KR100407335B1 - Subscriber interface apparatus of key telephone system and method therefor - Google Patents

Abstract

PURPOSE: A subscriber interface apparatus and method of a key telephone system and a method therefor are provided to support handover and roaming functions and enhance a call processing service by reducing a call missing probability. CONSTITUTION: A serial/parallel converter(301) interfaces an address and data between a controller of a key telephone system and a BSI(Base Station Interface). A DPRAM(Dual Port RAM)(315) is a memory to which the key telephone system and a processor(311) of the BSI can independently access data. The processor(311) controls a general operation of the BSI. A ROM(312) stores a program for controlling the operation of the BSI. A RAM(313) temporarily stores data generated while the processor(311) performs a program. An oscillator(314) generates an operation clock of the processor(311). A clock generator(317) generates clock signals of the processor(311) and a DASL(Digital Adaptor for Subscriber Loop).

Description

Subscriber interface device and method of key telephone system

The present invention relates to a subscriber interface apparatus and method of a key telephone system, and more particularly, to an apparatus and method for interfacing with a wireless subscriber.

Generally, a key telephone system develops various kinds of function cards and uses them as one module. Each of the option cards described above is commonly connected to a control line through a platform bus. The signals included in the platform bus include an address bus, a data bus, a highway as a voice and data transmission path, a clock line, and other control signals.

One such card is a Digital Line Interface card (DLI). In the application of the digital key telephone system having the DLI, a digital key subset is connected through a transceiver of the DLI. Further, various applications such as connecting a general telephone module or connecting a data terminal module using the transceiver of the DLI can be performed. FIG. 1 shows an application example of a digital key telephone system having a DLI. In FIG. 1, the SLI (Single Line Interface Card) serves as a subscriber card for serving an analog subscriber. When a cordless telephone is to be connected to the digital key telephone system, the cordless telephone is connected to the SLI as if it is connected to a conventional telephone, and is used in parallel with the conventional telephone. That is, in this case, even if a plurality of wireless telephones are used, the key telephone system may be configured to have the same configuration as that of the ordinary telephone without a separate signal for controlling each telephone.

Today announced the Digital European Cordless Telecommunication (DECT) standard as the standard for cordless telephones enacted by the European Telephone Standards Institute (ETSI) in the cordless telephone sector currently used in Europe. The DECT standard is expected to be adopted in Korea. Therefore, when a remote terminal of the DECT standard is connected to a key telephone system for commercial use, a conventional key telephone system should be able to provide the following functions for connecting the DECT standard wireless terminal. When a plurality of DECT Base Stations (hereinafter referred to as DBSs) are connected to the key telephone system, a synchronization signal can be provided to each DBS so that the DBS can communicate in the TDMA (Time Division Multiplexing Access) . Second, you should be able to provide a way to accommodate dozens of option cards. That is, if one line is allocated on the platform bus and the necessary signals are not provided in common, the same signal can be generated in the card itself. Third, when connecting dozens of DBS modules, a connection method between the key telephone system and the DBS should be provided. In this case, a power transmission method, a voice and data transmission method, a synchronous signal transmission method, and the like are included.

It is therefore an object of the present invention to provide an apparatus and method for interfacing with a wireless subscriber in a key telephone system.

It is another object of the present invention to provide an apparatus and method for providing a synchronization signal and power required by a dozen base stations by providing a card capable of interfacing with a wireless subscriber of the DECT standard in a key telephone system.

According to another aspect of the present invention, there is provided an interface apparatus for a key telephone system, including a synchronization signal generator and a transceiver corresponding to the base stations for interfacing data between a key telephone system and a plurality of radio base stations, The synchronization signal generators generate synchronization signals of the base stations and transmit the synchronization signals through the channels of the transceivers. The base stations extract wireless synchronization signals from the synchronization signals received on the corresponding channels and transmit the wireless data .

1 is a diagram showing a connection relationship between a conventional key telephone system and subscriber telephone sets

2 is a diagram showing a connection relationship between a key telephone system and wireless subscribers according to an embodiment of the present invention;

3 is a diagram showing the configuration of a subscriber interface in FIG. 2; FIG.

