CA2028791C - Telephone system - Google Patents
Telephone systemInfo
- Publication number
- CA2028791C CA2028791C CA002028791A CA2028791A CA2028791C CA 2028791 C CA2028791 C CA 2028791C CA 002028791 A CA002028791 A CA 002028791A CA 2028791 A CA2028791 A CA 2028791A CA 2028791 C CA2028791 C CA 2028791C
- Authority
- CA
- Canada
- Prior art keywords
- speech
- digital
- communication network
- gain
- telephone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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- 230000006870 function Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 10
- 230000001276 controlling effect Effects 0.000 description 6
- 101150087426 Gnal gene Proteins 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- BSFODEXXVBBYOC-UHFFFAOYSA-N 8-[4-(dimethylamino)butan-2-ylamino]quinolin-6-ol Chemical compound C1=CN=C2C(NC(CCN(C)C)C)=CC(O)=CC2=C1 BSFODEXXVBBYOC-UHFFFAOYSA-N 0.000 description 1
- 101100518689 Bacillus subtilis (strain 168) padR gene Proteins 0.000 description 1
- 101100021570 Caenorhabditis elegans lon-3 gene Proteins 0.000 description 1
- 101100496106 Mus musculus Clec2f gene Proteins 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 208000003251 Pruritus Diseases 0.000 description 1
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- 230000001105 regulatory effect Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/253—Telephone sets using digital voice transmission
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/40—Applications of speech amplifiers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/002—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems
- H04M9/008—Multiplex systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/005—Interface circuits for subscriber lines
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M7/00—Arrangements for interconnection between switching centres
- H04M7/0096—Trunk circuits
Abstract
In a key telephone system connectable to both ISDN and PSTN, for the purpose of compensation of a difference in speech signal level between ISDN and PSTN, digital pads are incorporated in an ISDN interface unit mounted on a key service unit of this system. In the digital pads, original PCM-code speech signals received/transmitted from/to the ISDN line are converted into PCM-code speech signal with a compensated speech signal level obtained by adding a selected gain to the original speech signal level. Since the difference in the speech signal level between ISDN and PSTN differs according to the conditions, an appropriate gain is selected from a plurality of previously prepared gains.
That is, the relationship between telephone numbers and information signals indicative of the selected gain is registered in the key service unit. Therefore, when conversation is made to a subscriber whose telephone number has been registered through the ISDN, a gain registered in correspondence to the subscriber's telephone number can be selected automatically.
That is, the relationship between telephone numbers and information signals indicative of the selected gain is registered in the key service unit. Therefore, when conversation is made to a subscriber whose telephone number has been registered through the ISDN, a gain registered in correspondence to the subscriber's telephone number can be selected automatically.
Description
~ ~ 202879 1 TELEPHONE SYSTEM
BACKGROUND OF THE INVENTION
The present invention relates to a telephone system and more specifically to a transmission level regulating method for a telephone system connectable to both analog and digital communication networks.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram showing the general system configuration of a key telephone system connectable to both the two networks of ISDN and PSTN;
Figure 2 is a block diagram showing an ISDN interface unit used for an embodiment of the key telephone system according to the present invention;
Figure 3 is a diagram for assistance in explaining the relationship between input and output signals of a transmit/receive digital pad provided in the interface unit shown in Figure 1;
Figures 4(A) and 4(B) are diagrams for assistance in explaining a plurality of subpads provided in the transmit and receive digital pads, respectively;
Figure 5 is a block diagram showing a microprocessor provided in the interface unit shown in Figure 2;
Figure 6 is a block diagram showing a control circuit provided within the interface unit shown in Figure 2;
Figure 7 is a block diagram showing a PSTN interface unit used for the afore-mentioned embodiment;
Figure 8 is a block diagram showing a standard telephone set interface unit of the above embodiment;
~- 20287Y 1 la 20375-675 Figure 9 is a block diagram showing a central control unit of the above embodiment; and Figure 10 is a block diagram showing a microcomputer incorporated in the central control unit shown in Figure 9.
As an example of telephone system of this type, there exist key telephone system connectable to both the integrated service digital network (ISDN) and the (analog) public subscriber telephone network (PSTN). Figure 1 shows a typical system configuration of this telephone system. On a key service unit 1, there are mounted an ISDN interface unit 5 connected to an ISDN
line 3, a PSTN interface unit 9 connected to a PSTN line 7, an extension terminal interface unit 15 connected to a line 13 from an extension terminal 11, etc. These interface units are connected to a control unit 20 for controlling the entire key service unit and channel switching, via a data highway 17 serving as a time-sharing transmission line for control data and a speech highway 19 serving as a time-sharing transmission line for speech PCM (pulse code modulation) codes.
Here, there exists a loss of 4 dB on an average between a subscriber for the PSTN line 7 and a terminal office. In addition, some loss is inevitably produced in a 2-4 line switching circuit and a CODEC (coder/decoder) of an office line (PSTN) interface unit 9. Further, in general the key service unit 1 is so designed that there exists a loss of about -1 dB between the office line (PSTN) interface unit 9 and the individual telephone set interface unit 15.
On the other hand, no loss exists between a subscriber for the ISDN line 3 and a terminal office. Further, the -lb 20375-675 conventional ISDN interface unit 5 performs only signal representation transformation between ternary codes and binary codes, speed conversion between 64 Kb ' :' 20287~ 1 and 2,04~ Mb, multiplexlng, ~eparation, etc. in general, without perfor~lng conver~ion ~ith respect to the ~peech PC~ codes.
A~ a ~esult, ~hen an extension telephone se~ 1 is connect~d to an outslde llne telephonc 3et ~uch a3 an analog telephone set 23, there arise~ the follow~ng problem: Since both the I~D~ and PSTN llne~ are connected to the key ~ervioe unit 1, although telephone conver~ation can be made throuqh any one oE the two line~, there exist6 a a; ~ference in spee~h (t~an~mi~slon) level between the two line~, be~ause the 10~5 through the P8~N line 7 ~5 di~erent ~ro~ th3~ through the ISDN line 3, a~ already expla~ned. In other worde, the ~pee~h le~el differ~ according to the used network, when conver~ation is made with the same per~on. ~he similar differ~nce in the speeoh level occurs between when the extenqion telephone ~et 11 is connected to a digital telephone ~et 21 and when the exten6ion telephone 6et 11 i~ connected to an analog telephone set 23. In addition, the d~f~erence in speech level ~hange~ being s~bjected to the influence oE in~tallatlon conditions of the line~ 3 and 7 and the key 6ervice unit 1.
A~ described above, in a telephone sy~tem conn~c~ed to both the analog and digital communication networks, 2S thQre exists a problem in that the speech ~tran~mi~ion) level differs acco~ding to the connected network and further the level d1f~erence varie~ according to the de~ice in~tallation condi~lon3, thu~ resulting in a difE~culty in malntaining an appropriate ~peech level all the time.
SU~Y OF THE INVENTION
With these problem~ in mind, thereore, lt ia th~
ob~ect of the pre~ent ~nvention to provide a telephone ~y~tem whlch can automatl~ally regulate the ~p~ech level, irrespect~ve o~ the connected networks.
To achieve the above-ment~oned ob~ect, the pre~ent invention provides a telephone ~ystem connectable to both a digital communication network and an analog communication network which comprises:
(a) terminal means provided with functions of transmitting/receiving speech signals;
(b) digital network interface means for providing an interface for communicating the speech signals in digital code form between the terminal means and the digital communication network;
(c) analog network interface means for providing an interface for communicating the speech signals in analog signal form between the terminal means and the analog communication network;
(d) speech level attenuating means for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network, and for adding the selected gain to the speech signals communicated in digital code form between the terminal means and the digital communication network; and (e) gain control means for controlling the gain selection by the speech level attenuating means.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention will be explained hereinbelow with reference to the attached drawings.
The embodiment described below is a key telephone system whose basic system configuration is the same as shown in Figure 1. In more detail with reference to Figure 1, a key service unit 1 comprises an ISDN interface unit 5 connected to an ISDN line 3, a PSTN interface unit 9 connected to a PSTN line 7, and a standard ~`
`` - 202879 1 telephone device interface unit 15 connected to an extension telephone set (e.g. a standard telephone set) 11. These interface units are connected to a central control unit 20 for controlling various calling and s-witching processing via a data highway 17 and a speech highway 19.
Figure 2 shows a configuration of the ISDN interface unit 5 of the present embodiment. In Figure 2, 2-channel speech data and 1-channel control data fed through a receive interface line 31 of the ISDN line 3 are converted from ternary signal to binary signal, and then applied to an interface LSI 37. In this LSI 37, processing related to two different layers (e.g.
separation of speech data (layer 1) from control data (layer 2)) in accordance with programs or other information for controlling the operation of the interface LSI 37, which are stored in a ROM
39 and a RAM 41. The separated speed data are inputted to a ..~
, .
