CA2000026C - Dialing confirmation tone output apparatus - Google Patents

Dialing confirmation tone output apparatus

Info

Publication number
CA2000026C
CA2000026C CA002000026A CA2000026A CA2000026C CA 2000026 C CA2000026 C CA 2000026C CA 002000026 A CA002000026 A CA 002000026A CA 2000026 A CA2000026 A CA 2000026A CA 2000026 C CA2000026 C CA 2000026C
Authority
CA
Canada
Prior art keywords
signal
earphone
conversation
producing
response
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 - Fee Related
Application number
CA002000026A
Other languages
French (fr)
Other versions
CA2000026A1 (en
Inventor
Yukio Murata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Publication of CA2000026A1 publication Critical patent/CA2000026A1/en
Application granted granted Critical
Publication of CA2000026C publication Critical patent/CA2000026C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M1/00Substation equipment, e.g. for use by subscribers
    • H04M1/26Devices for calling a subscriber

Abstract

ABSTRACT OF THE DISCLOSURE

A dialing confirmation tone (DCT) output apparatus including a variable attenuator connected between a DCT generator and an adder adding a received voice signal and a dialing confirmation tone. The attenuator attenuates the confirmation tone based on a control signal from a control circuit, The control circuit produces the control signal using a conversation condition signal and a receiving situation signal. The conversation condition signal is provided from a conversation condition detector and indicates whether conversation is taking place or not.
The receiving situation signal is provided from an earphone jack circuit and indicates whether or not an earphone is used for outputting the added signal. The attenuated confirmation tone can be heard while conversation takes place or the earphone is used.

Description

2~ 026 ~ ~`
D I AL I NG CONF I RMAT I ON TONE OUTPUT APPARAIIJS

BACKGROU~D OF THE I NVENT I ON

The pre~ent invention relate~ o a dialing con~irmation tone (DCT) output apparatus and, more partic~larly, to a DCT output apparatuR to be -connected to a receiver of a telephone and to an ; ~
earphone, or a head~et. - -In a conventional DCT output apparatus, a transducer which i~ dedicated to producing a diallng confirmatlon tone is installed in an earpiece of a telephone. This make~ the earplece bulky and reduce~
the clarity of the tone. To avoid these problem~, a receiver of a telephone which outputs a received voice ~ignal could ~e used for emitting the conflrmation - tone. U~ing the receiver, however, makes the user uncomfortable when the conirmation tone is produced during conver~atlon, becau~e the us~r has to keep the ~ receiver close to his ear to listen to the ~ ; ;
f~ conver~ation. Similarly, if an earphone is employed ~ ~ to hear the conver~ation in~tead of the r~ceiver, a ~ loud confirmation tone reache~ the user's ear, making ;~j20 ~ him un'comfortable.

~; SUMMARY OF ~E INVENTION

An ob~ect of the pre~ent invention is, therefore, to provide a generally lmproved dialing confirmation ` tone ~DCT) output apparatue which eliminate~ the ~25 above-mentioned problem~.

Another ob~ect of tho prs~ent invention is to ; ;
provide a ~CT output apparatu~ to be connected to a receiver of a telephone and to an earphone. A ;-! ` ~ . ' .

