JPH0358223B2 - - Google Patents
Info
- Publication number
- JPH0358223B2 JPH0358223B2 JP61070522A JP7052286A JPH0358223B2 JP H0358223 B2 JPH0358223 B2 JP H0358223B2 JP 61070522 A JP61070522 A JP 61070522A JP 7052286 A JP7052286 A JP 7052286A JP H0358223 B2 JPH0358223 B2 JP H0358223B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- wire
- door intercom
- telephone
- transmitting
- 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
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 238000001514 detection method Methods 0.000 claims description 5
- 230000003321 amplification Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 3
- 230000002457 bidirectional effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Landscapes
- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Description
【発明の詳細な説明】
「産業上の利用分野」
本発明はボタン電話装置におけるドアホン回路
に関するものである。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a door intercom circuit in a key telephone device.
「従来の技術」
電話機とドアホン子機とが主装置を介して通話
路により接続され、電話機とドアホン子機とが通
話が行なえるようにしたボタン電話装置が知られ
ている。``Prior Art'' A button telephone device is known in which a telephone and a door intercom slave are connected by a communication path through a main device, so that the telephone and the door intercom slave can communicate with each other.
そして、従来のボタン電話装置におけるドアホ
ン回路は、例えば特開昭59−86393「ボタン電話装
置」等に示されるように、双方向の増幅回路を含
んで主装置側に設けるのが普通であつた。ところ
がこのようなボタン電話装置において、最近は主
装置を電話機を一体に構成したいわゆる主装置レ
ス（主装置収容箱の省略）のボタン電話装置が提
案されるようになつた。 The doorbell circuit in conventional key telephone devices was usually provided on the main device side, including a bidirectional amplifier circuit, as shown in Japanese Patent Application Laid-Open No. 59-86393 "Key Telephone Device". . However, recently, among such key telephone devices, so-called main device-less (main device storage box omitted) button telephone devices have been proposed in which the main device is integrated with a telephone set.
しかしながら、主装置を収容した特定の電話機
は大形となるため取扱いに不便であり、これの小
形化が望まれている。そこで、主装置に設けられ
ている増幅回路をドアホン子機側に設けることが
考えられるが、鳴音の発生が問題となつていた。 However, certain telephones that house the main device are large and inconvenient to handle, and there is a desire to make them more compact. Therefore, it has been considered to provide the amplifier circuit provided in the main unit on the side of the door intercom slave unit, but this poses a problem of generating noise.
「発明が解決しようとする問題点」
そこで本発明は従来主装置に設けられていたド
アホン回路における双方向の増幅回路を省略し、
ドアホン子機に受話増幅回路と送話増幅回路を設
け、しかも鳴音が発生しないドアホン回路を得よ
うとするものである。"Problems to be Solved by the Invention" Therefore, the present invention eliminates the bidirectional amplifier circuit in the doorbell circuit that was conventionally provided in the main device,
To provide a door intercom slave unit with a receiving amplifying circuit and a transmitting amplifying circuit, and to obtain a door intercom circuit which does not generate any ringing sound.
「問題点を解決するための手段」
そのため本発明は、電話機とドアホン子機とが
主装置を介して２線の通話路により接続され、電
話機とドアホン子機とが通話が行えるようにした
ボタン電話装置のドアホン回路において、ドアホ
ン子機に少なくとも上記通話路に接続される２線
−４線変換回路と、該２線−４線変換回路の４線
入力端子に接続された送話増幅回路と、４線出力
端子に接続された受話増幅回路と、上記ドアホン
子機を動作状態及び停止状態にするために上記主
装置から上記通話路に送出される直流電流を検出
する電流検出手段と、上記直流電流が送出されて
から一定時間後に出力信号が得られるようにした
遅延手段とを含んで構成し、主装置から上記ドア
ホン子機を動作状態及び停止状態に制御するため
に送出される上記直流電流の送出開始時には上記
遅延手段の出力を送話増幅回路を含む送話系回路
に与え、上記直流電流の送出停止時には上記電流
検出手段の出力を受話増幅回路を含む受話系回路
に与えてそれぞれ制御することにより、２線−４
線変換回路の動作不安定時間帯において上記送話
増幅回路と上記受話増幅回路を介して形成される
音響的帰還ループをその都度遮断するようにした
ことを特徴とするドアホン回路のである。``Means for Solving the Problems'' Therefore, the present invention provides a button that connects the telephone and the door intercom handset through a main device through a two-wire communication path, and allows the telephone and the door intercom handset to make a call. In the door intercom circuit of the telephone device, the door intercom handset includes at least a 2-wire to 4-wire conversion circuit connected to the communication path, and a transmitting amplifier circuit connected to the 4-wire input terminal of the 2-wire to 4-wire conversion circuit. , a receiving amplification circuit connected to a four-wire output terminal; a current detecting means for detecting a DC current sent from the main device to the communication path in order to put the door intercom handset into an operating state and a stopped state; and a delay means so that an output signal is obtained after a certain period of time after the direct current is sent, and the direct current is sent from the main device to control the door intercom handset into an operating state and a stopped state. When the sending of the current starts, the output of the delay means is given to the sending system circuit including the sending amplifier circuit, and when the sending of the direct current is stopped, the output of the current detecting means is given to the receiving system circuit including the receiving amplifier circuit. By controlling 2 lines - 4
This door intercom circuit is characterized in that an acoustic feedback loop formed through the transmitting amplifier circuit and the receiving amplifier circuit is interrupted each time during a period when the line conversion circuit is unstable in operation.
