GB2394859A - Operation of highway expansion apparatus for key telephone system - Google Patents

Abstract

An operation method of a highway expansion apparatus for a key telephone system, comprising: determining a transmission switch by using an output port number of a highway; determining a reception switch by using an input port number of the highway; and transmitting the highway through a route of a selected reception and transmission switches.

Description

GB 2394859 A continuation (74) Agent and/or Address for Service: Page

White & Farrer 54 Doughty Street, LONDON, WC1N 2LS, United Kingdom

HIGHWAY EXPANSION APPARATUS FOR RFy TELEPHONE SYSTEhI AND OPERATION METHOD THEREOF BACKGROUND OF TO INVENTION

1. Field of the Invention

[1] The present invention relates to a telephone system, and in particular to a key telephone system.

2. Background of the Related Art

[2] In general, a key telephone system is a small telephone exchange system for relaying telephone communication between extensions or between an extension and an outside phone by connecting plr;1 telephones with extension numbers in order to use limited telephone lines by a great number of people. The key celephonc system consists of a main device, telephone sets, lines connecting the main device with the telephone sets and an additional unit for operating the system more efficiently. [3] However, in the related err key telephone system, the system cart be limited to a mourn number of voice tune slots provided through one switching unit, and it is not possible to expand voice channels to exceed the!irnited m=nun number In addition, in the related art key telephone system, a request for capacity expansion of the system cannot be satisfied.

t4] The above references are incorporated bar reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical baclcround.

SUMMARY OF THE MENTION

[5] An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereloafrer.

[63 Another object of the present invention is lo provide a highway cpansion apparatus for a key telephone system and an operation method thereof that expands a capacity of a system by connecting an expansion system to the key telephone system.

[7] Another object of the, present invention to provide a highway expansion apparatus for a key telephone system and an operaiior method thereof that satisfies a request for a system: expansion using the lacy telephone system t8] In order to achieve at least the above objects, in a whole or in part, a highway expansion apparatus for a key telephone system in accordance with the present invention includes a master system including a main process board (MPB), an expansion system including a system link module unit CHIC), and connection unit for connecting the IvLPB with the system LOU.

[9] To farther achieve the above objects in a whole or part, an expansion apparatus for a key telephone system m accordance win the present invention mdudes an edge connector Hat connects to a main process board (I!IPB)

slot of a master system' a control unit that controls operations of the lcey telephone system, a switching unit having a plurality of switches to switch a pulse code modulation (?CM) voice Canal, plural tone generators each coupled to a corresponding one of the switches, respectively, to provide tones; and a system connector that connects to a system link module unit (LA4U) of an expansion system.

[1 O] To further achieve the above objects in a whole or in park an operation method of a highway expansion apparatus for a key telephone system in accordance with:he present invention includes deteriing a transrrnssion switch by using an output port nur.nber of a highway, detemng a reception switch by using an input port number of the highway, and transrutung We highway through a route of a selected reception and transmission switches.

t11] To furler achieve the armoire objects in a whole or in part, a method of operating a key telephone system in accordance with the present invention includes processing input signals by a master system reception switch and an expansion system reception switch, respectively, fistswitching an output signal of the master system reception switch and an output signal of Me Cxpanslon system reception switch and selectively transmuting the signals to each of a master system transmission switch and an expansion system transmission s=rch; and second-switching output signals of the master system transmission switch and the expansion system transmission switch.

[12] To further achieve the above objects in a whole or in part, in an expansion apparatus for a key telephone system having a master unit and a slave unit, a method in accordance with the present: invention includes judging a highway is

ouuttcd through a transmission switch of a master unit when an output port of the highway is one of a first prescribed range of values, judging a highway is outputted through a transmission switch of a slave unit when an output port of the highway is one of a second prescribed range of values greater Man the first prescribed range, determining a reception switch according to an input port slumber and a transmission Switch of the highway, and transmitting the highway through a connection route between a corresponding recepcon switch and a corresponding transmission switch.

[13] Add:ironal advantages, objects, and features of the invention will be set forth in part in We description which follows and in part will lonesome apparent to

those having ordinary slim in the art upon examination of Me following or may be learned Mom practice of the invention. The objects and advantages of the invention may be realized and attained as paricularlr pointed out in the appended claims.

BRIEF DESCRIPTION OF TTIE DRAWINGS

[ 14] We invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein.