- 5 202879~
multiplexlng ~nd seeial/parallel transforming seçtion 43 via a fi~6t port receive data lLne PlRXP and a second port recei~e data line P2RxD. In the multiplexing and series/parallel tran~orm~ng section 43, 2-ch~nne~ ~peech S data transmitted in serial mode at G4 Kbps a~e multiplexed into 128 Kbps, t~an~formed into p~rallel ~ode, and then fed to a b~s 45. These par~llel speech data ~a-bit PCM ~odes) are inputted to a ~O~ ~i.e.
recei~e digital pad) 4~, and ~-bit PCM codes stored at an address area corresponding to the speech data are read out of the receive digital pad ~PA~) 41 and then fed to a bus 49.
As sho~n in Plg. 3, thi~ receive digital pad 47 iB
constructed in 6uch a ~ay a~ to r~ceive ~peech data represented by 8 lo~eF ~ign~ fican~ 3ddre~ blt~ ~ to ~7, a slgnal ~o~ seleoting a gain rep~esented by t~o middle ~ignificant bl~s A~ and A9, and a signal for controlling the on-off operation oE thi~ pad repre~ented by the most ~ignificant bit lOA. Further, the gain selecting sign~l based on the b~ts A8 and A9 and the on/o~ con~rol signal based on the b~ t lOA are gi~en from a controller 51.
As shown in Fig. 4, thls pad 47 is provided with 8 subpad~ 0000 to 0700, and each subpad include~ ZS6 addre~s areaa ea~h of which can be ~elected in regponse to a ~pee~h data repre~ented by bits AO to A7. The first ~o fourth ~ubpads f~om 0000 to 030~ are selected to produce a galn of 0 dB li.e. no gain) when the logical value of the on/o~f ~ontrol signal rep~e~ented by a bit A10 ~s "0" ~off~. That i~ bit code~ the same a6 the speech data rep~esented by bits A0 to A7 are ~tored at the ~ddress area~ of the subpads, respeotively. The fifth to eighth subpads from 0400 to 0700 are selected to produce one of four different gains of -6, -3, 0, and +3 d~ according ~o the logical val~e o~ the gain selecting slgnal represented by bits AB and A9 when the loglcal value of the on/off control signal A10 i3 ~ on). That i~, 8-blt aode~ obtained by adding each ga~n to the 2028~9 speech data represented by bit~ A0 to A7 ~re stored at the address area~ in the subpads, re6pectively.
~ ith reference to ~ig. 2 again, the ~peech data to whlch a 6elected gain ~s added and read out of the receive digltal pad 47 are inputted to a con~ers~on section 53 to ~onvert the parallel data to 2 ~bp~ serial data, and then superpo6ed upon a designated time slot of an up-l~ne of the ~peech high way 19. In addition, the conve~sion sectlon 53 read~ speech data from a designated t~me ~lot of a d~n-line of the ~peech high way 19. The read spee~h data are converted into parallel data and then ~ent out to a bus ~9. The parallel spe~ch d~ta are inputted to a tran~mit digital pad 55. Thls tran6mit digl~al pad 55 i8 a ROM similar to the receive d~gital pad 47, and re~eives speech dat~ repre~ented by 8 lowe~
eignific~nt addres6 bit6 AO to A7, a gain selecting signal represented by two ~iddle ~ignlficant bl~6 A8 and A9 and an on/off control signal represented by the ~09t ~ignificant bit lOA as shown in ~ig. 3. ~urther, as shown ~n ~19. 4~ the transmit digital p~d 55 c~n select any one o~ ~ains oF O (off), -12, -g, -6 and -3 dB.
Speech data read out of the transmit digi~al pad 55 are inputted to a parallel/~erial conve~tin~ and ~epar~tlng sect~on 59 via a bu~ S7. The parallel/serlal Z5 converting and ~eparating section 59 convert~ 2-ohannèl spee~h data inputted in parallel at 128 Xbp~ speed, respectlvely into serial data, separates these data acoording t~ ~he ch~nnels, and ~ends the data to a fi~st port tran~mit data line PlTXD and a se~ond port tran~mit data line P2TXD. ~he~e ~pee~h data are ~urther ~nputted ~o the interface LSI 37, multiplexed ~ith control data, converted ~nto ternary 6ignals by a drivèr/reo~lver 35, and then ~ed ~o a trans~it inter~ace line 33 o~ the ~SDN
lin~ 3.
On the othe~ hand, oontrol data (selection signals, pro~ess identifier~, eto.) inputted to the in~er~ace LSI
37 ~la the ISDN line 3 are isolated from speech data, 7 202879~
~nputted to a communication repeating microp~oces~or 61, and then t~ansmitt~d to a central control un~t 20 via a data high~ay 17. Fu~ther, program~ and other information for controlling the operation o~ the microproce6~0r 61 are stored in a ROM 63 and a RAM 6~.
The control data given from the central control ~nit to the IS~N interface unit 5 are inputted to the m~croprocessor 61 via the data highway 17~ Some data among control data inpu~ted to the microproce~6or 61 are applled to the ~nterace ~SI 37 ~o as to be m~ltiplexed with speech data bef~re sending out to the transmit interace line 33 via the driver/~ecelver 35. Further, described later, cont~ol data given fr~m the ~entral control unit 20 in~lude data for controll~ng the receive digital pad 47 and the transmit digital pad 55. In response ~o the pad control data, the microp~ocèssor 61 output~ pad control signal~ to the controller 51. The controller 51 set~ three hi~her signlficant ~ddress blts A8, A9 and A10 applied to the re~eive and transmlt dlgital pads 47 and 55 to value~ designated by the pad control s~gnals, so that one subp~d of each of the digital pad6 ~7 and S5 ~9 selected and enabled. Further, a digital P~L (phase locked loop) circuit ~7 and a f~equençy ~ultiplie~ ~9 ~re incorporated to synchronize a clock requency of ~he speech highway 19 with that of the ISDN line 3.
Fig. S show~ a qonfiguration of the micropro~essor ~1 within the ISDN interface unit 5. ln ~e drawing, a oontrol ~i~nal receive se~tion 611 ha~ access to a spe~ific tlme 510t designated by a slot address ~ign~l on a town-highway D~OUT ~f the data highway 17 to rece~ve control data 6upplied fro~ the central control un~t 20, and separates pad control data from other çontrol da~a.
The sepa~qted pad control data are sent ~o a pad control 3S slgnal transmit sec~ion 613, from wh~ch the pad control signal~ are transmitted to the c~ntroller Sl. The othe~
202879~
control data are tran6~itted to the interfa~e LSI 37 via an in~er~a~e ~SI control signal tran~mlt ~ection ~15.
An interface ~SI control signal receive section 617 recelves oontrol data ~rom the interface LSI 37, and 5 ~ends the received control data to a oon~rol ~ignal transmit se~tion 619. The ~ontrol slgnal transmit section 619 ha4 acceEs to a speci~ic t~me ~lot de6ignated by a slot addre6æ ignal on an up-highway DHIN oE ~he data highway 1~ to transmit control data from the 10 interfaoe ~SI 37 to th~s ~ime slo~. The tran~mltted control data are sent to the central control unit 20.
Fig, 6 shows a configuration of a pad c~ntrol related sectlon of the ~ontroller 51 within the ISD~
interface unit S. In the drawing, the pad control 15 signal6 from the microprooes~or 61 are inputted to a ~ 2 swltching section 511. This swltc~n~ sectlon Sll di6crimlnates whether the pad control signal is related to pad control of ~1 channel or B2 channel, and transmit~
pad control signals related to the Bl channel ~o a 20 control ~lgnal receive sec~lon 513a and those related to ~he B2 channel to another control slgnal recelve sect~on 513b, re~pe~tively.
The control signal reoeive sec~on 513a for receiving the Bl-channel related pad control signal 25 obtains pad on/of~-related information from the conteol signals, and further recogni~es a selected subpad number when "on" is ob~ained. The pad on/o~f lnformation ls fed to an A10 controller 515a. The A10 controller 515a forms a Bl cha~nel rel~ted on~off con~rol sign~l and outp~t6 30 the formed ~ontrol signal to ~ne input t~rminal A of a ~electo~ 519. When ~1 channel related pad6 are turn~d on, further a selected subpad number is inp~tted to an encoder 51~a. The en~oder 517a form6 a ~-blt data repre6entative o an input~ed subpad number, and outputs thl3 data to two input terminals Al and A2 of a ~elec~or 521, g 202879~
With respect to the ~2 channel, the same pr~cessing as described above are implemented by ~ contro~ ~gnal recei~e section 513b, an A10 controlle~ 515b and ~n encoder 517b. As a result, B2-channel related on/off control signal is applied ~o the other input ter~inal B
o~ the selector 519. When B2 channel related padR a~e turned on, further a 2-bit data rep~esentative of a ~elected subpad number are appl~ed to two input termlnals 81 and ~ of the selecto~ 521.