:, ~

2000026 ~ ~

Yet another object of the present invention is to provide a DCT output apparatus capable of controlling the volume of a dialing confirmation tone.
Still yet another object of the present invention is to provide a DCT output apparatus having a volume control circuit which control6 the volume of a DCT based on the receiving situations of a voice signal and on the condition of conversation.
According to one aspect, the present invention provides a dialing confirmation tone (DCT) output apparatu~ comprising, adder means for adding a voice signal and a DCT signal to produce an added signal; earphone ~ack means for applying ~aid added signal to either a receiver or an earphone and for producing a ~; ~
first ~ituation signal when said added signal is applied to said ~ i receiver and a second situation signal when said added signal is ; - i applied to said earphone; means for detecting the condition of -conversation to produce a firs~ condition signal when no conversation 1~ taking place and a second conditlon signal when ~ conversation i~ taking place; and first means for attenuating said - DCT ~lgnal in respon~e to either said second situation signal or sald æecond conditlon signal. ;~- ~
Accor~ing to another aspect, the present invention ; ; ~~
provides an apparatus compri6ing- means for generating a dlallng ;~
confirmation signal; means responslve to a control signal for attenuatlng said diallng confirmation slgnal; mean~ for addlng an ; input signal and the output of æaid attenuating means; swltching ; means for providing the output of sald addlng means to a receiver when an earphone is not used, for provlding the output of said addlng means to said earphone when sald earphone is used and for ,~
proqucing a situation slgnal when said earphone is not used;~ means '''~`~?~''~'"~
for produclng a condltlon slgnal when conversation is taking place;` and control means for produclng sald control signal in respon~e to said situatlon #lgnal and to sald condltion signal.
.`$''~; Accordlng to yet another aspect, the present invention provldes an apparatus comprlsing: means for selecting flrs~ and "
second current-acoustlc transducers, the output o$ said first -~
tran~ducer being louder than that of said second transducer; means =~

2 -;

2 o o o o 2 6 ! ' ; ~ ~
66446-476 ~
for adding an input signal and a confirmation signal to provide an . - .
added slgnal to the selected one of said first and second transducers; means responslve to a control signal for attenuating said confirmation signal; and control means for producing sald control signal in response to the selected condition of said first ;~
and second transducers and to a condition of conversation ~ :
According to still another aspect, the present invention ~ :
provides a DCT output apparatus comprising: means for generating a dialing confirmation tone; means for adding a received voice ; :
signal and said tone; means connected to said generating means and to said adding means for attenuating said tone in response to a control signal; first detection means for generating a conversation condition signal indicating whether or not ~ ~ ;
conversation is taking place; second detection means f~r - ~ ~
generating a receiving situation signal indicating that a receiver t ~, , of a telephone or an earphone is used for outputting the output of : said adding means; and control means for producing said control ~ :~
signal in response to the combination of said conversation condition and receiving situation signals.
According to a further aspect, the present invention provides a method of controlling a volume of a dialing ~ ~ ~
confirmation signal to be outputted from either a receiver of a . .;: : ;
telephone or an earphone, comprising the following steps of, : : ;~
~ ~ .
selectlng one of a recelver of a telephone and an earphone; adding an input signal and a dialing confirmation signal to provide an added signal to the selected one of said receiver and earphone;
responslve to a control ~ignal, attenuating said dialing confirmation signal; and responsive to the selected condition of :~
, l l sald receiver and earphone and to a condition of conversation, producing said control signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become more apparent from the following ~: description referring to the accompanying drawings, in which~
" '~ ., ~

: 2a :::`
`'`'`' :B '~ ~

2~G,Q26 3 ~ -~
Fig. 1 is a ~chematic block diagram ~howing a DCT
output apparatu~ according to an embodiment of the preisent invention;

Fig. 2 is a ~pecific circuit diagram of DCT
5output apparatus ~hown in FIG. l;

Fig. 3 i~ a ~chematic circuit diagram showing the earphone ~ack circuit of DCT output apparatus shown in Figs. 1 and 2; and Figs. 4A and 4B are time chart~ for explaining lothe operation of DCT output apparatu~ shown in Fig~ 3. , .
DETAI~ DESCR~PTION OF~ REFERRE~ BODIMENTS

In Fig. 1, a dialing confirmation tone (DCT) -~
output apparatu~ 10 includes an adder 12 to which a l5received voice signal i8 ~uppl~ed through a voice :input termlnal 11. The adder 12 al~o receives a DCT ~ `
ignal provided from a DCT generator 20 through a variable attenuator 21. The adder 12 add~ the received two ~ignal~ to produce an added signal. The added ignal is ampllfied by a power amplifisr 13 who~e output i~ delivered from elther a receiver 15 of a telephone or an oarphone 17 through an earphone jack circuit 14. The receiver 15 ~nd oarphono 17 are well ~ ;
, ~ 'known a~ aIternating current-acou~tic wave transducers and the output of receiver 15 1# loud~r than that of t ~earphone 17.