[15] Figure 1 is a block diagram illusttatug a related art key telephone system; [16] Figure 2 is a block diagram illusadng a related art main process board; [17] Figure 3 illustrates a frame of a pulse code modulation highway;

[18] Fig - e 4 is a blocls diagram illustrating a preferred embodiment of an expansion apparatus for a leek telephone system in accordance with the present . nvennon; t19] Figure 5 is a block diagram illustrating a construction of an exemplary main process board of the key telephone system in accordance with the present invention; [20] Figure 6 is a block diagram illustrating an exemplary connectors between the MPB of a master system and a system linl; module unit (LMU) of an expansion system in accordance with the present invention; [21] Figure 7 is a block diagram illustrating a first preferred emboclimen: of a switching unit in accordance with the present inNrennon; t22] Figure 8 is a block diagram illustrating a second preferred embodiment of a switching urut in accordance with the present invention, and [23] Figures 9A and 9B are flow charts illustrating a prcierred embodiment of a method of operating an expansion apparams for a key telephone system in accordance with the present invention.

DETAIT FD DESCRIPTION OF PREFERRED EMBODIMENTS

[24] Figure 1 is a diagram that illustrates a main device of a related art key telephone system. As shown in Figure 1, the Knin device includes a hrst key service unit 100 as a basic key service unit MU), a second key service unit 110 and a third lacy service uriit 120 as expansion key service units.

t25] The first key service mat 100 as Me basic key service unit includes a power supply unit (PSIJ) 101 fox supplying srstcn power plural peripheral board (PPBs) 102, and a main process board (MPB) 103 for generally controlling functions of the key telephone system. A lid module unit MU) 104 is for interfacing with the second key service unit 110.

[26] Me second and third key service units 110, 120 being the expansion key service units, respectively, include a PSU, a PPB and a LMU. Ill Me second and *>ird key senricc units 110, 120, a portion corresponcling to the MPB 103 of Me fist key service urrit 100 is blank. The first key service trait 100 and the second key service unit 110, the second lcey service unit 110 and Me third key service urut 120 are conoccted with each over through each respective LMU for signal exchange.

[27] P - e 2 is a block diagram illustrating an ircernal construction of the related art IdPE3 As shown in Figure 2, the MPB 103 includes an edge connector 201 for connecting the MPB 103 to a MPB slot of:he first key service unit 100, a canal processing unit (CPL1) 202 for controlling general operation of the system and a reset unit 203 for rescuing a CPU 202 and the system. A CAN interface unit 204 is for supporting connection with an Internet network, and a regulator 205 is for supplying power to the MPB 103. memory unit 206 is for storing various data and programs necessary to the system. An internal I,AO 207 is a general input/ourpur port, and a dual universal asynchronous recever/transmitter (DUAR'l: 210 is for controlling inrerfaccs with a serial cornmusucarion equipment such as a modem 208 or a RS-

232C 209. An interface unit 21 I is for providing a pulse code modulation (PCM)

voice signal co the MOB 103, a switching urns 212 is for switching a PCM voice signal and a tone read only memory (tone ROM) 213 is for providing venous tones. A phase-locked loop (PLL) 214 is for providing a clock by synchronizing a phase of a ume division multiple access (IRMA) PCM voice signal The MOP 103 further includes an I/O 215 and a penpheral unit I/O 217 for providing input/oucput of plural peripheral units.

[28] Me memory unit 206 includes a prograrrunable memory unit (PMU) and a static random access memory (SHAM, etc. In adclinon, the DUART 210 processes asynchronous serial comlnunicanon by being connected to the modem 208 and the RS232C 209.

[29] The operation of the lcey telephone system shown in Fume 1 will now be described. In the power on state of the second and third key service units 110, 120, when the PSU 101 of the ask key sconce mat 100 is on, the 2PU 202 detects a connected peripheral unit and allocates a tone slot for PCM voice signal to each PPB 109. The tone slot fox We voice signal determines a capacity of Me system and has a highvay stmcture.

30] Figure 3 is a diagram that illustrates a Eame of a PCM highway. As shown In Figure 3, one fi:arne has eight sub frames, and one sub Fame is divided into eight channels. The sub flame has a high-level data Ink control (HDLC) channel of 512Kbps, a D channel for transmitting a data signal and six voice channels of 641ps each. Accordingly, one frame has 48 voice channels of 64Kbps each. The 641(bps voice data expenenccs 8Ksampling and is sent along the highway.

