KR920002211B1 - Isdn telephone - Google Patents

Abstract

The ISDN telephone is connected to S-interface to provide audio service without degradation of communication quality. The ISDN telephone includes: a line interface unit (1) for processing activation/deactivation and AMI code, for reconstructing clock signal and for rearranging frames; a data link control unit (2) for detecting flags, for inserting and removing zero, for checking address, and for allowing D-channel to have priority; a B-channel control unit (3) for exchanging B-channel and for assigning B1-or B2 channel; and an audio interface unit (5) for converting audio signal from analog to digital, for processing digital signal, for generating various tone and ringer signal and for adjusting signal gain.

Description

ISDN phone

1 is a block diagram showing the overall configuration of the present invention.

2 is a block diagram showing a configuration of a line interface unit of the present invention.

3 is a structural diagram of an “S” frame of a line interface unit for connection of the present invention.

4 is a circuit block diagram for detecting the input-output interface unit keypad of the present invention.

* Explanation of symbols for main parts of the drawings

1T: Transmitter 1R: Receive

The present invention relates to an ISDN telephone which provides the most basic and popularized voice communication service by connecting to the “S” interface among ISDN units based on the integrated provision of various various services.

The importance of terminals in determining the characteristics of services in ISDN offering various services is indisputable, and therefore is currently matched with terminal capable (TE) or existing terminals with ISDN capabilities in parallel with the development of ISDN network-related components. The development of function (TA) is greatly active and its development can be promoted separately from the development of network-related devices provided by the network provider. International standardization work on the realization of services is being completed and is recommended in Recommendations I. 430, I. 440 and I. 450.

On the other hand, since ISDN terminal is integrated service and digital multiplexing method in subscriber's house, it is necessary to define data link configuration and signal processing function, user side call information and message control procedure according to this regulation. By configuring the system, compatibility with all CCITT standard subscriber access devices and exchanges can be maintained. In addition, the necessity is recognized in order to avoid external subordination and achieve technical independence when anticipating changes in standards or adding new services in the future, and in accordance with the recommendations of the CCITT under the national ISDN implementation plan, we have established domestic standards. Proposals for the digital phone standardization and its development were carried out and actual system production was required to support this.