When a plug of earphone 17 i~ in~erted into the .
ack circuit 14, the ~ack circult 14 provides the output of power amplifler 13 to the earphone 17. Whien tha plug 18 not lDserted, on the other hand, the ~ack :-2~0~6 . ., : , . circuit 1~ provid~ the power amplifier 13 output to the receiver 15. Thu~, the ~ack circuit 1~ works as a switch circuit for ~witching between the receiver 15 and the earphone 17.
' ' . ':
The earphone jack circult 14 has another function, to produce a receiving situation signal a indicating whether or not the earphone 17 i~ u~ed for outputting the voice ~ignal. The receiving situation signal _ i8 ~upplied to a control circuit 18. The control circuit 18 al~o receive~ a conversati~n condltlon 3ignal ~ whlch is provided from a convor~ation detection circuit 22 and indicate~
whet~er or not conver~ation is held ~y a telephone.
The detection circuit 22 may detect such a condition lS using the ~tatu~ of a hook switch. Using the -~ receiving ~ituation slgnal a and the conversation ;~ condition ~ignal k. the control circuit 18 produce~ a control signal c to control the attenuation of the variable attenuator 21, i.e., the volume of the DCT
signal.

More s~ecl.fically, four ~ituation~ will be l discu~sed. In the first situation where no conversation is ta~ing placo and the receiver 15 18 used or ou~puttlng a voice signal, the control ~;25~ circuit la cause~ thé variablo attenuator 21 not to ` attenuate the DCT cignal. Thus, the confirmation tone is~delivered from the roceiVer 15 ~o loudly that the user can hear the tone even if he keep~ the receiver 15 away from his ear. In the remaining three situations, the `control circuit 18 cau~es the attenuator 21 to attenuate the DCT signal. The#e three~ situation~ include a #ituation where conversation i~ taking place and the receiver 15 i~

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used, a ~ituation where no conversation is taking place and the earphone 17 is u~ed and a situation where conversation i9 taking place and the earphone 17 '.;
i~ used. Thus, in the remaining three situationi3 the .
confirmation tone is delivered from either the receiver 15 or the earphone 176 ~o ~uietly that the user feeli3 comfortable even if he keeps the receiver 15 close to hi~ ear or he put~ on the '~
earphone 17. '~

lo In Fig. 2, the adder 12 includes an operational amplifier 127 whoae inverted terminal is connected to one end of each of reaistor~ 122!and 123. The oth~r `'~
end of resistor 122 is connected to the voice input . '~
termlnal 11 through a DC-blocklng capacitor 121. The IS other end of resi~tor 123 is connected to the output -~
of attenuator ,21. The non-inverted terminal of ; .
amplifier 127 is connocted. to the ~unction of -~ .. T~
'reoi~tors 125 and 126, ths other ends of which are : connected to a voltage ~ource Vcc and ground, ~:20 ,re~pectively. A feedback resistor 124 is connected ~;~', between the output and inverted terminal of ~ ' .3 amplifler 127. The output of amplifier 127 i~ coupled to the power amplifier 13 through a DC-blocking capacitor 128. ',~ ',`.' ~as ~ The power ampLifier 13 incl~des an operational ','.,,~
amplifier 131 who~e output i8 connected to the jack ~,-,:,.`,'.~, circuit 14 through a DC-blocking capacltor 132. The ~' amplifier 13 1~ powered by the voltage Vcc.