[31] Accordingly, due switching unit 212 can process 384 voice channels, which is deterrruned by the number of highways (e.g., 8) multiplied by the rubber of voice channels constructing one hlghw:ry (e.g., 48). In the main device of We related art key telephone system shown in Figure 1, three highways are respectively allocated to the first key service unit 100 and the second key service unit 110, and two highways ate allocated to the third key service unit 120. Accordingly, a maxirnn 384 ports can be supported. However, the system does not allow expansion.

[32] Figurc 4 is a block diagram illustrating a preferred embodiment of a expansion apparatus for a lacy telephone system in accordance with the present invention. The expansion apparatus can provide for highway expansion in a key telephone system. As shorn in Figure 4, the key telephone system can be divided into a master system and an expansion system S. The masse' system M can include a first key scnrice unit 310' a second lazy service unit 320 and a bird key service unit 330. The expansion system S can include a fourth key service unit 360, a fifth key service unit 370 and a sixth key service unit 380.

[33] The first key service r 310 of the master system M preferably includes a power supply Emit (PSI. 311 for supplying system power; plural peripheral boards (PPBs) 312; a main process board (MPB) 313 for controlling and monitoring functions of the key celephonc system and a link module unit (LMU) 314 for interfacing with the second key service unit 320 The second and third key service touts 320, 330 can have the surge construction as the key telephone system of Figure 1.

[34] The fourth key service unit 360 of the expansion system S can include a PSU 361 for supplying power to the expansion system S. plural PPBs 362, a system LMU 363 preferably for setting connection between the NIPB 313 of the master system M and the expansion system S and a LMU 364 for intctfacing with other key service wits of the compassion system S. The fifth and sloth key service units 370, 380 can have the same construction as the second and third key service units 320, 330.

t35] The master system M and the expansion system S have different constructions. The MPB 313 can be installed in the master system M, the system LMU 363 can be installed in a main process board slot of the expansion system S instead of a MPB. The MPB 313 of the master system M and the system LMU 363 of the expansion system S can be coupled to each other through a cable' and Me MPB 313 pteferably controls the operation of the expansion system S through the system LMU 3G3.

[36] Figure 5 is a block diagram illustrating an exemplary construction of the MPB (main process board) of the key telephone system of Figure 4. As shown in Figure 5, Me MPB 313 preferably includes an edge connector 401 for coupling the MPB 313 to a MPB slot of the first key service urut 310, a CPU 402 for controlling general opetaon of the system, a reset unit 403 for resetting the CPU 402 and the system, and a INN interface unit 404 for supporting connection tenth an Internet network regulator 405 can supply power to the MPS 313, and a memory unit 406 can store bayous data and programs necessary to Me system. An internal I/O 407

can provide a general input/output port, and a DUART 410 can control an Interface with a serial communication. equipment such as a modem 408 or a RS-232C 409.

[37] An interface unit 411 preferably provides a PCM voice signal to the MPB 313, a switching unit 412 can Include switches to perform switching of a PCM voice signal and a tone ROM 413 can provide various tones. A PLL 414 can provide a clock in order to synchronize a phase of a TDMA (tune division multiple access) PCM voice signal. The MPB 313 can also include an I/O 4157 an I/O voice channel 416, plural peripheral u:iit I/Os 417 for inpur/output for plural peripheral units and a system connector 418 for setting a connection between the tv1PB 313 with the system LMU 3G3 of the expansion system S preferably through a cable. Since the system connector 418 of the MPB 313 and the system LMU 363 of the expansion system S are coupled together through a cable, the MPB 313 can control Me expansion system S. [38] The memory unit 406 can Include a PMU (programmable memory unit) and a SRAM (static random access memory), etc. The interface unit 411 is prcEerably a digital backplane interface device, and it can be constructed as plural interface devices.

[39] The switching unit 412 preferably includes plural switches. The switching unit prcDcrably Includes four switches or eight switches. In addition, the switching unit 412 can be divided into a master unit for generating a highway signal to be transttcd to the master system M and a slave unit for generating a highway signal to be transmitted to the expansion system S. However, the present invention is

not intended to be so limited. In case of eight switches, the switches can be divided into four master switches and four slave switches. The tone ROM 413 preferably corresponds to each switch and provides various tones to a pertinent switch.