An object of the present invention is to provide an ISDN telephone which provides various services to subscribers without degrading existing call quality as a terminal device (TE) which provides the most basic and frequently used voice service among ISDN services according to the above requirements. In order to achieve the above object, the present invention provides a 4-wire connection function for start-and-stop processing, a start / stop processing function, a 100% AMI code processing function, and a clock recovery by being connected to a XS interface. Line interface means for performing DPLL function and frame rearrangement and recovery function, connected to the line interface means for flag detection and generation function, zero insertion and removal function and FCS processing function for error detection. And data link control means for performing address checking and D channel priority control. Connected to the B channel control means, the A / D and D / A conversion functions of the voice signal, the digital signal processing function, the various tones and the like. Audio interface means for performing the function of generating the stop and adjusting the readout of the signal and filtering the filter; connected to the audio interface means for displaying various information and status, hook on / off control, ironing control, and hand cell control. Input / output interface means for performing the function, which is connected to each of the means for the overall control of all the functions, the layer 1 to layer 3 related software program processing function, the interrupt processing function, the monitoring function and the transmission and reception of information through the D channel System control means and the transport of the S interface in the power supply system based on the standard of the S interface Power control means connected to the DC-DC conversion function and the 5V output function from the 10V to 60V input and the polarity inversion during power supply of the emergency state of the network, to report to the system control unit 4 and to perform the overvoltage protection function Characterized in that the configuration.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing the overall configuration of the present invention, where (1) is a line interface unit, (2) is a data link control unit, (3) is a B channel control unit, (4) is a system control unit, and (5) Denotes an audio interface unit, 6 denotes an input / output interface unit, and 7 denotes a power supply control unit. As shown in the figure, the network access criteria of the present invention should be accessible to the “S” reference point, and the “S” interface specifications such as the frame configuration and electrical characteristics may be defined in accordance with CCITT I.430 as follows. Has a configuration. The interface structure is ＂2B + D＂ (B = 64Kbps, D = 16Kbps), and 4 wires composed of T-line (transmission) and R-line (reception) with metallic balanced cable as transmission medium Point-to-point connection to connect one TE (Terminal Equipment) from NT (Network Termination) and point to multi-point to connect up to 8 TE (Terminal Equipment) In the case of a short passive bus structure, the transmission distance is about 200m when the bus impedance is 150 and about 100m when the 75 is 75. TE connection code is limited to within 10m and NT connection code to within 13m. The extended passive bus is a structure for accommodating a plurality of TE groups which are far from the NT. The length of the track is 100m to 1000m and the distance between the TEs is standardized to 25m to 50m. For point-to-point connections, the distance between NT and TE is around 1000m. In this case, the length of the connection cord is allowed up to 25m. Here, in order to enable point-to-point connection, when multiple terminals simultaneously transmit pulses on the bus, the output impedance of the drive may be reduced to reduce the change of pulse level on the bus. It must be (low) impedance. In addition, when the signal is not output high impedance should be maintained so as not to affect the output pulse of the other terminal. In addition to the above-mentioned physical configuration conditions, the “S” interface standard has a transmission channel of 192 Kbps, a transmission code of 100% AMI code, a frame configuration of 48 bits / frame, and a digital channel start / stop and echo bit check D channels. It has electrical conditions with control and high impedance input and output impedance, 0.75Vpp output voltage and 420mW (40V) feeding strategy. The required functions of an ISDN telephone are composed of one unit, and its components and functions are divided as follows. The line interface unit 1 is connected to the XS interface and the B channel control unit 3, the data link control unit 2, and the system control unit 4, and includes a frame formatter, an AMI / BIN code processing circuit, and a DPLL. It consists of a circuit, a Link Activation Controller, B and D Channel Selector, which consists of a frame configuration function with S, a 4-wire connection function for transmission and reception, and activation / stop. Deactivation processing, 100% AMI code processing, DPLL function for click recovery, frame rearrangement and recovery will be described in more detail with reference to FIG. 2 and FIG. The data link control unit 2 is connected to the line interface 1 and the system control unit 4, and is composed of a D-channel controller and a LAPD controller to detect and generate a flag, insert and remove a zero, and detect an error. It performs FCS (Fram Check Sequence) processing, D channel priority control function and address check. A D-channel with a 16 Kbps transmission rate is time multiplexed within the frame structure on the ＂S＂ interface, and is transmitted through this D-channel so that data is encoded using Link Access Protocol D-Channel (LAPD). The D channel may transmit end-to-end signaling or packet data of low speed. The D-channel controller generates an abort when receiving seven consecutive # 1's and reports an error state to the system controller 4. In addition, when transmitting, it inserts '0' bits to check the contents of the frame between the opening flag and the closing flag so that the flag does not repeat within the frame boundary of the frame. It examines the frame contents between the opening flag and the closing flag and automatically removes the 0 bits immediately following the 5 consecutive 1s. The B channel control unit 3 is connected to the line interface unit 1, the audio interface unit 5, and the system control unit 4, and is composed of the B1 and B2 channel selectors and the B1 and B2 channel switches. Function to allocate 64Kbps B channel from the line interface unit 1 to the B1 channel or the B2 channel from the system controller 4 to perform the B2 channel allocation function. Do this. However, the D channel is directly transmitted to the data link control unit 2 via the line interface without passing through the B channel control unit 3. The system control unit 4 is connected to the line interface unit 1, the data link control unit 2, the B channel control unit 3, the audio interface unit 5, and the input / output interface unit 6, and one-chip 8 bits. It consists of a microcomputer, 62K ROM, 32K RAM, decoder logic, system clock, and peripheral I / O logic to provide total control of all functional parts of ISDN phones, as well as Layer 1, Layer 2, It has a function of processing layer 3 related software program, and receiving and processing D channel data information from data link control unit 2 or sending necessary transmission data to data link control unit 2 and real time interrupt. And manages and operates all states generated from the input / output interface 6. In addition, the one chip 8-bit microcomputer used in the present invention is the most common and generalized at present, low power consumption using CHMOS technology, ROM and RAM, oscillation and clock circuit, two 16-bit timer / counter, One full-duplex serial port is built in and has 32 input / output limes. The audio interface unit 5 is connected to the B channel control unit 3, the input / output interface unit 6, and the system control unit 4, and has an A / D converter, a D / A converter, a low pass filter, and a high pass filter. (High Pass Filter), Ring Generator and Tone Generator to convert digital signal of voice input from B channel controller 3 into analog signal (D / A conversion) or input / output The analog voice signal input from the handset of the interface unit 6 is converted into a digital signal (A / D conversion), and the encoding, decoding, signal gain adjustment, and filter functions are performed using digital signal processing techniques. In addition, a handset earpiece, a hand-set mouthpiece, a loud speaker, and the like can be connected to the audio interface unit 5, and ringing tones using digital signal processing techniques. Functions for generating various tone signals such as tone, dial tone, busy tone and ringback tone are also included. The input / output interface unit 6 is connected to the audio interface unit 5 and the system control unit 4, and has an LCD, a hook on / off switch, a hand set, a dial button, It consists of a speaker and can optionally configure a monitor terminal to test or monitor the system. In this case, the LCD has a function to visually observe or check various information and status required by the user, the hook on / off switch determines whether to use the ISDN telephone, and the hand cell (hand set) is a transmitter and receiver. It converts the sound signal into an electrical signal, and converts the electrical signal into a sound signal. In addition, the speaker is used as a telephone set loud speaker that can generate a ringing tone or allow several people to listen at the same time, and a dial button is used to talk. It is responsible for entering the other party's number address. The circuit for detecting the dial digit value in the system controller 4 when the keypad (push button) is driven will be described in detail with reference to FIG. The power supply control unit 7 can be connected according to the power supply method according to the ＂S＂ interface standard, and basically has a function of providing a rated voltage of 5V by receiving a pressure voltage of 10V to 60V, especially when supplying emergency power of the network. It uses the polarity inversion detection function to report the result to the system control unit 4 to take the necessary action and to perform the high voltage protection function. to be.