The earphone ~ack circuit 14 include~ ive -~
terminalJ 141 to 145 which are connected to the output "~
of power amplifier 13, the receiver 15, one en~ of a ~',.. ::' re~i~tor 149, the control circuit 1~ and ground, ~

~;~;~:: ,.. '`. ' "'', ,, 2~n~026 -'- 6 re~pectively. The other end of re~istor 149 13 connected to the voltage so~rce Vcc. Jack contacts 146 and 147 are connected to the terminal 141 and 144, respectively. Contacts 150 and 151 ar~
S connected to the terminal~ 142 and 143, re~pectively.
A jacX ~ocket 148 is grounded thro~gh the terminal 145 and accept~ an earphone plug 17.

The control circuit 18 include~ a central proce~sing unit (CPU) 180 and an NPN transistor 184 whose emitter and collector are grounded and connected to a terminal 183 of CPU 180, respectively. A
re~istor 185 i8 connected between the ba~e of transi~tor 184 and the output of earphone jack circult 14. A re~istor 186 i~ connected between the~
ba~e and emitter of transi~tor 104. A re~i~tor 187 i~
.~ connected between the collector of transi~tor 184 and the voltage ~ource Vcc. Terminal~ 181 and 182 of CPU 180 are connected to the attenuator 21 and the torminal 19 of conversation detection circuit 22, i ~o respectively.
.. , , ~ .
The DCT generator 20 include~ a tone generator 201 connected between the attenuator 21 and ground. The attenuator 21 includes an analog witch 211 connected,betweon it~ output and input. A
~25~ ; re~l#tor 212 1~ connected in parallel with the swltch 211. A DC-blocking capacitor 214 i~ in~erted between the ~witch 211 and the DCT qenerator 20. A
',~ ~ re~i~tor 213 is connected between the voltage o~rce Vcc and a control terminal (not ~hownj of analog ~wltch 211. The control terminal of ~wltch 211 i8 al~o connected to the terminal 181 of CPU 180.

~ , 2t3~Q.~6 7 :
In operation, the amplifier 127 adds a voice signal and DC~ signal provided therete through the re~istor~ 122 and 123, re~pectively. The added slgnal -i~ applied to one input of amplifier 131 after it~ DC
s component is eliminated by the capacitor 128. The amplifier 131 amplifieS3 the added signal and provideS~
the amplified ~ignal to the earphone jack circuit 14 through the DC-blocking capacitor 132.

When the earpho~e plug 16 i~ not in~erted into ~o the ~ack circuit 14 as shown in Fig. 1, the contacts 150 and 151 are in contact with the ja~k contacts 146 and 147, re3pectively, 80 that the output of po~er amplifier 13 is fed to the receiver 15 and a high-level ~ignal i~ provided to the control IS circult 18 as a receiving situation signal a (~ee~
Fig. 4A). In this case, the high-level situation signal _ indicates that the receiver 15 d~livers the output of power amplifier 13.
, ~ , . ~, When the plug 16 i~ plugged into the jack circuit 14 as shown in Fig. 3, the positive terminal 161 of plug 16 is brought into contact with the ~ack contact 146 and thu3 one wire 171 of earphone 17 i8 electrically connected to the output of power ampllfler 13~ At the 'oame time, another wlre 172 of earpho~e 17 ls grounded through the negative terminal 160 of plug 16, the plug ~ocket 148 and the torminal 145. Thu~, the output of power ampllfier 13 is outputted from th~ earphone 17.
Moreover, the head 162 of plug 16 ~reaks contact be~ween the/ terminals 143 and 144, BO that a low~
level 3ignal 1B provlded to the central circuit 18 as the recelving BitUation signal ~ (see F~g. 4A). In this caae the low-level ~itu~tion ~ignal a indlcate~

~ ~ . ' '''"' `' ,~, .. :, 2~ Q~6 that the earphone 17 i~ used or outputting the output of power amplifier 13.
. .
When the receiving situation signal ~ high, the translstor 1~4 turn~ on to cau~e the ter~inal 183 to be grounded. Otherwise, the transistor 184 turn~
off to cau~e the terminal 183 to be a high-level.
Thus, the signal a is inverted by the transi~tor 184.
If conver~ation is held, the conver~ation detection circuit 20 provides a high-level condition signal b at the terminal 19 (see Fig. 4B). Otherwise, the -~
detection circuit 20 provldes a low-level condition signal b (also ~ee Fig. 4B). The ~ignal k i~ provided at the terminal 182 of CPU 180.

