents, a teletex communication controller (12), an in/out interface section (33), an audio interface section (32), a B channel controller (34), a system controller (35), a R interface section (31) for interfacing communication wires, and an ISDN connecting section (13).

Description

ISDN teletex terminal

1 is a block diagram showing the configuration of one embodiment of an ISDN teletex terminal according to the present invention;

2 is a block diagram showing the configuration of the teletex communication module.

3 is a block diagram showing the hardware configuration of the ISDN network connection of FIG.

4 is a diagram showing a configuration of a communication protocol of an ISDN teletex terminal of the present invention.

5 is a diagram illustrating a detailed communication process of the ISDN teletex.

* Explanation of symbols for the main parts of the drawings

31: R interface unit 32: audio interface unit

33: input and output interface unit 34: B channel control unit

35 system control unit 36 line interface unit

37: data link control unit

The present invention generally relates to an ISDN teletex terminal, and in particular, a document created at the terminal together with a voice call on the ISDN can be transmitted and received to a counterpart ISDN teletex terminal using a Teletex document transmission protocol at a rate of 64 Kbps using a B channel. Relates to an ISDN teletex terminal.

The existing teletex terminal is a communication device that transmits and receives a document written in the terminal to the other teletex terminal by the OSI 7-layer protocol through a public line or a packet line, and the document communication speed of the teletex terminal is usually 2,400bps. It is very slow, and you can't talk while you're communicating.

Accordingly, an object of the present invention is to add an ISDN network access function so that a teletex terminal, which can be used only on a public line or a packet line, is connected to an ISDN network. It is to provide a channel ISDN teletex terminal that can transmit and receive.

The ISDN teletex terminal provided according to the present invention for performing the above-described object is composed of a word processor, a teletex communication control unit and an ISDN network connection unit. The ISDN network connection unit, which is an essential part of the present invention, includes an R interface unit, an input / output interface unit, an audio interface unit, a B channel control unit, a system control unit, a line interface unit, a data link control unit, and the like. Asynchronous, such as RS232C interface for D-channel, which functions as an interface for communication connection with the outside so that a line can be connected over ISDN and send / receive information with a counterpart terminal at 64 Kbps at the same time as a call. And a high speed synchronous connection unit and an S interface unit such as a B-channel RS422 interface.

The invention will now be described in more detail with reference to the accompanying drawings, using preferred embodiments.

1 shows a block diagram of an ISDN teletex provided by the present invention for carrying out the above-mentioned object, and is largely comprised of a word processor unit, a teletex communication control unit, and an ISDN network connection unit. The word processor has the function of creating, editing, and saving documents. It is a document editing function of a general workstation or a PC.

2 shows the teletex communication control unit, and includes a real time clock 25, a LAPB control unit 6, etc. in the CPU 21, the word processor connection unit 22, the ROM 23, the RAM 24, and the like. Consists of. The CPU 10 executes the teletex communication protocol while controlling the input / output (I / O) in this module by a program embedded in the ROM 23, and the word processor connection unit 22 functions to edit and store documents. It has a function of exchanging transmit and receive documents while sending and receiving commands with a word processor unit having, and the ROM (23) and RAM (24) is a memory for storing the transmit and receive document information while sending and receiving instructions to the CPU, real-time clock Numeral 25 is used as an interrupt source for timed and reserved transmissions. The LAPB control unit 6 is composed of a LAPB dedicated chip (WD 2511) for realizing the X.25 LAPB function, which is a second layer function of the teletex communication protocol, and has a program for controlling the LAPB.

3 is a diagram illustrating a hardware configuration of an ISDN network connection unit of a teletex terminal, wherein the R interface unit 31, the audio interface unit 32, the input / output interface unit 33, the B channel control unit 34, and the system control unit ( 35), a line interface unit 36, and a data link control unit 37. The R interface unit 31 receives transmission character information from the teletex communication control unit in a synchronous manner at a speed of 64 Kbps via the RS422 interface for the B channel, and loads information on one B channel according to the synchronization clock of the B channel control unit. Do it. The analog voice signal input from the handset through the audio interface unit 32 is converted into a digital signal, encoded, and then transmitted to the B channel controller 34, or the digital voice signal received from the B channel controller 34 is decoded. It converts into an analog signal and then outputs it to the input / output interface 33 to output it through the handset, and also has the function of generating various tones required for the telephone.

The input / output interface unit 33 is connected to a handset, a speaker, a hook switch, an audio interface, and a system controller to perform an ISDN connection function and to make a voice call through the handset, a speaker, a hook switch, and the like. The B channel controller 34 includes a B1 and B2 channel selector and a B1 and B2 channel switch. The B channel controller 34 receives a command from the system controller 35 and exchanges B channels for signal input / output with the line interface unit 36. Function and B1, B2 channel assignment function. The line interface unit 36 performs a 'S' frame configuration function, an activation / deactivation processing function, an AM1 code processing function, a DPLL function for clock recovery, a frame rearrangement and a recovery function, and the like. The data link control unit 37 is composed of a D-channel controller (I) and a LAPD controller, and performs flag check sequence (FCS) processing for flag detection and generation, zero insertion and removal, and error detection. It performs functions such as D channel priority control and address checking.

4 shows a protocol configuration of an ISDN teletex terminal. The user interface unit 7 is based on CCITT T.60, which defines the terminal capability used in the teletex service as an application layer. In the presentation layer (6), character sets and control functions for teletex services are defined. The alphabetic character control function is in accordance with CCITT T.61 and the Korean character information is in accordance with KSC 5601, which is a two-byte completion type.