The sélector Sl9 output6 an on/off control 6ignal seleoted from one of t~o input terminal~ ~ and B. ~he outputted on/off control sign~l i6 applied to the ~o~t significant address bit Al~ of both the recelve and transmit digital pads 41 and 55. The selector 521 15 outputs a 6ubpad number data ~elected from one pai~ of the input terminals Al, ~2 and B1 and B2. The outputted subpad numbe~ data are added to the succeedlng address b~ts A9 and A8.
A timing signal generating sec~ion 523 divides a 20 frame synchronizlng ~ignal into 1/2 to fo~m a ~ 2 sw~tching signal as shown in ~ig. ~. The fo~med switching signal is applied to the selector termlnal~ SE~
of the two selector3 519 and ~21, respe¢tively. A~ a re~ult, an on/of f con~rol signal and a subpad nurnber data ~5 related to the al channel are ~ele~ted during a fi~t half of each frame, and an on/off control signal and ~
subpad number data rela~ed to ~he B2 channel are selected during a second half o~ each frame. These select~ed signal~ an~ data are applled to addres~ bit~ A10, A9 and 3~ ~8 of the receive and ~ansm~t digital pads 47 and 55, in order to determine each gain rel~ted to the ~1 or ~2 channel~
~ ig. 7 show~ a configuration of the PSTN interface unit 9. An interface circult 91 includ~ng a call signal 3S detec~or g3, a polarity 1nversion detector 95 ~nd a dc ~oop ci~cuit 97 15 connected to the P~TN line 7, ~n ordee to detect ~ call ~ignal from the line 7, the polar~ty -2028~
inverslon of the line 7 and the close/open of a dc loop, and further to 6end dial pulses to the line 7. A codec 99 convert~ spee~h signals fro~ analog to digital or vice versa, which i~ ~onnectet in A~ ~anner to the line 7 wh~n 5 a dc loop is closed by the DC loop circuit 97.
A time 510t a66igner 101 dec~des a timing at whlch the codec 9~ receives or t~ansmits speech d~ta through the ~peech highway 19 on the basi6 of a time 910~ addre~s previou~ly det~rmlned for the codec 9~, a frame 10 synchronlzing s~gnal fro~ the speech highway 19 and a clock, and applies a deter~ined timing signal to the codec 99. The codec ~9 recelves or trans~5ts speeeh d~ta through the speech highway lg within a time period a33igned by the time slot ass~gne~ 101.
A control data co~munication ~i~rocomputer 103 monitor~ dete~tion 6ignals f~om ~he call ~i~nal dete~to~
93 and the pola~ity inversion detector 9S, controls the DC loop circult 97, and receive~ and t~an~mlts various control data related to the call signal detection ~ith 20 respect to the cent~al con~rol unit Z0, the pola~ity invers~on detection, dc loop opening/closing, and the dial pul~e transmi~s~on, etc. through the data high~ay 17.
Fig, B ~how~ a configuration of a standard telephone 25 ~et interfa~e unit 15. A call signal tran~mltter 105 t~ansmlts a call signal (e.g. 16 Hz ac 6ignal) ~upplied from a call signal generato~ 107 to a fitandard telephone ~et 11. A dc voltage supply clrc~it 10~ supplies a pre~r~bed dc voltage to the ~tandard telephone 5et 11 to 30 in~ert the polarlty the~eof, and detect~ the do-loop opening/clo~ing by the standard telephone set 11. A dial detector 111 detects a dial p~lse of the telephone ~et 11 .
A codec 113 converts speech signals from analog ~o 35 dig~tal or vice ~rsa and receive~ and transm~ts spee~h data through ~he speech highway 19 within a time pe~od asslgned by the time slot assigner 115.
-20Z8~91 A control ~ata communication ~icroco~puter 117 control~ the call si~nal transmit/interrupt ~on/off), ~onitors the dc loop opening/closlng, control6 the polarlty invers~on, mon~tors the dial pulse detection 5 re~ult, and ~om~unicate~ control data ~ith the central control unit 20 throu~h the d~ta hlghway 17.
Flg. 9 show~ a ~onfigura~ion oÇ the central con~rol ~nlt 20 of this embodiment. ~he central control unit ~0 lncludes a control microcompu~er 71 connected to the data 10 highway 17 v~a a buffer memory 7~ and a comm~nication repeating microcomputer 81. The control microcomputer 71 controls ~he operation~ of the ISPN interface un$t, the PS~N interface unit and the extension line telephone set lnterace unit by tran6mitting/receiving control data 15 to/from these interface unl~s through the d~ta hi~hway 17. This control microcomputer 71 al90 ~ontrol~ a tlme switch 83, a con~erence speech circ~lt ~5, etc. The ti~e s~itch ~3 is connected to the speech highway 19 to switch speech channel~. ~he conference speech ~i~cuit 8~ i8 20 conn~cted to the ti~e switch ~ to proces~ ~pe~ch d~ta d~rln~ conference conver6ation.
An MF signal receiver 86 receives d~git slgnal~
outputted from th~ st~ndard telephone 6et ll in the form o m~ltifrequency code (MF slgnal~) through the speech 25 highway 19. In ~he ordinary standard telephone set 11, lt is possible to select any one of MF mode in ~hich digit ~ignal~ are outputted in the form of ~ ~ignals and DP mode in which digit signals are outputted in the form of dial pul~es. In thi~ embodiment, however, an 30 ass~ption is made that the MF mode is 8elec~ed.
Therefore, all d~git signals from the standard telephone ~et 11 are received by the MF signal receiver ~. The MF
signal r~ceiver 86 converts the received diglt ~ignals into pre~etermlned digital codes to tran~mit the~ to the 35 control microcomputer 71.
Flg. 10 show~ the configur~tion of a part of the control ~icrocomputer 71, which relates to pad control, 12 2028~91 In the drawlng, a control signal receiving sect~on 201 rece~ves vario~ control data g~ven rrom the data h~ghw~y 17 to the bu~ 77 via the communication repeating mlcro~omputer ~ nd dlg~t ~ign~l~ given f rom the speech 5 highway lg to the bus 77 via the MF receiver 86, in order to decode these data and signal6.
~ hen ~n outgo;ng call i~ tran~mit~od ~eom the standard telephone set 11 to the IS~ line 3, digit ~ignal~ indicative of a port number which deslgnates the 10 ISDN llne 3 and a channel to be u3ed and indi~t~ve of a telephone number of a called subscriber are ~ran~itted from the g~andard telephone set 11 and received by a control signal receive section 201. On the other hand, when an incoming call is transmltted Erom the ISPN line 3 15 to the standard telephone set 11, control data ~ndlcative of A port number ~hich designates the ISDN line 3 and a channel called and indicative of a telephone number o~ a callin~ subscriber are tran~itted from the IS~N
interface unit 5 to the control signal recelve seetion 20 201. In these ca~e~, the control sign~l recelve sectlon 201 gives the recelved port number to a ~ontrol 6ignal transmit sect~on 215, and the received telephone number to a telephone num~er register 3ection 203 and ~ table searoher 205.
In re~ponse to the given telephone number, the table searcher 205 makes an access to a telephone number-~ubpad number table 207 to sea~ch the given telephone number, Thi~ table 207 i6 formed with a plurallty of area~ where telephone nu~bers are regi6tered and are~s where 30 transmit/reçeive digital subpad nu~ber~ related to the registered ~elephone number~ are registered, re~pectively. In the area~ at whi~h telephone nu~ber~
are registered, the ~reas written as "IN~IVID~AL No." are tho~e at which indlv~dual telephone numbers are registered, and the areas written a~ "NON~R~ISTER~D" are tho~e repre~ent~tive of all the non-regl~tered telephone numbers. Further, "0" ind~cative of turned-o p~d 1B
1~
202879~
regi~tered as an initial value in each area at which a ~ubpad n~mber i~ registered.
In the above-mentioned searching operation, the t~b~e ~earcher ~05 fir~t ~can6 ~IN~IVI~AL No." areas to 5 check wh~ther the given telephone number ~as already been registered. If registered, the table searcher 205 reads the transmlt/receive subpad numbers regl~e~ed with respect ~o the given telephone number ~rom the table 207, and ~end~ the read subpad numbers to a transmit pad 10 control section 211 and a receive pad control sectlon 213. The transmit/receiv~ pad cont~ol sections 2~1 2nd 213 send these ~ubpad numbers to a ~ontrol signal transmit ~ection 215. This control signal transmit section 215 forms pad contrql d~ta including ~hese ~ubpad 15 number~ and the por~ number ~given ~rom the control ~ignal receive ~ection 201), and sends the control data to the IS~N int~rface unit 5. In thi~ way, a ~bpad having a subpad number ~egi~tered with re~pe~t to the given telephone number can be selecte~ within the I8~N
~0 inter~ace unit 5.