Accordingly, the number of switches and the number of tone ROMs can be the same. In more detail, where there are four switches in the switching unit 412, the number of tone ROMs are four, when Were are eight switches in the switching unit 412, the number of tone ROMs are eight.

[40] Figure 6 is a block diagram illustrating an exemplary connection between the MPB of the master system and the system LOU of Me expansion system in accordance with the present nvenaon. As shown in. Figure G. an interface between Me master system M and doe expansion system S will now be described.

[41] The system LOU 363 of the expansion system S can include a system connector 501, a decodes 502, a buffer 503, a M1JX/lDeMUX 504, an edge connector 505 and an interface unit (OBID) SOG. Preferably, the same signal with a signal of the MPB 313 of Me master system M is provided to the system LOU 3G3 of the expansion system S. [42] The system connector 501 can set a link between the MU 313 of the master system M and the system LMU 363 of the expansion system S. The decoder 502 can generate a chip selection signal for accessing a non-intedigent peripEt:ral (NIPP) board by assembling an address bus transmitted from Me master system M and designating a specific address.

[43] The buffet 503 is for pretreating distortion of a signal transmitted from the master system M. The buffer 503 can prevent signal distortion of an address bus, a data bus and a control bus transmitted from the MPB 313 of the master system M. t44] The MUX/DeMUX 504 is for accessing an intelligent peripheral (IPP) bon rd. The MUX/DeMUX 504 can control three key seance units constructing the expansion system S by using a 512Kbps hgh-leve] data link control (HDLC) signal transmitted from the CPU 402 of the MPB 313 [45] For example, when a high-level data link control signal transmitted Prom the CPtJ is '01', the MUX/DeM 504 can control the fifth key service unit 37O of the expansion system S. When a high-lercl data link control signal transmitted from the CPlJ is '10', the MUX;/)eMl:X 504 can control Me sixth key service unit 380 of Me expansion system S. [46] The edge connector 505 of Me expansion system S is coupled to a mother board of the fourth key service unit 360, and the interface unit 506 provides a high-level data lisle control signal of the expansion system S and a basic voice signal [47] Interface operations between Tic master system M and Me expansion system S will now be described. A transfer signal ouq?utred from the switch of Me master sys tern M is transrrutted to Me expansion system S through Me buffer. The system LMU 363 of file expansion system S can receive an address bus, a dare bus and a control bus ransrnitted from He MPB 313 of the master system M. The buff S03 can reduce or prevent distortion of the received signal.

[48] The decoder 502 assembles He receivers address bus and data bus in order to access a pertinent peripheral unit among coupled peripheral units by judging the assembled result and can transrrnt the transfer signs to the pertinent peripheral unit. The MUX/I)eMUX 504 can control at least one of the three key service units of the expansion system S lay using the HDLC signal transmitted from the MPB 313 of the master system M. [49] Figure 7 is a block diagram illustrating a first preferred embodiment of a switching unit and peripheral units thereof in accordance with the present invention. As shown in Figure 7 the switching unit consists of four switches However, the present invcution is nor intended to be so limited.

[50] The switching uruc 412 preferably includes a master system reception switch M11 for switching highway of the master system M, an expansion system reception switch S11 for switching highway of the expansion system S. a rrmster system transmission switch M12 for transmitting the highway outputted from the master syscern reception switch M11 to the master system M; and an expansion system transIrussion switch S12 for transrnittng the highway outputted from the expansion system reception switch S11 to the expansion system S. The switching unit 412 can also indude the PLL 414 for prodding a clock to synchroruze each highway, and tone RQMs rf11T14 respectively coupled to the switches M11, S11' M12, S12 proridc various tones.

[51] Operations of the switching unit 412 Mat includes He four switches will be described. The master system reception switch M11 can generates a frame

signal on the basis of 32.768M!Iz transmitted from the PLL 414 and transmits it to :he expansion system reception switch S11, the master system Transmission switch M12 and the expansion system transrr.ussion switch S12. By the frame signal' highways generated at the master system reception switch M11, the expansion system reception switch S11, the master system transmission switch M12 and the expansion system transrrnssaon switch S12 can be synchronized.

[52] The Blaster system reception switch M11 preferably processes a reception signal received from the master system At, and the expansion system reception switch S11 processes a reception signal received Mom the expansion system S. Each reception signal transmitcd to the master system reception switch M11 and the expansion system reception switch S11 can have eight highways.