U~ing the inverted situation ~ignal a and the ~5 conver~ation condition slgnal b, CPU 180 producea a control signal c shown in Fig. 4C. In partlcular, when the signal a is high and the ~iignal k i'3 low, that i~, the receiver 15 i~ used and no conversation is taking place, CPU 180 output~i a high-level signal a~ the ~20 ;~ control signal - Otherwi~e, CPU 180 produces a low-level si~al~asi,the~control aignal c. -When the control ~ignal c 13 high, the analog witchr21~1~ia1^cloeed, ao that no attenuation is added to the DCT ~lgnal.~ On the other hand, when the ; control ~tgnal c is low, the ~witch i8 open, ao that ; - the ~ DCT signal pa~ea the resi~tor 212 to be attenuated (~ee Fig. 4D). The attenuation value i~
given as ~ol;low~

~,i.,'~ , .

.,, ~ . .

2~ 6 g : .,.
where ~l23 and R2l2 are the re~i~tance~ of resistors 123 and 212, respectively. By changing the re~istance~
Rl23 and ~2l2~ therefore, the attenuation value can be changed. Thus, only when no conver~ation is taking ~-place and the receiver 15 i~ connected to the output of power ampliier 13, no attenuat~on i~ added to the DCT ~ignal. In all the other ~ituation~, the DCT
~ignal is attenuated. Accordlngly, uncomfortable DCT
sound cannot be heard from the receiver 15 or earphone 17.
-, -~

.: . : :: ..
~ ~ -,: . . :, ::,` ~ ',",''';

, ~1 !/; I ; I : : '-'.:'.

:, . :: ~

Claims (22)