Fig. 4 is a diagram showing the configuration of the clock generator in Fig. 3

FIG. 5 is a waveform diagram showing a synchronization signal between a key telephone system and a wireless subscriber in the system shown in FIG. 2. FIG.

6 is a diagram showing a configuration for generating a synchronization signal on the wireless subscriber side

2 is a block diagram of a key telephone system according to an embodiment of the present invention. The key telephone system includes a plurality of base station interfaces (BSIs) BSI1 to BSIm. Each BSI is connected to a plurality of base stations DBS1 to DBSn, And is responsible for the interface between the telephone system and the wireless terminals.

FIG. 3 is a diagram illustrating the configuration of the BSI1-BSIm in FIG. 2. The serial-to-parallel converter 301 functions to interface the address and data between the controller of the key telephone system and the BSI. The DPRAM (Dual Port RAM) 315 is a memory in which the key telephone system and the processor 311 of the BSI can independently access data. Processor 311 controls the overall operation of the BSI. ROM 312 is a memory in which the processor 312 stores a program for controlling the operation of the BSI. The RAM 313 is a memory for temporarily storing data generated while the processor 311 executes the program. An oscillator 314 generates an operating clock of the processor 311. The clock generator 317 generates a clock signal of the processor 311 and digital adapter for subscriber loops (DASL). 4 is a diagram showing the configuration of the clock generator 317. In the state where the initialization signal / reset transitions to the normal state, the frame synchronizing signal FSX is counted to generate the first clock signal and the second clock signal. Here, the clock generator 317 generates a second clock signal of 80 ms, supplies the second clock signal to the processor 311, generates a first clock signal of 10 ms, and supplies the first clock signal to the DASLs. The DASLs are connected to the DBSs and perform an interface operation between the DBS and the key telephone system. Here, two DASLs are connected to one DBS, and if one BSI can service four DBSs, eight DASL1-DASLs 8 are connected to the one BSI. A module controller 318 is connected between the processor 311 and the DASL1-DASL8, and controls the interface operation of the DASL1-DASL8. The DASL1-DASL8 may use TP3043 manufactured and sold by National Semiconductor Ducts. A UART (Universal Asynchronous Receiver & Transmitter driver) 316 forms a data path between the BSI and an external device. The device connected to the UART 316 may be a measuring device or the like.

As described above, FIG. 2 illustrates a ping-pong transceiver DASL1 for supplying power to the plurality of DBS modules (four DBS1 to DBS4 in the embodiment of the present invention) and for transmitting and receiving voice and data. A DMC (Digital Module Controller) 318 for controlling each transceiver, a clock generator 317 for generating a synchronization signal using a frame synchronization signal of an initialization signal (/ reset) . In addition, a DPRAM 315, a processor 311, a ROM 312, and a RAM 313 are provided to perform IPC (Inter Processor Communication) between the key telephone system and the BSI.

FIG. 5 shows the timing of generating a synchronization signal used in each DBS. 5, it is assumed that there are four DBS1 to DBS4, and each of the DBS1 to DBS4 generates a synchronization signal at the time of interfacing data. FIG. 6 shows a configuration for reproducing a synchronization signal received in each of the DBS1-EDBS4.

Referring to FIGS. 2 to 6, an interface operation according to an exemplary embodiment of the present invention will be described. In the key telephone system, a common signal for driving a voice and data transmitting high-level is generated. The BSI inputs a frame synchronizing signal FSx, which indicates the start of the highway, and a clock BCLK, which distinguishes each bit. The signals are supplied to all the boards so that voice and data can be transmitted from any other card. The clock generator 317 configured as shown in FIG. 3 generates the first clock signal 10 ms and the second clock signal 800 ms required for the DECT using Fsx among the signals. The clock generator 317 generates 10 ms and 800 ms using the frame synchronization signal Fsx and the / reset signal for initializing the entire card on the platform bus. That is, Fsx is counted after the / reset signal to initialize the previous card becomes normal, and 10 ms and 800 ms required for DECT are generated. The synchronization signal is generated at the same time in the plurality of BSI boards as described above.