[53] Among the eight highways processed-outputeed Prom the master system reception switch M11' 'our highways are preferably transmitted to Me master system transnssion switch N[12, and the remairung four highways are transrutted to the expansion system transrrussion switch S12. In adclitlon, among the eight highways processed-outputted Mom the expansion system reception switch S11, four highways cads be trarlsrrureed to the master system transtnission switch M12, and the remaining four highways can be transmitted to the expansion system transmission switch S12.

t54] The master system transmission switch M12 can output eight highways by processing the four highways from the master system reception switch M11 and the four highways from Me expansion system reception switch S11. In addition, the expansion system Admission switch S19 can output eight highways by processing

the four highways from the master system receptors swlch M11 and the four highways from the expansion system reception switch S11. However, the present invention is nor intended to be so limited as other combinations of highways can be used. [55] Preferably four highways of the eight highways Dom the master system transmission switch M12 and the four highways of the eight highways from the expansion system transmission switch S12 are nplell.ented as eight highways and are transmitted co the master system M. The remaining highways from the master system transmission switch M12 and the red four highways from the expansion system transmission switch 512 are unplcmented as eight highways and are crans:Tutted to the expansion system S. [56] In the switching unit 412 shown In Figure 7 having four switches, because four master systerr highways and four expansion system highways are inputted to the master system t:ansrsussion switch M12 and Me expansion system transgression switch S12, respectively' vrhen mote Man 192 ports are coupled between a reception Switch and a transmission switch, excessive load may occur.

[57] [Figure 8 is a block diagram illustrating a construction of a second preferred embodiment of a switching unit and peripheral units in accordance with the present invention As shown in Figure 8, the smirching unit 412 can have eight switches. In addinon, the switching unit 412 can be divided into a master unit for generating a highway signal to be t:anstrutted to the master system M and a slave unit for generating a highway signal to be transmitted to the expansion system S.

[58] The master unit can include a rnasrex system reception switch N1 for receiving highways of the master system M and an expansion system reception switch M22 for receiving highways of the expansion system S. master system transmission switch M23 and a master system transmission switch M24 can generate highways to be transmitted to the master system M by sclcctivcly exchanging the highways from the first master system reception switch M21 and the highways from the first expansion system reception switch ivL22 with each other.

[59J lithe slave unit can include a second master system reception switch S21 for receiving highways of the master system N[ and a second expansion system reception switch S22 for receiving highways of the expansion system S. First and second expansion system transmission switches S23, S24 can generate highways to be transmitted to the expansion system S by selectively exchanging the highways from the second master system reception switch S21 and the highways from the second expansion system reception switch S22 with each other.

[60] In adclition, the switching unit 412 or the slave unit can include the PLL 414 for providing a cloclc to each switch in order to synchronize highways generated In the eight switches, and tone ROMs T21T28 can be respectively coupled to Me switches and can provide various cones.

[61] Operations of Me switching unit 412 shown in Figure 8 will now be described. The first master system reception switch M21 can receive a 32. 768tIz ffarne signal Mom e PLL 414 and output a frame signal (ea. a 8. 192MHz frame signal). Ilae output Signal of the PLL 414 and the output signal of the first master

system reception switch M91 axe preferably trnsIIiitted to the second master system reception switch S21, the host and second master system transmission switches M23, M24, the first and second expansion system reception switches M22, S22 and the first and second expansion system transmission switches S23, S24. By Me frame signal, highways generated at the eight switches can be synchronized.

[62] Lyle firs: roaster system reception switch M21 and the second master system reception switch S21 preferably process reception signals from the master system M, and the first expansion system reception switch M22 and the second expansion system reception switch S22 preferably process reception signals rorA the expansion system S. Each,receprion sidereal can have eight highways [63] Output signals of the East master system reception switch M21 and the first expansion system reception switch M22 can be transmitted to the fast master system transmisscn switch M23 and the second master system transmission smirch M24. Among eight highways outputted from the host master system reception switch M21, four arc preferably tlansrDitted to the first master system transmission switch M23, and the remaining four are preferably transmitted to the second master system transmission switch M24. However, the present indication is not intended to be so bruited as various asymmetric combinations could be transmitted as long as all highways preferably are conrollaWy passed to the transmission switches. Among eight highways outputted from Me first expansion system reception switch M29, four are preferably transmitted to the firs: master system:ansmission switch M23, and the four are transmitted to ache second master system transmission switch M24.