Where the given telephone nu~ber is not registered as the result of the above~mentioned search operation, the t~ble ~earcher 205 ~eads the trans~itJrecelve subpad numbers registered w~th respect to the "NON-REGISTERE~"
25 area from the table 207, and ~ends these nu~bers to the tran~mit pad control ~ecti~n 211 and a ~eceive pad control section 213. The trans~it pad contr~l secti~n 211, the recelve pad control ~ection 213, and the c~nt~n~
signal t~ansmit ~ectio~ 21S all operate in quite the sa~e 30 way as de~cribed before. In this way, a ~ubpa~ havin~ a s~bpad nu~ber registered ~ith respect to the "NON-REGISTERE~" can be 6elected within the ISDN inter~ace unlt s, As described abo~e, in response ~o an outgoing call 35 or an incoming call to or Erom the I~N llne 3, a ~ubpad of the p~e~ously-regi~tered number i9 selected to start conversatlon. In case the selected pad is not appropriate, ~t ~5 po66ible to change the ~elected pad during conversation in accordance with the following process procedure-First, digit slgnal~ indi~at~ve a series of5 previou~ly determined digits for re~uesting pad cont~ol are transmitted From the standard telephone 6et, and received by the control signal receive seet~on 201.
Then, the control ~ignal receive se~tion ~10 give6 a pad control ~equest to the ~ubpad number register sectlon Z~9. Since the ~ubpad number register section 20~
previously recelve6 the telephone nu~ber at an outgcing ~all or at an incoming call, in response ~o the pad control request the subpad number register 6ection ~o~
searches an "~NPIVI~AL No." area ~at which the corresponding telephone n~mber is regi~tered) from a table 207, and becomes a set~p statu~ where the -4~bpad nu~be~ reglstered ~ith respect to the telephone number can be rew~itten. Sub3equently, digit siqnals indicativ~
of a new 6ubpad number are trans~itted ro~ the ~tandard ~0 telephone set 11, received by the control s~gnal receive section 201, and then given to the s~bpad nu~ber regi~ter section 209. Thereupon, the subpad number register ~ectlon 20g rewrites the old subpad number already re~stered with respect to the telephone number as a new subpad number. After thi6 rewriting operatlon, the subpad number register section 209 instructs a table sear~her 205 to rewrlte the new s~bpad number. The table sear~her 205 reads the new subpad number from the table 207 and then ~ransmits ~t to a transmit pad control ~ect1on 211 and a receive pad control section ~13. As a result, a new s~bpad of a newly regi6tered subpad nu~ber i~ selected by the ISDN interface un~t 5.
F~rther, ~t i5 also possible to change the subpad number registered in "NON-~EGISTERE~" area of the table 207. This can be done if the above~mentloned spe~ific dlgit signal~ for pad control re~es~ are lnputted fro~
the ~tandard telephone set 11, when the ~tandard telephone ~et 11 is in inco~ing call ~lting ~ode. In thi~ oa~e, since the ~ubpad number register section 209 does not previously recelve ~he telephone number, in re~pon~e to the pad control request the register ~ection 209 i~ set to a setup status where a subpad number registered ~ith re~pect to the "NON-~EGISTERED" area in the table 207 can be rewritten, Proceasing aÇter that is the same as the afore-ment~oned subpad ohange processlng during ~onve~ation.
~he subpad n~mbers regiete~ed ~ith re~pect to the "NON-R~GISTERE~" area can be applied to communication~
th~ough the I~N ~ith all the sub~ribe~ exoept the telephone numbers registered in the "INDIVI~UA~ No. "
area~, As described above, in the key telephone sy~te~ of the present invention, when 6pe~ific subpad n~mbere have been ~egistered from extension telephone ~ets ~in call waiting mode) to the key service u~it, upon an incomlng or outgoing call th~ough the IS~N a subpad having a prev~ously registered 8ubpad number can be automatio~lly sele~ted, and then a gain eo~responding to the subpad is added to the speech ~ignale. ~rther, once a specif~c subpad numbee i6 inputted and registered from the extenelon telephone ~e~ to the key ~ervice unit during conversation between the extension ~elephone set and a spe~ific s~b~crlber through the IS~N, the~eafter upon an incomlng ~all Ero~ a specific ~ub~ceiber or an outgoing call to a ~pe~ific s~bscribe~ through the ISDN, a subpad of a subpad number reg~stered ~or the specific sub6criber can be ~elected automatica~ly. Further, if no subpad number6 a~e registered, pads ar~ au~cmatically tu~ned of~.
In the above embodimen~, the standard telephone set has been adopted as the extension telephone set. Without being limi~ed thereto, it is of oourse poesible to u~e a digital key telephone set. In the ca6e oE a digital key telephone set, however, it lq necessary to provide 2028~9 anothe~ interface unit for dlgital key telephone ~ets within the key service unit, in addition to the ele~ents shown in ~9. 1 o~ in place of the standard telephone interface unit. When the pad control i5 executed by mean~ of the digital key telephone set, the proceqsin9 within the key service uni~ is ~ub6tantially the a~e as tha~ ~n the afo~e-mentioned embodiment, excepting one point that digit s~gnal~ transmitted from the digital key telephone set are inputted to the central contro~ uni~
through the control d~ta highway.
The~e exi~ts a certain key telephone system ~onnectable to a data t~rminal 6uch a~ a per~onal computer as an extension ~tatlon, as well as a telephone set. The present invention is appllcable to such a key telephone system a~ described above~ In thi~ ca~e, however, when the data terminal transmits or receive~
data through the I~DN, the digital pad6 ~hould be turned off to p~otect the data from bein~ damaged.
The present inventlon can be applied not only the key telephone system but al60 the si~ple telephone ~t, a~ ~ar as the telephone ~an be connected to both the analog line and the digital l~ne.
BACKGROUND OF THE INVENTION
The present invention relates to a telephone system and more specifically to a transmission level regulating method for a telephone system connectable to both analog and digital communication networks.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram showing the general system configuration of a key telephone system connectable to both the two networks of ISDN and PSTN;
Figure 2 is a block diagram showing an ISDN interface unit used for an embodiment of the key telephone system according to the present invention;
Figure 3 is a diagram for assistance in explaining the relationship between input and output signals of a transmit/receive digital pad provided in the interface unit shown in Figure 1;
Figures 4(A) and 4(B) are diagrams for assistance in explaining a plurality of subpads provided in the transmit and receive digital pads, respectively;
Figure 5 is a block diagram showing a microprocessor provided in the interface unit shown in Figure 2;
Figure 6 is a block diagram showing a control circuit provided within the interface unit shown in Figure 2;
Figure 7 is a block diagram showing a PSTN interface unit used for the afore-mentioned embodiment;
Figure 8 is a block diagram showing a standard telephone set interface unit of the above embodiment;
~- 20287Y 1 la 20375-675 Figure 9 is a block diagram showing a central control unit of the above embodiment; and Figure 10 is a block diagram showing a microcomputer incorporated in the central control unit shown in Figure 9.
As an example of telephone system of this type, there exist key telephone system connectable to both the integrated service digital network (ISDN) and the (analog) public subscriber telephone network (PSTN). Figure 1 shows a typical system configuration of this telephone system. On a key service unit 1, there are mounted an ISDN interface unit 5 connected to an ISDN
line 3, a PSTN interface unit 9 connected to a PSTN line 7, an extension terminal interface unit 15 connected to a line 13 from an extension terminal 11, etc. These interface units are connected to a control unit 20 for controlling the entire key service unit and channel switching, via a data highway 17 serving as a time-sharing transmission line for control data and a speech highway 19 serving as a time-sharing transmission line for speech PCM (pulse code modulation) codes.
Here, there exists a loss of 4 dB on an average between a subscriber for the PSTN line 7 and a terminal office. In addition, some loss is inevitably produced in a 2-4 line switching circuit and a CODEC (coder/decoder) of an office line (PSTN) interface unit 9. Further, in general the key service unit 1 is so designed that there exists a loss of about -1 dB between the office line (PSTN) interface unit 9 and the individual telephone set interface unit 15.
On the other hand, no loss exists between a subscriber for the ISDN line 3 and a terminal office. Further, the -lb 20375-675 conventional ISDN interface unit 5 performs only signal representation transformation between ternary codes and binary codes, speed conversion between 64 Kb ' :' 20287~ 1 and 2,04~ Mb, multiplexlng, ~eparation, etc. in general, without perfor~lng conver~ion ~ith respect to the ~peech PC~ codes.