In the embodiment of the present invention, the connection method between the DBS modules of the BSI board is a four-wire method, and two TCM transceivers are connected to one DBS. The transceiver becomes DASL1-DASL8. Since the transceivers have a transmission capacity of 2B + D capacity, they can interface with 4 subscribers' wireless subscribers at the same time through one DBS. For example, when four DBSs can be connected in one BSI, the DECT system is a multi-cell structure as shown in FIG.

In the above structure, the synchronization signal SYNC transmits control data by one of the two transceivers and transmits the synchronization signal SYNC by the remaining transceivers.

At this time, the ping-pong transceiver may not synchronize the B channel for voice transmission and the D channel for transmitting control data. In this case, when the timing of the B channel and the D channel at the time of input is transmitted to the opposite side, the timing is outputted with arbitrary timing. If the transceiver uses DASL, the above example may occur. That is, when a certain sync signal is transmitted to each DBS through one D channel in the BSI, even if transmission is performed at the same point in time, the sync signals output from the respective DBSs are different from each other, making the sync signal SYNC unusable.

Therefore, in the embodiment of the present invention, a signal for activating the DBS is generated, and a gating signal is generated so that data can be sampled and transmitted using the same clock as BCLK. In this case, the synchronization signal SYNC transmitted from the BSI is included in one frame as shown in 511-513 of FIG. Also in this case, the synchronization signal SYNC of the D channel outputted from each DBS does not coincide, and is generated as 522 and 524 in FIG. Therefore, in each of the DBS1 to DBS4, a synchronization extraction circuit as shown in FIG. 6 is provided to extract the synchronization signal SYNC. That is, the synchronization extraction circuit shown in FIG. 6 inputs a B-channel synchronization signal Fsc such as 521 and 523 as a clock and generates RFSYNC synchronized with the Fsc, and each of the DBS1-DBS4 uses a synchronization signal RFSYNC. The Fsc used here depends on the distance between BSI and DBS. As shown in FIG. 5, the difference of the B channel synchronization signal Fsc in each DBS is generated by FSdiff, and the difference of the synchronization signal SYNC transmitted through the D channel is SYNCdiff. The synchronization signal RFSYNC adjusted by the configuration shown in FIG. 6 is represented by RFSYNC1 and RFSYNC2 as 525 and 526. [

In the current DECT standard, the synchronization signal RFSYNC is defined within 4 microseconds. In the BSI, the module control unit 318 is a dedicated integrated circuit connected between the processor 311 and the transceivers DASL1 to DASL8 to perform data transmission / reception on the D channel and generate control signals required by the transceiver.

As described above, a cordless telephone of the DECT standard currently being adopted as a European standard can be applied to a key telephone system. In addition, a handover function and a roaming function can be supported to maximize the mobility of the wireless telephone, and the probability of call failure can be reduced, thereby improving the call processing service.

Claims (3)

An apparatus for interfacing data between a key telephone system and a plurality of radio base stations, the apparatus comprising: a synchronization signal generator and transceivers respectively corresponding to the base stations, wherein the synchronization signal generators generate synchronization signals of respective base stations, Wherein the base station transmits control data and a synchronization signal through different channels, and extracts a wireless synchronization signal from a synchronization signal received through the corresponding channel of each of the base stations, and transmits the wireless data to the wireless subscriber interface Device. 2. The wireless subscriber interface apparatus of claim 1, wherein the synchronization signal generator generates a synchronization signal by counting a frame synchronization signal after a system initialization signal transitions to a normal state. A method for interfacing data between a key telephone system and a plurality of wireless base stations, the interface device including a synchronization signal generator corresponding to a plurality of wireless basestations, and a transceiver, wherein the synchronization signal generators generate a synchronization signal of each base station Wherein the transceivers transmit control data and a synchronization signal to different channels and the base stations each extract wireless synchronization signals from synchronization signals received on the corresponding channels and transmit wireless data. Interface method.