2 is a block diagram showing the configuration of the line interface of the present invention, in which 10 is a binary / pseudo ternary coder, 11 is a line driver, 12 is a differential receiver, and 13 is a frame recovery circuit. 14 denotes a bit timing recovery circuit, 15 denotes a slicer, and 16 denotes a decoder. As shown in the drawing, the line interface unit 1 has one independent transformer in the transmission and reception directions, respectively, and is connected to the ＂S＂ interface by four wires, and the receiving portion 1R is a differential receiver (12). ), A bit timing recovery circuit 14, a slicer 15 for detecting a high mark and a low mark, and a pseudo signal received with the frame recovery circuit 13 for frame synchronization. It consists of a decoder (16) that converts the ternary code (psendo-ternary code) to binary code (collision detection) so that several TE (Terminal Equipment) can be connected to the same "S" interface : Compare E bit and D bit). The transmission portion 1T of the line interface unit 1 is composed of a binary / pseudo-ternary coder (10) and a line driver 11 to mainly produce a binary code. It converts the signal into a pseudo-ternary code and induces a signal to meet the S interface standard. In addition, the line interface unit 1 may be connected to a point-to-point or point-to-mulitipoint according to a reference point, and the interface connector at this time is a CCITT. ISO DIS 8877 was established and provisionally recommended by ISO in 1985, based on the revision of the standard to ISO. The pin arrangement of this connector is used 3-6 for transmitting and receiving. Pin assignments are shown in Table 1 below.

TABLE 1

Pseudo-ternary coding is used for both transmission and reception on the 'S' interface, where '1' in binary code is represented by space (OV), and the sequence of uncontiguous '0' in binary code is used. Denotes a mark with a different polarity to reduce the DC offset on the line, and a mark of the same polarity repeated is defined as a code violation and is used to identify the frame boundary. In addition, the line interface unit 1 configures the 'S' frame to conform to the 'S' interface standard, which will be described with reference to FIG. 3. The line interface 1 configured as described above constitutes a 'S' frame used for transmission and reception, is responsible for transmitting and receiving information (INFO) for the start / stop processor, and processes 100% AMI line code processing and clock recovery. It performs DPLL function and frame arrangement function for.