[64] Output signals of the second master system reception switch S21 and the second expansion system reception switch S22 are preferably transmitted to the s: expansion system transmission switch S23 and the second expansion system transrriussion switch S24. Among eight highways outputted from the second master system reception switch S21, four are preferably transmitted to Me first cpansion system transmission switch S23, and the remaining four preferably ransmittcd to the second expansion system transmission switch S24. In addition, among eight highways outputted from the second expansion system reception switch S22, four can be transmitted to the Best expansion system transmission switch S23, and the temanir four can be transmitted to the second expansion system:ansmission switch S24 [65] 'line first master system transmission switch M23 and the second master system transmissiol1 switch M24 can process four highways frown the Erst master system reception switch M21 and four highways from the first expansion system reception switch M22 and output four highways, respectively. The highways outputted Tom the first master system transmission switch M23 and the second master system transmission switch M24 are preferably added to each other, and accordingly eight highways can be transmitted output to the master system M. [66] The first expansion system transmission switch S23 and the secondexpansion system transmission switch S24 can process four highways from the second master system tecepQon switch S21 and four highways from the second expansion system reception switch S22 and output four highways, respectively. The (., ';

highways outputted from the first expansion system transrrussion switch S23 and Me second expansion system transmission switch S24 are preferably added to each other, and accordingly eight highways can be output to the expansion system.

t67] Signals outputted from the first and second master systerr transmission switches M23, M24 can 1'e.rrans=.:ted to a backplane cuff the master system hi, and signals outputted from the first and second expansion system transmission switches S23, S24 can be trarsnutted to a backplane of ube expansion system S. [68] The highways are divided into transmission highways and rccepton highways, arid the switching unit 412 preferably supports nisle transmission highways and cigl1t reception lghways. Since a tone lghway is preferably included in the transmission highways, Tic number of transmission highways is greater than Me number of reception highways by 1.

[69] In the key telephone system in accordance with preferred embodiments of the present invention, it is possible to provide 384 ports supporting the expansion system by connecting Me expansion system S to the master system of Figure 1 and using the eight ssvitces. Accordingly, a total voice channel capacity is expanded from 384 ports to 768 (384x2=768) ports.

[70] A method of operating the key telephone system in accordance win a preferred embodiment of tile present invention will be described Aim reference to Figures 9A-9P. As shown in Figures 9A-9B, tile operation method can be implemented and will be described using Me second preferred embodimcut of the

expansion apparatus for the key telephone system of Figllrc 8. However, Me desert invention is not intended to be so lirndted.

t7 1] When a highway is inputted to Me system' a prescribed internal algorithm designates a pertinent transmission switch by checking an output port number at which the highway is transmitted and determines a preferred or an ideal highway transmission route by checking an input port at which the highway is inputted. Thus, the prescribed algorithm can deter7inc venous combinations between the input port and the output port of Me highway.

[723 Each transmission switch supports 192 (4x48=192) ports because the four transrrussion switches output four highways, respectively. In the smtching unit 412 of Figure 8 having eight switches, the first master system transmission switch M23 can support a port number O 191, Me second master system transmission switch M24 can support a port number 192 383, the Best expansion system ansrrussion switch S23 support a port number 384 574, and the second expansion system transmission switch S24 can support a port numbet 576 767.

[733 The system preferably checks an output port nunbet of a highway through the prescribed internal algorithm as shown at ST1 When the value (c.g.

Ou:put port number) is less than 191, it is judged Me highway is preferably outputted to the master system through Me first master system transmission switch M23 as shown at steps ST2 and ST3. When the value (e g output port rurnber) us not less than 191 and less than 383, it Is judged the highway is preferably outputted tO the master system M through the second master system transmission switch M24 as ...

shown at steps ST4 and ST; When the value (e g output pore number) is not less than 383 alla less than 575, it is judged the highway is preferably outputted to the expansion system S through the first expansion system transmission switch S23 as shown a: steps ST6 and ST7. When the value (e. g., output port number) is greater than 57G, it is judged that highway is preferably outputted to the expansion system S through the second expansion system transmission switch S24 as shown at seeps ST8.

[74] After determining the output port, an input port number of the highway can be checked as shown. at steps ST9 and ST10. The input port numDcr can be determined according to a second prescribed algothrn.