The session layer 5 is in accordance with CCITT T.62, and the transport layer 4, which specifies basic transport services that do not depend on the network for telematics services, is in accordance with CCITT T.70. The network layer (3), the data link layer (2), and the physical layer (1) for connection to the ISDN network connection for transmitting character information without error over the B channel of 64 Kbps are X.25, X. 25 According to LAPB and V.35, Teletex communication control unit exists. On the other hand, the network layer, data link layer, and physical layer for accessing and transmitting information to the ISDN network are based on the I.450, I.440, and I430 series recommendations, respectively, and the function of this layer is realized at the ISDN network connection. The transmission and reception of signal information for the teletex communication control unit and the ISDN network connection are performed through the RS-232C interface for the D channel of FIG.

More specifically, the layers 1, 2, and 3 in the ISDN network connection here will be described. Layer 3 performs the call control procedure recommended in CCITT Recommendation I.450. The functions are as follows.

(1) Interface between layer 2 and teletex communication control unit, which has primitive processing related to layer 2 and information communication processing related to upper layer.

(2) Message generation and analysis for communication with network layer 3: It has the function of generating or analyzing messages related to call control and consists of essential information and optional information.

(3) Call processing: Manages outgoing and incoming signals for each state that performs 2B + D, the basic access of ISDN subscriber network, and performs call setup and release.

(4) Management of timer and call reference necessary for call processing

(5) B channel management: Manage the channel selection of B1, B2.

Layer 2 is configured to seamlessly perform the LAPD function for data link establishment as recommended in CCITT Recommendation I.440 series.

(1) Interface with Layer 1 and Layer 3: Ability to send and receive primitives associated with Layer 1 and Layer 3

(2) LAPD control: Framing / reframing of LAPD structure for configuring multiple logical links on one D channel, error detection, flow control and state maintenance, address analysis, information routing, multilinking of logical link / Demultiplexing function

(3) Timer management necessary for flow control

(4) TEI processing: It has a function to send TEI assignment request and TEI confirmation message in the unassigned state of TEI (Terminal Endpoint Identifier).

(5) Management part control: TEI management and start / stop management function.

Layer 1 performs the Layer 1 functions for access recommended in CCITT Rec. I.430 as follows:

(1) Activation and Deactivation Control: According to the primitives required by the upper layer, the actual physical line is made into the steady state power mode (startup) and the low power consumption state mode (stop), and the line state at this time is the upper layer. To pass on.

(2) Sending / Receiving Messages: As an interrupt processing driver routine, it is simply responsible for sending and receiving information with the network.

(3) Interface with Layer 2: It has a function of processing information received from the network, delivering it to Layer 2, and processing information sent from Layer 2 to transmit to the network.

5 is a detailed communication process diagram of ISDN teletex. The left side of FIG. 5 represents a transmitting side and the right side represents a receiving side teletex. If there is a sent document, the word processor requests the teletex communication control unit to send the document, including the receiving terminal's telephone number. The communication control unit makes a call setup request including the telephone number to the ISDN network connection through the RS232C interface for the D channel. The ISDN network access unit allocates one B channel for teletex document communication through the ISDN network and call setup process using layer 3 and layer 2 protocols (SETUP, SETUP ACK, INFO, CALL PROC, ALERT, CONNECT, CONNECT ACK, etc.). .

After receiving the call setup confirmation (SETUP CFM), the communication control unit reads the document in the word processor disk by DMA and transmits it to the other ISDN teletex at 64 Kbps through the B channel set by the teletex document communication frame format.

After the document is sent, communication is completed by performing call release procedures (DISC REQ, DISCONNECT, RELEASE, RELEASE CFM).

If ISDN service is commercialized in the future, ISDN phones for voice calls as well as terminals for text communication are indispensable. However, currently used information communication terminals cannot be directly connected to the ISDN network, but only through the ISDN network access device. It is possible to connect non-ISDN terminals to the ISDN network by using a terminal adapter outside the terminal.However, since the network connection device is external, it is not only troublesome to configure the device but also automatically There is no function to send or receive calls, which is inconvenient to use.

However, using the ISDN network connection part of the ISDN teletex terminal shown in the present invention has the advantage that the ISDN service is possible by accessing the ISDN network without the above-mentioned disadvantages.

Claims (1)

ISDN teletex terminal that can send and receive teletex documents created at the terminal along with voice call to ISDN teletex terminal at 64Kbps speed using B channel. When receiving a document transmission request from the word processor unit 11 and the word processor unit 11, etc., the line is connected while exchanging information such as the ISDN network connection unit and the other party's telephone number through the D channel port, Teletex communication control unit 12 for transmitting the document information to be transmitted to the B channel port at the speed of 64 Kbps to the other teletex terminal through the ISDN network connection, and handset, speaker, hook for performing ISDN telephone function. Input and output interface unit 33 and the data link control unit 37 connected to the switch, and connected to the line on the ISDN simultaneous with the call An RDN unit 31 which performs an interface function for transmitting and receiving information at a rate of 64 Kbps through a B channel of a counter ISDN terminal, and an ISDN network connection unit 13 including a high speed synchronous connection unit, an asynchronous connection unit, and an S interface unit. ISDN teletex terminal characterized in that it comprises a.

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