A~ a ~esult, ~hen an extension telephone se~ 1 is connect~d to an outslde llne telephonc 3et ~uch a3 an analog telephone set 23, there arise~ the follow~ng problem: Since both the I~D~ and PSTN llne~ are connected to the key ~ervioe unit 1, although telephone conver~ation can be made throuqh any one oE the two line~, there exist6 a a; ~ference in spee~h (t~an~mi~slon) level between the two line~, be~ause the 10~5 through the P8~N line 7 ~5 di~erent ~ro~ th3~ through the ISDN line 3, a~ already expla~ned. In other worde, the ~pee~h le~el differ~ according to the used network, when conver~ation is made with the same per~on. ~he similar differ~nce in the speeoh level occurs between when the extenqion telephone ~et 11 is connected to a digital telephone ~et 21 and when the exten6ion telephone 6et 11 i~ connected to an analog telephone set 23. In addition, the d~f~erence in speech level ~hange~ being s~bjected to the influence oE in~tallatlon conditions of the line~ 3 and 7 and the key 6ervice unit 1.
A~ described above, in a telephone sy~tem conn~c~ed to both the analog and digital communication networks, 2S thQre exists a problem in that the speech ~tran~mi~ion) level differs acco~ding to the connected network and further the level d1f~erence varie~ according to the de~ice in~tallation condi~lon3, thu~ resulting in a difE~culty in malntaining an appropriate ~peech level all the time.
SU~Y OF THE INVENTION
With these problem~ in mind, thereore, lt ia th~
ob~ect of the pre~ent ~nvention to provide a telephone ~y~tem whlch can automatl~ally regulate the ~p~ech level, irrespect~ve o~ the connected networks.
To achieve the above-ment~oned ob~ect, the pre~ent invention provides a telephone ~ystem connectable to both a digital communication network and an analog communication network which comprises:
(a) terminal means provided with functions of transmitting/receiving speech signals;
(b) digital network interface means for providing an interface for communicating the speech signals in digital code form between the terminal means and the digital communication network;
(c) analog network interface means for providing an interface for communicating the speech signals in analog signal form between the terminal means and the analog communication network;
(d) speech level attenuating means for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network, and for adding the selected gain to the speech signals communicated in digital code form between the terminal means and the digital communication network; and (e) gain control means for controlling the gain selection by the speech level attenuating means.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention will be explained hereinbelow with reference to the attached drawings.
The embodiment described below is a key telephone system whose basic system configuration is the same as shown in Figure 1. In more detail with reference to Figure 1, a key service unit 1 comprises an ISDN interface unit 5 connected to an ISDN line 3, a PSTN interface unit 9 connected to a PSTN line 7, and a standard ~`
`` - 202879 1 telephone device interface unit 15 connected to an extension telephone set (e.g. a standard telephone set) 11. These interface units are connected to a central control unit 20 for controlling various calling and s-witching processing via a data highway 17 and a speech highway 19.
Figure 2 shows a configuration of the ISDN interface unit 5 of the present embodiment. In Figure 2, 2-channel speech data and 1-channel control data fed through a receive interface line 31 of the ISDN line 3 are converted from ternary signal to binary signal, and then applied to an interface LSI 37. In this LSI 37, processing related to two different layers (e.g.
separation of speech data (layer 1) from control data (layer 2)) in accordance with programs or other information for controlling the operation of the interface LSI 37, which are stored in a ROM
39 and a RAM 41. The separated speed data are inputted to a ..~
, .
- 5 202879~
multiplexlng ~nd seeial/parallel transforming seçtion 43 via a fi~6t port receive data lLne PlRXP and a second port recei~e data line P2RxD. In the multiplexing and series/parallel tran~orm~ng section 43, 2-ch~nne~ ~peech S data transmitted in serial mode at G4 Kbps a~e multiplexed into 128 Kbps, t~an~formed into p~rallel ~ode, and then fed to a b~s 45. These par~llel speech data ~a-bit PCM ~odes) are inputted to a ~O~ ~i.e.
recei~e digital pad) 4~, and ~-bit PCM codes stored at an address area corresponding to the speech data are read out of the receive digital pad ~PA~) 41 and then fed to a bus 49.
As sho~n in Plg. 3, thi~ receive digital pad 47 iB
constructed in 6uch a ~ay a~ to r~ceive ~peech data represented by 8 lo~eF ~ign~ fican~ 3ddre~ blt~ ~ to ~7, a slgnal ~o~ seleoting a gain rep~esented by t~o middle ~ignificant bl~s A~ and A9, and a signal for controlling the on-off operation oE thi~ pad repre~ented by the most ~ignificant bit lOA. Further, the gain selecting sign~l based on the b~ts A8 and A9 and the on/o~ con~rol signal based on the b~ t lOA are gi~en from a controller 51.
As shown in Fig. 4, thls pad 47 is provided with 8 subpad~ 0000 to 0700, and each subpad include~ ZS6 addre~s areaa ea~h of which can be ~elected in regponse to a ~pee~h data repre~ented by bits AO to A7. The first ~o fourth ~ubpads f~om 0000 to 030~ are selected to produce a galn of 0 dB li.e. no gain) when the logical value of the on/o~f ~ontrol signal rep~e~ented by a bit A10 ~s "0" ~off~. That i~ bit code~ the same a6 the speech data rep~esented by bits A0 to A7 are ~tored at the ~ddress area~ of the subpads, respeotively. The fifth to eighth subpads from 0400 to 0700 are selected to produce one of four different gains of -6, -3, 0, and +3 d~ according ~o the logical val~e o~ the gain selecting slgnal represented by bits AB and A9 when the loglcal value of the on/off control signal A10 i3 ~ on). That i~, 8-blt aode~ obtained by adding each ga~n to the 2028~9 speech data represented by bit~ A0 to A7 ~re stored at the address area~ in the subpads, re6pectively.
~ ith reference to ~ig. 2 again, the ~peech data to whlch a 6elected gain ~s added and read out of the receive digltal pad 47 are inputted to a con~ers~on section 53 to ~onvert the parallel data to 2 ~bp~ serial data, and then superpo6ed upon a designated time slot of an up-l~ne of the ~peech high way 19. In addition, the conve~sion sectlon 53 read~ speech data from a designated t~me ~lot of a d~n-line of the ~peech high way 19. The read spee~h data are converted into parallel data and then ~ent out to a bus ~9. The parallel spe~ch d~ta are inputted to a tran~mit digital pad 55. Thls tran6mit digl~al pad 55 i8 a ROM similar to the receive d~gital pad 47, and re~eives speech dat~ repre~ented by 8 lowe~
eignific~nt addres6 bit6 AO to A7, a gain selecting signal represented by two ~iddle ~ignlficant bl~6 A8 and A9 and an on/off control signal represented by the ~09t ~ignificant bit lOA as shown in ~ig. 3. ~urther, as shown ~n ~19. 4~ the transmit digital p~d 55 c~n select any one o~ ~ains oF O (off), -12, -g, -6 and -3 dB.
Speech data read out of the transmit digi~al pad 55 are inputted to a parallel/~erial conve~tin~ and ~epar~tlng sect~on 59 via a bu~ S7. The parallel/serlal Z5 converting and ~eparating section 59 convert~ 2-ohannèl spee~h data inputted in parallel at 128 Xbp~ speed, respectlvely into serial data, separates these data acoording t~ ~he ch~nnels, and ~ends the data to a fi~st port tran~mit data line PlTXD and a se~ond port tran~mit data line P2TXD. ~he~e ~pee~h data are ~urther ~nputted ~o the interface LSI 37, multiplexed ~ith control data, converted ~nto ternary 6ignals by a drivèr/reo~lver 35, and then ~ed ~o a trans~it inter~ace line 33 o~ the ~SDN
lin~ 3.
On the othe~ hand, oontrol data (selection signals, pro~ess identifier~, eto.) inputted to the in~er~ace LSI
37 ~la the ISDN line 3 are isolated from speech data, 7 202879~
~nputted to a communication repeating microp~oces~or 61, and then t~ansmitt~d to a central control un~t 20 via a data high~ay 17. Fu~ther, program~ and other information for controlling the operation o~ the microproce6~0r 61 are stored in a ROM 63 and a RAM 6~.
The control data given from the central control ~nit to the IS~N interface unit 5 are inputted to the m~croprocessor 61 via the data highway 17~ Some data among control data inpu~ted to the microproce~6or 61 are applled to the ~nterace ~SI 37 ~o as to be m~ltiplexed with speech data bef~re sending out to the transmit interace line 33 via the driver/~ecelver 35. Further, described later, cont~ol data given fr~m the ~entral control unit 20 in~lude data for controll~ng the receive digital pad 47 and the transmit digital pad 55. In response ~o the pad control data, the microp~ocèssor 61 output~ pad control signal~ to the controller 51. The controller 51 set~ three hi~her signlficant ~ddress blts A8, A9 and A10 applied to the re~eive and transmlt dlgital pads 47 and 55 to value~ designated by the pad control s~gnals, so that one subp~d of each of the digital pad6 ~7 and S5 ~9 selected and enabled. Further, a digital P~L (phase locked loop) circuit ~7 and a f~equençy ~ultiplie~ ~9 ~re incorporated to synchronize a clock requency of ~he speech highway 19 with that of the ISDN line 3.