75] When an input pow number of the highway having the first M23 or second master system transmission switch M24 as the output port is less than 333, it can be judged the highway is inputted through the first master system reception switch (e.g., M21) as shown at steps ST11 and ST12. When preferred or a input port number of the highway having Me first M23 or second master system transmission switch M24 as the output port is not less than 383, it can be judged the highway is inputted through the first expansion system reception switch (e.g., M22) as shown at step ST13. When an input port number of the highway, which has the first S23 or second expansion system transmission spinach S24 as the output port, is less than 383, it can be judged the highway is inputted through the second master system reception switch (e.g., S21) as shown at steps ST14 and ST15. When an input port number of the highway having the first S23 or second expansion system transmission switch S24 as the output port is nor less than 383, it can be judged the highway is inputted An.

through the second expansion system reception switch (e g., S22) as shown at step ST16. [76] When a preferred or ideal transmission route of the highway is set, the signal is inputted through a pertinent switch among the first and second master system reception switcl1cs, the first and second expansion system recepnon switches, and the signal is outputted to (he master system M or the expansion system S through the detemiined transmission switch as shown at ST17.

[77] For example, if there is a signal having an input port value as 187 and an output port as 519, the signal is inputted Trough the second master systems receptors switch and is outputted through the first expansion system transmission switch. If these is a signal having an input port value as 452 and an output pots as 87, the signal is inputted through the first expansion system reception switch and is outputted through the first master system transmission switch [78] As described above, using preferred embodiments of a highway expansion apparatus for the key telephone system and operation methods thereof in accordance with the present invention, it is possible to connect an expansion system to a master system. Further, a voice channel capacity of a key telephone system can be expanded, for example, from 384 voice channels to 768 voice channels. In addition, in preferred embodiments of a highway expansion apparatus for a Icey telephone system and methods of operating the same us accordance with the present invention, by expanding a capacity of a system by using an expansion system having the same structure with the existing lacy telephone system, it is possible to expand a

capacity of the existing system. Further, by setting a route corresponding to an input port and an output port of a highway can be set using a plurality of switches and by using eight switches, it is possible to prevent excessive load in accordance with the prefctrcd cmbodimcuts.

/'9] The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can he readily applied to other types of apparatuses. Tic description of the present

invention is intended to be illustrative, and not to limit the scope of the claims. Many altctnativcs, modifications, and vocations will be apparent to those skilled In the art.

In the claims, means-plus-functron clauses ate intended to cover the structures described hegira as performing the recited fimction and not only sttuctural equivalents but also equivalent structures.

Claims (6)

CLAIMS:

1. An operation method of a highway expansion apparatus for a key telephone . system, compnslng: determining a transmission switch by using an output port number of a highway; determining a reception switch by using an input port number of the highway; and transmitting the highway through a route of a selected reception and transmission switches.

2. The method of claim 1, wherein the route comprising a selected one among a plurality of reception switches and a selected one among a plurahty of transition switches according to prescribed criteria.

3. The method of claim 1, wherein the transmission switch comprises: a master system transmission switch for outputting an output signal of the reception switch to the master system; and an expansion system transmission switch for outputting an output signal of the reception switch to the expansion system.

4. The method of claim 3, wherein the reception switch comprises: a master system reception switch for receiving a highway of the master system; and an expansion system reception switch for receiving a highway of the expansion system.

5. In an expansion apparatus for a key telephone system having a master unit and a slave unit, a method, comprising: judging a highway is outputted through a transmission switch of a master unit when an output port of the highway is one of a first prescribed range of values; judging a highway is outputted through a transmission switch of a slave unit when an output port of the highway is one of a second prescribed range of values greater than the first prescribed range; determining a reception switch according to an input port number and a transmission switch of the highway; and transmitting the highway through a connection route between a corresponding reception switch and a corresponding transmission switch.

6. The method of claim 5, wherein the determining a reception switch comprises: determining the reception switch of a highway as first master system reception switch when the highway has an input port number within the first prescribed range and has an output switch as the master unit transmission switch; determining a reception switch of a highway as first expansion system reception switch when the highway has an input port number within the second prescribed range and has an output switch as the master unit transmission switch; determining a reception switch of a highway as a second master system reception switch when the highway has an input port number within the first prescribed range and has an output switch as a slave unit transmission switch; and determining a reception switch of a highway as a second expansion system reception switch when the highway has an input port number within the second prescribed range and has an output switch as the slave unit transmission switch.