1. A dialing confirmation tone (DCT) output apparatus comprising:
adder means for adding a voice signal and a DCT
signal to produce an added signal;
earphone jack means for applying said added signal to either a receiver or an earphone and for producing a first situation signal when said added signal is applied to said receiver and a second situation signal when said added signal is applied to said earphone;
means for detecting the condition of conversation to produce a first condition signal when no conversation is taking place and a second condition signal when conversation is taking place; and first means for attenuating said DCT signal in response to either said second situation signal or said second condition signal.
2. An apparatus as claimed in claim 1, wherein said first means comprises:
control means for producing a first control signal in response to said first situation signal and to said first condition signal and for producing a second control signal in response to either said second situation signal or said second condition signal; and attenuator means for attenuating said DCT signal in response to said second control signal and for providing a nonattenuated DCT signal to said adder means in response to said first control signal.
3. An apparatus as claimed in claim 2, wherein said attenuator means comprises parallel connected analog switch and resistor.
4. An apparatus as claimed in claim 1, wherein said earphone jack means comprises:
socket means for accepting and supporting an earphone plug connected to said earphone; and first and second jack contacts coupled to the output of said adder means and said first means, respectively, said first and second jack contacts being in contact with said receiver and a voltage source, respectively, when said earphone plug is not plugged into said socket means and being in contact with said earphone and out of contact with said voltage source, respectively, when said earphone plug is plugged in said socket means.
5. An apparatus as claimed in claim 1, further comprising means connected between the output of said adder means and the input of said earphone jack means for amplifying said added signal.
6. An apparatus comprising:
means for generating a dialing confirmation signal;
means responsive to a control signal for attenuating said dialing confirmation signal;
means for adding an input signal and the output of said attenuating means;
switching means for providing the output of said adding means to a receiver when an earphone is not used, for providing the output of said adding means to said earphone when said earphone is used and for producing a situation signal when said earphone is not used;
means for producing a condition signal when conversation is taking place; and control means for producing said control signal in response to said situation signal and to said condition signal.
7. An apparatus as claimed in claim 6, wherein said control means comprises:
transistor means for inverting said situation signal to produce an inverted situation signal; and CPU means for producing said control signal in response to said inverted situation signal and to said condition signal.
8. An apparatus as claimed in claim 6, wherein said attenuating means comprises:
switch means for passing said dialing confirmation signal in response to the absence of said control signal, said switch means being open in response to said control signal; and resistor means connected in parallel with said switch means for attenuating said dialing confirmation signal.
9. An apparatus as claimed in claim 8, wherein said switch means comprises an analog switch.
10. An apparatus as claimed in claim 6, wherein said adding means comprises: an operational amplifier; a first capacitor receiving said input signal; a first resistor, one end of which is connected to said first capacitor; a second resistor, one end of which is connected to the output of said attenuating means, the other ends of said first and second resistors being connected to each other and being connected to an inverted input of said amplifier; a third resistor connected between said inverted input and the output of said amplifier; a fourth resistor, one end of which is connected to a voltage source; a fifth resistor, one end of which is grounded, the other ends of said fourth and fifth resistors being connected to a non-inverted input of said amplifier; and a second capacitor connected between the outputs of said amplifier and said adding means.
11. An apparatus comprising:
means for selecting first and second current-acoustic transducers, the output of said first transducer being louder than that of said second transducer;
means for adding an input signal and a confirmation signal to provide an added signal to the selected one of said first and second transducers;
means responsive to a control signal for attenuating said confirmation signal; and control means for producing said control signal.
in response to the selected condition of said first and second transducers and to a condition of conversation.
12. An apparatus as claimed in claim 11, further comprising: means for producing a conversation signal when conversation is taking place; and means for producing a non-conversation signal when no conversation is taking place, wherein said selecting means comprises: means for producing a first selection signal when said first transducer is selected; means for producing a second selection signal when said second transducer is selected, and wherein said control means comprises: means for producing an attenuation signal as said control signal in response to either said conversation signal or said second selection signal; and means for producing a non-attenuation signal as said control signal in response to said first selection signal and to said non-conversation signal, and wherein said attenuating means comprises:
means for adding attenuation to said confirmation signal in response to said attenuation signal; and means for adding no attenuation to said confirmation signal in response to said non-attenuation signal.
13. An apparatus as claimed in claim 12, wherein said attenuating means comprises a resistor connected between the output and input of said attenuating means; and a switch connected parallel to said resistor, being closed in response to said non-attenuation signal and being open in response to said attenuation signal.
14. An apparatus as claimed in claim 13, wherein said switch comprises an analog switch.
15. An apparatus as claimed in claim 11, wherein said first transducer comprises a receiver of a telephone and wherein said second transducer comprises an earphone.
16. An apparatus as claimed in claim 15, wherein said selecting means comprises: an earphone plug connected to said earphone; and earphone jack accepting said plug and coupled to said receiver of a telephone, to said adding means and to said control means.
17. An apparatus as claimed in claim 11, wherein said adding means comprises: first and second resistors receiving at one ends thereof said input signal and said confirmation signal, respectively, the other ends of said first and second resistors being connected with each other; and amplifier means for amplifying a signal provided at said other ends of said first and second resistors.
18. A DCT output apparatus comprising:
means for generating a dialing confirmation tone;
means for adding a received voice signal and said tone;
means connected to said generating means and to said adding means for attenuating said tone in response to a control signal;
first detection means for generating a conversation condition signal indicating whether or not conversation is taking place;
second detection means for generating a receiving situation signal indicating that a receiver of a telephone or an earphone is used for outputting the output of said adding means; and control means for producing said control signal in response to the combination of said conversation condition and receiving situation signals.
19. An apparatus a claimed in claim 18, wherein said second detection means comprises: means for accepting a plug of said earphone; means responsive to no acceptance, by said accepting means, of said plug for connecting the output of said adding means to said receiver and producing a first signal as said receiving situation signal; means responsive to the acceptance, by said accepting means, of said plug for connecting the output of said adding means to said earphone and producing a second signal as said receiving situation signal.
20. An apparatus as claimed in claim 18, wherein said attenuating means comprises: a resistor connected to the input and output of said attenuating means; and a switch connected in parallel to said resistor and being closed or open in response to said control signal.
21. A method of controlling a volume of a dialing confirmation signal to be outputted from either a receiver of a telephone or an earphone, comprising the following steps of:
selecting one of a receiver of a telephone and an earphone;
adding an input signal and a dialing confirmation signal to provide an added signal to the selected one of said receiver and earphone;
responsive to a control signal, attenuating said dialing confirmation signal; and responsive to the selected condition of said receiver and earphone and to a condition of conversation, producing said control signal.
22. A method as claimed in claim 21, further comprising the steps of:
producing a conversation signal when conversation is taking place; and producing a non-conversation signal when no conversation is taking place, wherein said selecting step comprises the steps of:
producing a first selection signal when said receiver is selected;
producing a second selection signal when said earphone is selected;
and where said step of producing said control signal comprises the steps of:
responsive to either said conversation signal or said second selection signal, producing an attenuation signal as said control signal; and responsive to said first selection signal and to said non-conversation signal, producing a non-attenuation signal as said control signal, and wherein said attenuating step comprises the steps of:
responsive to said attenuation signal, adding attenuation to said dialing confirmation signal; and responsive to said non-attenuation signal, adding no attenuation to said dialing confirmation signal.
CA002000026A 1988-09-30 1989-10-02 Dialing confirmation tone output apparatus Expired - Fee Related CA2000026C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP246518/1988 1988-09-30
JP63246518A JP2658270B2 (en) 1988-09-30 1988-09-30 Dial confirmation sound output circuit