Fig. S show~ a qonfiguration of the micropro~essor ~1 within the ISDN interface unit 5. ln ~e drawing, a oontrol ~i~nal receive se~tion 611 ha~ access to a spe~ific tlme 510t designated by a slot address ~ign~l on a town-highway D~OUT ~f the data highway 17 to rece~ve control data 6upplied fro~ the central control un~t 20, and separates pad control data from other çontrol da~a.
The sepa~qted pad control data are sent ~o a pad control 3S slgnal transmit sec~ion 613, from wh~ch the pad control signal~ are transmitted to the c~ntroller Sl. The othe~
202879~
control data are tran6~itted to the interfa~e LSI 37 via an in~er~a~e ~SI control signal tran~mlt ~ection ~15.
An interface ~SI control signal receive section 617 recelves oontrol data ~rom the interface LSI 37, and 5 ~ends the received control data to a oon~rol ~ignal transmit se~tion 619. The ~ontrol slgnal transmit section 619 ha4 acceEs to a speci~ic t~me ~lot de6ignated by a slot addre6æ ignal on an up-highway DHIN oE ~he data highway 1~ to transmit control data from the 10 interfaoe ~SI 37 to th~s ~ime slo~. The tran~mltted control data are sent to the central control unit 20.
Fig, 6 shows a configuration of a pad c~ntrol related sectlon of the ~ontroller 51 within the ISD~
interface unit S. In the drawing, the pad control 15 signal6 from the microprooes~or 61 are inputted to a ~ 2 swltching section 511. This swltc~n~ sectlon Sll di6crimlnates whether the pad control signal is related to pad control of ~1 channel or B2 channel, and transmit~
pad control signals related to the Bl channel ~o a 20 control ~lgnal receive sec~lon 513a and those related to ~he B2 channel to another control slgnal recelve sect~on 513b, re~pe~tively.
The control signal reoeive sec~on 513a for receiving the Bl-channel related pad control signal 25 obtains pad on/of~-related information from the conteol signals, and further recogni~es a selected subpad number when "on" is ob~ained. The pad on/o~f lnformation ls fed to an A10 controller 515a. The A10 controller 515a forms a Bl cha~nel rel~ted on~off con~rol sign~l and outp~t6 30 the formed ~ontrol signal to ~ne input t~rminal A of a ~electo~ 519. When ~1 channel related pad6 are turn~d on, further a selected subpad number is inp~tted to an encoder 51~a. The en~oder 517a form6 a ~-blt data repre6entative o an input~ed subpad number, and outputs thl3 data to two input terminals Al and A2 of a ~elec~or 521, g 202879~
With respect to the ~2 channel, the same pr~cessing as described above are implemented by ~ contro~ ~gnal recei~e section 513b, an A10 controlle~ 515b and ~n encoder 517b. As a result, B2-channel related on/off control signal is applied ~o the other input ter~inal B
o~ the selector 519. When B2 channel related padR a~e turned on, further a 2-bit data rep~esentative of a ~elected subpad number are appl~ed to two input termlnals 81 and ~ of the selecto~ 521.
The sélector Sl9 output6 an on/off control 6ignal seleoted from one of t~o input terminal~ ~ and B. ~he outputted on/off control sign~l i6 applied to the ~o~t significant address bit Al~ of both the recelve and transmit digital pads 41 and 55. The selector 521 15 outputs a 6ubpad number data ~elected from one pai~ of the input terminals Al, ~2 and B1 and B2. The outputted subpad numbe~ data are added to the succeedlng address b~ts A9 and A8.
A timing signal generating sec~ion 523 divides a 20 frame synchronizlng ~ignal into 1/2 to fo~m a ~ 2 sw~tching signal as shown in ~ig. ~. The fo~med switching signal is applied to the selector termlnal~ SE~
of the two selector3 519 and ~21, respe¢tively. A~ a re~ult, an on/of f con~rol signal and a subpad nurnber data ~5 related to the al channel are ~ele~ted during a fi~t half of each frame, and an on/off control signal and ~
subpad number data rela~ed to ~he B2 channel are selected during a second half o~ each frame. These select~ed signal~ an~ data are applled to addres~ bit~ A10, A9 and 3~ ~8 of the receive and ~ansm~t digital pads 47 and 55, in order to determine each gain rel~ted to the ~1 or ~2 channel~
~ ig. 7 show~ a configuration of the PSTN interface unit 9. An interface circult 91 includ~ng a call signal 3S detec~or g3, a polarity 1nversion detector 95 ~nd a dc ~oop ci~cuit 97 15 connected to the P~TN line 7, ~n ordee to detect ~ call ~ignal from the line 7, the polar~ty -2028~
inverslon of the line 7 and the close/open of a dc loop, and further to 6end dial pulses to the line 7. A codec 99 convert~ spee~h signals fro~ analog to digital or vice versa, which i~ ~onnectet in A~ ~anner to the line 7 wh~n 5 a dc loop is closed by the DC loop circuit 97.
A time 510t a66igner 101 dec~des a timing at whlch the codec 9~ receives or t~ansmits speech d~ta through the ~peech highway 19 on the basi6 of a time 910~ addre~s previou~ly det~rmlned for the codec 9~, a frame 10 synchronlzing s~gnal fro~ the speech highway 19 and a clock, and applies a deter~ined timing signal to the codec 99. The codec ~9 recelves or trans~5ts speeeh d~ta through the speech highway lg within a time period a33igned by the time slot ass~gne~ 101.
A control data co~munication ~i~rocomputer 103 monitor~ dete~tion 6ignals f~om ~he call ~i~nal dete~to~
93 and the pola~ity inversion detector 9S, controls the DC loop circult 97, and receive~ and t~an~mlts various control data related to the call signal detection ~ith 20 respect to the cent~al con~rol unit Z0, the pola~ity invers~on detection, dc loop opening/closing, and the dial pul~e transmi~s~on, etc. through the data high~ay 17.
Fig, B ~how~ a configuration of a standard telephone 25 ~et interfa~e unit 15. A call signal tran~mltter 105 t~ansmlts a call signal (e.g. 16 Hz ac 6ignal) ~upplied from a call signal generato~ 107 to a fitandard telephone ~et 11. A dc voltage supply clrc~it 10~ supplies a pre~r~bed dc voltage to the ~tandard telephone 5et 11 to 30 in~ert the polarlty the~eof, and detect~ the do-loop opening/clo~ing by the standard telephone set 11. A dial detector 111 detects a dial p~lse of the telephone ~et 11 .
A codec 113 converts speech signals from analog ~o 35 dig~tal or vice ~rsa and receive~ and transm~ts spee~h data through ~he speech highway 19 within a time pe~od asslgned by the time slot assigner 115.
-20Z8~91 A control ~ata communication ~icroco~puter 117 control~ the call si~nal transmit/interrupt ~on/off), ~onitors the dc loop opening/closlng, control6 the polarlty invers~on, mon~tors the dial pulse detection 5 re~ult, and ~om~unicate~ control data ~ith the central control unit 20 throu~h the d~ta hlghway 17.
Flg. 9 show~ a ~onfigura~ion oÇ the central con~rol ~nlt 20 of this embodiment. ~he central control unit ~0 lncludes a control microcompu~er 71 connected to the data 10 highway 17 v~a a buffer memory 7~ and a comm~nication repeating microcomputer 81. The control microcomputer 71 controls ~he operation~ of the ISPN interface un$t, the PS~N interface unit and the extension line telephone set lnterace unit by tran6mitting/receiving control data 15 to/from these interface unl~s through the d~ta hi~hway 17. This control microcomputer 71 al90 ~ontrol~ a tlme switch 83, a con~erence speech circ~lt ~5, etc. The ti~e s~itch ~3 is connected to the speech highway 19 to switch speech channel~. ~he conference speech ~i~cuit 8~ i8 20 conn~cted to the ti~e switch ~ to proces~ ~pe~ch d~ta d~rln~ conference conver6ation.
An MF signal receiver 86 receives d~git slgnal~
outputted from th~ st~ndard telephone 6et ll in the form o m~ltifrequency code (MF slgnal~) through the speech 25 highway 19. In ~he ordinary standard telephone set 11, lt is possible to select any one of MF mode in ~hich digit ~ignal~ are outputted in the form of ~ ~ignals and DP mode in which digit signals are outputted in the form of dial pul~es. In thi~ embodiment, however, an 30 ass~ption is made that the MF mode is 8elec~ed.
Therefore, all d~git signals from the standard telephone ~et 11 are received by the MF signal receiver ~. The MF
signal r~ceiver 86 converts the received diglt ~ignals into pre~etermlned digital codes to tran~mit the~ to the 35 control microcomputer 71.