FIG. 3 is a structure of a ＂S＂ frame applied to the line interface unit 1 of the present invention. FIG. 3a is a reception frame format from NT (Terminal Termination) to TE (Terminal Equipment), and FIG. 3b is from TE to NT. Transmission frame format. F is a framing bit, L is a DC balancing bit, D is a D channel bit, E is a D echo channel bit, and a FA is an auxiliary framing bit. Framing bit, N is FA bit (N = FA binary value), B1 is bit 1 of channel B, B2 is bit 2 of channel B, A is bit used for activation, S1 and S2 Denotes the evi bits for normalization, respectively, and there is a 2-bit offset between transmit and receive frames and is allocated 250 ms per 48 bits. In addition, the transmission and reception direction modes are composed of 48 bits / frame, 20 frames / multiframe and a “2B + D” multi-channel structure and a frame having a channel standardization rate of 8 KHz. In all the same.

4 is a block diagram of a circuit for detecting an input / output interface keypad according to the present invention. In the drawing, reference numeral 61 denotes a keypad (push button), 62 denotes a key encoder roll, and 63 denotes a key bounce mask. Mask, 64 denotes an oscillator roll, and 4 denotes a system control unit, and the keypad 61 uses a 4x4 pushbutton, and the key encoder 62 assigns the four rows and four columns of the keypad. Three input terminals of Y to Y4 and X1 to X4 and A, B, C, D and DA as the output terminals, and the key bounce mask 63 and the oscillator 64 are connected by the key encoder 62. This allows the keypad to detect the dial digit value in the system controller 4. When the digit generated by the keypad 61 passes through the key encoder 62, the key encoder 62 Informs the system control unit 4 that the data is useful when the key value is present. System control unit 4 to recognize this state, reads a key data value over the data bus. In addition, the state periodically at every 50ms monitored to detect whether the key data is present.

The use of the present invention as described above provides a variety of services without compromising the existing call quality in providing the most basic and frequently used voice service of the ISDN service greatly contributes to the realization of a comprehensive ISDN implementation plan .

Claims (5)

It is connected to S interface to perform S frame configuration function, 4-wire connection function for transmission and reception, start / stop processing function, 100% AMI code processing function, DPLL function for clock recovery and frame rearrangement and recovery function. A line interface means 1, connected to the line interface means, flag detection and generation function, zero insertion and removal function, FCS processing function for error detection, address confirmation and D channel priority control function Data link control means (2) for performing the following, B channel switching means (3) for connecting the B channel switching function and B1 and B2 channel assignment functions, connected to the line interface means, and the voice signal connected to the B channel control means. Audio interface means (5) for performing A / D and D / A conversion functions, digital signal processing functions, various tone and ringer generation functions, signal gain adjustment and filter functions Input / output interface means (6) connected to the interface means for displaying various information and status, hook on / off control function, dialing control function, and hand cell control function, connected to each means to control all the functions collectively A system control means (4) which performs a function to perform a function, a software program processing function related to layers 1 to layer 3, an interrupt processing function, a monitoring function, and a function of transmitting and receiving information through the D channel, and a power supply method based on the standard of the S interface. A DC-DC conversion function and a 5V output function from a 10V to 60V input and a polarity inversion in case of emergency power supply to the network, and reporting to the system controller 4 within the S & S interface. ISDN telephone, characterized in that composed of power control means for performing the overvoltage protection function (7). 2. The ISDN as claimed in claim 1, wherein the line interface means 1 connects the S-interface with four wires by applying one independent transformer to each of the transmitting portion 1T and the receiving portion 1R. cellphone. The binary / pseudoternary coder (10) connected to the B channel and the data link control unit, and the binary / pseudo3. ISDN telephone, characterized in that it consists of a line driver (11) connected to the binary coder. 3. The receiver of claim 1 or 2, wherein the receiving portion (1R) comprises a differential receiver (12) connected to a XS interface, a bit timing recovery circuit (14) connected to the differential receiver (12), and the differential receiver. (12) and a slicer (15) connected to said bit timing recovery circuit (14), a frame recovery circuit (13) and a decoder (16) connected to said slicer (15). The dial digit detection circuit for driving the keypad 61 of the input / output interface unit 6 is Y1 to Y4 which are assigned to the keypad 61 of the 4x4 pushbuttons and the 4 rows and 4 columns of the keypad. And a key encoder 62 having eight input terminals X1 to X4 and five output terminals DA of A, B, C, and D, a key bounce mask 63 and an oscillator 64 connected to the key encoder 62. And data buses 1 to 4 connected to the output terminals A, B, C, and D of the key encoder 62, and the output terminal DA is configured by connecting a data valid line for providing a key data useful state to the system controller. One ISDN telephone.

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