Publications (2)

Publication Number Publication Date
CA2000026A1 CA2000026A1 (en) 1990-03-31
CA2000026C true CA2000026C (en) 1994-07-05

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CA002000026A Expired - Fee Related CA2000026C (en) 1988-09-30 1989-10-02 Dialing confirmation tone output apparatus

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US (1) US5128991A (en)
EP (1) EP0361496B1 (en)
JP (1) JP2658270B2 (en)
KR (1) KR930001158B1 (en)
CA (1) CA2000026C (en)
DE (1) DE68923238T2 (en)

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JPS61225953A (en) * 1985-03-29 1986-10-07 Nippon Telegr & Teleph Corp <Ntt> Telephone set
JPS61224642A (en) * 1985-03-29 1986-10-06 Iwatsu Electric Co Ltd Dial signal transmission circuit
JPS61283261A (en) * 1985-06-10 1986-12-13 Mitsubishi Electric Corp Dial confirming tone circuit
US4669110A (en) * 1985-10-25 1987-05-26 Itt Corporation Call progress tone system
JPS6386945A (en) * 1986-09-30 1988-04-18 Toshiba Corp Generating device for key input confirming sound

Also Published As

Publication number Publication date
KR930001158B1 (en) 1993-02-19
US5128991A (en) 1992-07-07
CA2000026A1 (en) 1990-03-31
JPH0294954A (en) 1990-04-05
KR900005734A (en) 1990-04-14
EP0361496A2 (en) 1990-04-04
DE68923238D1 (en) 1995-08-03
JP2658270B2 (en) 1997-09-30
DE68923238T2 (en) 1996-01-04
EP0361496B1 (en) 1995-06-28
EP0361496A3 (en) 1991-11-21

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