Flg. 10 show~ the configur~tion of a part of the control ~icrocomputer 71, which relates to pad control, 12 2028~91 In the drawlng, a control signal receiving sect~on 201 rece~ves vario~ control data g~ven rrom the data h~ghw~y 17 to the bu~ 77 via the communication repeating mlcro~omputer ~ nd dlg~t ~ign~l~ given f rom the speech 5 highway lg to the bus 77 via the MF receiver 86, in order to decode these data and signal6.
~ hen ~n outgo;ng call i~ tran~mit~od ~eom the standard telephone set 11 to the IS~ line 3, digit ~ignal~ indicative of a port number which deslgnates the 10 ISDN llne 3 and a channel to be u3ed and indi~t~ve of a telephone number of a called subscriber are ~ran~itted from the g~andard telephone set 11 and received by a control signal receive section 201. On the other hand, when an incoming call is transmltted Erom the ISPN line 3 15 to the standard telephone set 11, control data ~ndlcative of A port number ~hich designates the ISDN line 3 and a channel called and indicative of a telephone number o~ a callin~ subscriber are tran~itted from the IS~N
interface unit 5 to the control signal recelve seetion 20 201. In these ca~e~, the control sign~l recelve sectlon 201 gives the recelved port number to a ~ontrol 6ignal transmit sect~on 215, and the received telephone number to a telephone num~er register 3ection 203 and ~ table searoher 205.
In re~ponse to the given telephone number, the table searcher 205 makes an access to a telephone number-~ubpad number table 207 to sea~ch the given telephone number, Thi~ table 207 i6 formed with a plurallty of area~ where telephone nu~bers are regi6tered and are~s where 30 transmit/reçeive digital subpad nu~ber~ related to the registered ~elephone number~ are registered, re~pectively. In the area~ at whi~h telephone nu~ber~
are registered, the ~reas written as "IN~IVID~AL No." are tho~e at which indlv~dual telephone numbers are registered, and the areas written a~ "NON~R~ISTER~D" are tho~e repre~ent~tive of all the non-regl~tered telephone numbers. Further, "0" ind~cative of turned-o p~d 1B
1~
202879~
regi~tered as an initial value in each area at which a ~ubpad n~mber i~ registered.
In the above-mentioned searching operation, the t~b~e ~earcher ~05 fir~t ~can6 ~IN~IVI~AL No." areas to 5 check wh~ther the given telephone number ~as already been registered. If registered, the table searcher 205 reads the transmlt/receive subpad numbers regl~e~ed with respect ~o the given telephone number ~rom the table 207, and ~end~ the read subpad numbers to a transmit pad 10 control section 211 and a receive pad control sectlon 213. The transmit/receiv~ pad cont~ol sections 2~1 2nd 213 send these ~ubpad numbers to a ~ontrol signal transmit ~ection 215. This control signal transmit section 215 forms pad contrql d~ta including ~hese ~ubpad 15 number~ and the por~ number ~given ~rom the control ~ignal receive ~ection 201), and sends the control data to the IS~N int~rface unit 5. In thi~ way, a ~bpad having a subpad number ~egi~tered with re~pe~t to the given telephone number can be selecte~ within the I8~N
~0 inter~ace unit 5.
Where the given telephone nu~ber is not registered as the result of the above~mentioned search operation, the t~ble ~earcher 205 ~eads the trans~itJrecelve subpad numbers registered w~th respect to the "NON-REGISTERE~"
25 area from the table 207, and ~ends these nu~bers to the tran~mit pad control ~ecti~n 211 and a ~eceive pad control section 213. The trans~it pad contr~l secti~n 211, the recelve pad control ~ection 213, and the c~nt~n~
signal t~ansmit ~ectio~ 21S all operate in quite the sa~e 30 way as de~cribed before. In this way, a ~ubpa~ havin~ a s~bpad nu~ber registered ~ith respect to the "NON-REGISTERE~" can be 6elected within the ISDN inter~ace unlt s, As described abo~e, in response ~o an outgoing call 35 or an incoming call to or Erom the I~N llne 3, a ~ubpad of the p~e~ously-regi~tered number i9 selected to start conversatlon. In case the selected pad is not appropriate, ~t ~5 po66ible to change the ~elected pad during conversation in accordance with the following process procedure-First, digit slgnal~ indi~at~ve a series of5 previou~ly determined digits for re~uesting pad cont~ol are transmitted From the standard telephone 6et, and received by the control signal receive seet~on 201.
Then, the control ~ignal receive se~tion ~10 give6 a pad control ~equest to the ~ubpad number register sectlon Z~9. Since the ~ubpad number register section 20~
previously recelve6 the telephone nu~ber at an outgcing ~all or at an incoming call, in response ~o the pad control request the subpad number register 6ection ~o~
searches an "~NPIVI~AL No." area ~at which the corresponding telephone n~mber is regi~tered) from a table 207, and becomes a set~p statu~ where the -4~bpad nu~be~ reglstered ~ith respect to the telephone number can be rew~itten. Sub3equently, digit siqnals indicativ~
of a new 6ubpad number are trans~itted ro~ the ~tandard ~0 telephone set 11, received by the control s~gnal receive section 201, and then given to the s~bpad nu~ber regi~ter section 209. Thereupon, the subpad number register ~ectlon 20g rewrites the old subpad number already re~stered with respect to the telephone number as a new subpad number. After thi6 rewriting operatlon, the subpad number register section 209 instructs a table sear~her 205 to rewrlte the new s~bpad number. The table sear~her 205 reads the new subpad number from the table 207 and then ~ransmits ~t to a transmit pad control ~ect1on 211 and a receive pad control section ~13. As a result, a new s~bpad of a newly regi6tered subpad nu~ber i~ selected by the ISDN interface un~t 5.
F~rther, ~t i5 also possible to change the subpad number registered in "NON-~EGISTERE~" area of the table 207. This can be done if the above~mentloned spe~ific dlgit signal~ for pad control re~es~ are lnputted fro~
the ~tandard telephone set 11, when the ~tandard telephone ~et 11 is in inco~ing call ~lting ~ode. In thi~ oa~e, since the ~ubpad number register section 209 does not previously recelve ~he telephone number, in re~pon~e to the pad control request the register ~ection 209 i~ set to a setup status where a subpad number registered ~ith re~pect to the "NON-~EGISTERED" area in the table 207 can be rewritten, Proceasing aÇter that is the same as the afore-ment~oned subpad ohange processlng during ~onve~ation.
~he subpad n~mbers regiete~ed ~ith re~pect to the "NON-R~GISTERE~" area can be applied to communication~
th~ough the I~N ~ith all the sub~ribe~ exoept the telephone numbers registered in the "INDIVI~UA~ No. "
area~, As described above, in the key telephone sy~te~ of the present invention, when 6pe~ific subpad n~mbere have been ~egistered from extension telephone ~ets ~in call waiting mode) to the key service u~it, upon an incomlng or outgoing call th~ough the IS~N a subpad having a prev~ously registered 8ubpad number can be automatio~lly sele~ted, and then a gain eo~responding to the subpad is added to the speech ~ignale. ~rther, once a specif~c subpad numbee i6 inputted and registered from the extenelon telephone ~e~ to the key ~ervice unit during conversation between the extension ~elephone set and a spe~ific s~b~crlber through the IS~N, the~eafter upon an incomlng ~all Ero~ a specific ~ub~ceiber or an outgoing call to a ~pe~ific s~bscribe~ through the ISDN, a subpad of a subpad number reg~stered ~or the specific sub6criber can be ~elected automatica~ly. Further, if no subpad number6 a~e registered, pads ar~ au~cmatically tu~ned of~.
In the above embodimen~, the standard telephone set has been adopted as the extension telephone set. Without being limi~ed thereto, it is of oourse poesible to u~e a digital key telephone set. In the ca6e oE a digital key telephone set, however, it lq necessary to provide 2028~9 anothe~ interface unit for dlgital key telephone ~ets within the key service unit, in addition to the ele~ents shown in ~9. 1 o~ in place of the standard telephone interface unit. When the pad control i5 executed by mean~ of the digital key telephone set, the proceqsin9 within the key service uni~ is ~ub6tantially the a~e as tha~ ~n the afo~e-mentioned embodiment, excepting one point that digit s~gnal~ transmitted from the digital key telephone set are inputted to the central contro~ uni~
through the control d~ta highway.
The~e exi~ts a certain key telephone system ~onnectable to a data t~rminal 6uch a~ a per~onal computer as an extension ~tatlon, as well as a telephone set. The present invention is appllcable to such a key telephone system a~ described above~ In thi~ ca~e, however, when the data terminal transmits or receive~
data through the I~DN, the digital pad6 ~hould be turned off to p~otect the data from bein~ damaged.
The present inventlon can be applied not only the key telephone system but al60 the si~ple telephone ~t, a~ ~ar as the telephone ~an be connected to both the analog line and the digital l~ne.
Claims (6)
1. A telephone system connectable to both a digital communication network and an analog communication network, comprising:
(a) terminal means provided with functions of transmitting/receiving speech signals;
(b) digital network interface means for providing an interface for communicationg the speech signals in digital code form between the terminal means and the digital communication network;
(c) analog network interface means for providing an interface for communicating the speech signals in analog signal form between the terminal means and the analog communication network;
(d) speech level attenuating means for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network, and for adding the selected gain to the speech signals communicated in digital code form between the terminal means and the digital communication network; and (e) gain control means for controlling the gain selection by the speech level attenuating means.
(a) terminal means provided with functions of transmitting/receiving speech signals;
(b) digital network interface means for providing an interface for communicationg the speech signals in digital code form between the terminal means and the digital communication network;
(c) analog network interface means for providing an interface for communicating the speech signals in analog signal form between the terminal means and the analog communication network;
(d) speech level attenuating means for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network, and for adding the selected gain to the speech signals communicated in digital code form between the terminal means and the digital communication network; and (e) gain control means for controlling the gain selection by the speech level attenuating means.
2. The telephone system of claim 1, wherein the speech level attenuating means is a code conversion memory for receiving the digital code form speech signal as an address signal and reading a digital code previously stored at an address designated by the received address signal, and each digital code previously stored at each address indicates a value obtained by adding the selected gain to each address.
3. The telephone system of claim 2, wherein the code conversion memory includes a plurality of submemories at each address of which a digital code obtained by adding a previously determined gain to each address is stored at each address in such a way that the gain is different for each submemory, and the gain control means controls the code conversion memory so that either one of the plural submemories is selectively enabled.
4. The telephone system of claim 3, wherein the gain control means comprises:
register means for previously registering a select information signal indicative of which submemory to be selected from plural submemories;
reading means for reading the registered select information signal from the register means when communication of the speech signals is made between the terminal means and the digital communication network; and control means for controlling the code conversion memory to enable a submemory indicated by the read select information signal.
register means for previously registering a select information signal indicative of which submemory to be selected from plural submemories;
reading means for reading the registered select information signal from the register means when communication of the speech signals is made between the terminal means and the digital communication network; and control means for controlling the code conversion memory to enable a submemory indicated by the read select information signal.
5, The telephone system of claim 3, wherein the gain control means comprises:
table means for previously registering a select information signal indicative of which submemory to be selected from plural submemories and telephone numbers;
reading means for reading the select information signal from the table means, when communication of the speech signals is made through the digital communication network between the terminal means and a subscriber specified by the registered telephone numbers: and control means for controlling the code conversion memory to enable a submemory indicated by the read select information signal.
table means for previously registering a select information signal indicative of which submemory to be selected from plural submemories and telephone numbers;
reading means for reading the select information signal from the table means, when communication of the speech signals is made through the digital communication network between the terminal means and a subscriber specified by the registered telephone numbers: and control means for controlling the code conversion memory to enable a submemory indicated by the read select information signal.
6. A key telephone system connectable to both a digital communication network and an analog communication network and having a key service unit with speech channel switching means and an extension telephone set connected to the key service unit, comprising:
digital network interface means incorporated in the key service unit, for providing an interface for communicating epeech signals in digital code form between the speech channel switching means and the digital communication network so as to allow communication via the speech channel switching means between the telephone set and the digital communication network;
analog network interface means incorporated in the key service unit, for providing an interface for communicating speech signals ln analog signal form between the speech channel switching means and the analog communication network so as to allow communication via the speech channel switching means between the telephone set and the analog communication network;
speech level attenuating means incorporated in the digital network interface means, for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network and for addlng the selected gain to the speech signals in digital code form communicated between the switching means and the digital communication network; and gain control means incorporated in the key service unit, for controlling the gain selection by the speech level attenuating means.
digital network interface means incorporated in the key service unit, for providing an interface for communicating epeech signals in digital code form between the speech channel switching means and the digital communication network so as to allow communication via the speech channel switching means between the telephone set and the digital communication network;
analog network interface means incorporated in the key service unit, for providing an interface for communicating speech signals ln analog signal form between the speech channel switching means and the analog communication network so as to allow communication via the speech channel switching means between the telephone set and the analog communication network;
speech level attenuating means incorporated in the digital network interface means, for selecting a gain required to compensate for a difference in relative speech signal level between the digital communication network and the analog communication network and for addlng the selected gain to the speech signals in digital code form communicated between the switching means and the digital communication network; and gain control means incorporated in the key service unit, for controlling the gain selection by the speech level attenuating means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP282163/1989 | 1989-10-30 | ||
| JP01282163A JP3085676B2 (en) | 1989-10-30 | 1989-10-30 | Telephone equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2028791A1 CA2028791A1 (en) | 1991-05-01 |
| CA2028791C true CA2028791C (en) | 1994-06-28 |
Family
ID=17648922
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002028791A Expired - Lifetime CA2028791C (en) | 1989-10-30 | 1990-10-29 | Telephone system |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5070524A (en) |
| JP (1) | JP3085676B2 (en) |
| CA (1) | CA2028791C (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5515430A (en) * | 1990-08-28 | 1996-05-07 | Canon Kabushiki Kaisha | Volume controller |
| DE69132460T2 (en) * | 1990-11-29 | 2001-03-15 | Fujitsu Ltd | ISDN interface circuit |
| JPH04208742A (en) * | 1990-12-04 | 1992-07-30 | Canon Inc | Speech level adjusting device |
| JP2744357B2 (en) * | 1991-04-23 | 1998-04-28 | キヤノン株式会社 | Private branch exchange |
| JP2752856B2 (en) * | 1991-08-12 | 1998-05-18 | インターナショナル・ビジネス・マシーンズ・コーポレイション | Telephone service integration device and communication adapter |
| US5495529A (en) * | 1992-11-26 | 1996-02-27 | Nec Corporation | Digital sound level control apparatus |
| US5471527A (en) | 1993-12-02 | 1995-11-28 | Dsc Communications Corporation | Voice enhancement system and method |
| DE59510279D1 (en) * | 1994-03-16 | 2002-08-22 | Siemens Ag | Method for commissioning an interface to be assigned to different transmission paths in a program-controlled communication system |
| FR2733868B1 (en) * | 1995-05-03 | 1997-07-04 | Alsacienne Et Lorraine De Tele | ADAPTABLE MODULAR DEVICE FOR INTERCONNECTING OR COMMUNICATING DIFFERENT LOCAL COMPUTER AND / OR COMMUNICATION DEVICES OR NETWORKS AND A METHOD IMPLEMENTING THIS DEVICE |
| KR0184472B1 (en) * | 1995-11-30 | 1999-05-15 | 김광호 | Multi-subscriber implementation method in keyphone system |
| KR100222433B1 (en) | 1997-02-28 | 1999-10-01 | 윤종용 | Configuration method of network interfacing circuits in isdn key telephone system |
| KR100520161B1 (en) * | 1998-12-30 | 2005-11-24 | 삼성전자주식회사 | Coding conversion circuit between local exchange and ISDN key phone system |
| SE514793C2 (en) * | 1999-05-31 | 2001-04-23 | Ericsson Telefon Ab L M | Procedure and system for line level adjustment between networks |
| AU2002236561A1 (en) * | 2000-12-05 | 2002-06-18 | Jim Bruton | Audio-video transmission via satellite telephone system |
| TW574819B (en) * | 2002-05-23 | 2004-02-01 | Chen Wu Tien | Wireless digital key telephone system |
| JP4586330B2 (en) * | 2002-12-27 | 2010-11-24 | 沖電気工業株式会社 | Voice communication apparatus and voice communication system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62214799A (en) * | 1986-03-14 | 1987-09-21 | Iwatsu Electric Co Ltd | Telephone system |
| JPS6324787A (en) * | 1986-07-16 | 1988-02-02 | Nec Corp | Key telephone system |
| KR880009375A (en) * | 1987-01-17 | 1988-09-15 | 강진구 | Seamos address buffer |
| JPH07110070B2 (en) * | 1989-06-08 | 1995-11-22 | 松下電器産業株式会社 | Digital pad insertion method for ISDN network / terminal |
-
1989
- 1989-10-30 JP JP01282163A patent/JP3085676B2/en not_active Expired - Lifetime
-
1990
- 1990-10-29 CA CA002028791A patent/CA2028791C/en not_active Expired - Lifetime
- 1990-10-30 US US07/605,411 patent/US5070524A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2028791A1 (en) | 1991-05-01 |
| US5070524A (en) | 1991-12-03 |
| JP3085676B2 (en) | 2000-09-11 |
| JPH03143190A (en) | 1991-06-18 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) |
Effective date: 20121202 |