「作用」
上述の構成によれば、ドアホン子機を動作状態
及び停止状態に制御するために主装置から送出さ
れる直流電流の開始及び停止時に生じる２線−４
線回路の動作不安定時間帯において送話系及び受
話系によつて形成される音響的帰環を含むループ
をその都度遮断することができるので、主装置と
ドアホン子機との間にそのための特別な制御線を
設けなくても鳴音が発生しない。"Operation" According to the above-mentioned configuration, the 2-wire-4 signal generated when the direct current sent from the main device starts and stops in order to control the intercom handset into an operating state and a stopped state.
Since the loop including the acoustic return loop formed by the transmitting and receiving systems can be interrupted each time during periods when the line circuit is unstable, there is a No noise is generated even if no special control line is provided.
「実施例」
図は本発明によるドアホン回路を実施したボタ
ン電話装置のブロツク図である。なお、電話機と
一般回線との通話及び電話機相互間の通話のため
の接続動作は従来と全く同じであり、かつ本発明
と直接関係しないので図示は省略した。``Embodiment'' The figure is a block diagram of a key telephone device implementing a door intercom circuit according to the present invention. Note that the connection operations for calls between a telephone and a general line and for calls between telephones are completely the same as in the prior art, and are not directly related to the present invention, so illustrations are omitted.
また、ドアホン子機と電話機との通話のための
主装置における接続動作も従来と同じであるの
で、図における主装置の回路は、本発明によるド
アホン回路の動作を説明するのに必要な部分のみ
を示してある。 In addition, since the connection operation of the main device for communication between the door intercom handset and the telephone is the same as before, the circuit of the main device in the figure is only the part necessary to explain the operation of the door intercom circuit according to the present invention. is shown.
１は主装置、２は電話機、３はドアホン子機で
ある。主装置１にはドアホン子機３を起動するた
めの直流（重畳）電流を送出するスイツチ５及び
音声信号を取り出すための定電流回路６などから
成るドアホン制御回路４が設けられ、該ドアホン
制御回路４は例えば電話機２における押ボタン操
作で駆動するように構成されている。すなわち、
ドアホン子機３からの呼出しに対し、電話機２が
これに応答するため電話機２で押ボタン操作を行
うと、内線通話回路が形成される。この構成につ
いては従来から一般的であるので詳述は省略す
る。７は直流重畳用電源、８は電話機２とドアホ
ン子機３との通話路を形成するトランスである。 1 is a main device, 2 is a telephone, and 3 is a door intercom slave. The main device 1 is provided with a door intercom control circuit 4 consisting of a switch 5 for sending out a direct current (superimposed) current for starting the intercom handset 3, a constant current circuit 6 for extracting an audio signal, and the like. 4 is configured to be driven by pressing a button on the telephone 2, for example. That is,
When the telephone 2 responds to a call from the door intercom handset 3 by pressing a button, an extension call circuit is formed. Since this configuration has been conventionally common, detailed description thereof will be omitted. 7 is a DC superimposition power supply, and 8 is a transformer forming a communication path between the telephone set 2 and the intercom slave unit 3.
ドアホン制御回路４とドアホン子機３とは２線
の線路９で接続されている。１０はダイオードブ
リツジ、１１は電流検出回路、１２は電子化され
た２線−４線変換回路、１３は電源回路で主装置
１から送出される直流を受けて、送話増幅回路１
４及び受話増幅回路１５等に所定の電圧を与える
ように構成されている。１６はスピーカ、１７は
マイク、１８は２線−４線変換回路１２と受話増
幅回路１５間に設けられて受話増幅回路系を一時
的に断（無効）とするアナログスイツチであり、
電流検出回路１１の出力によつて制御される。１
９は送話増幅回路１４の差動増幅器１４ａ，１４
ｂの一方の入力端子に所定の電位（アナロググラ
ンド）を与えるための分圧回路、２０は遅延回路
で、いずれも抵抗とコンデンサによつて構成され
ている。 The door phone control circuit 4 and the door phone handset 3 are connected by a two-wire line 9. 10 is a diode bridge, 11 is a current detection circuit, 12 is an electronic 2-wire to 4-wire conversion circuit, and 13 is a power supply circuit that receives the direct current sent from the main device 1,
4, the receiving amplifier circuit 15, etc., are configured to apply a predetermined voltage. 16 is a speaker, 17 is a microphone, and 18 is an analog switch provided between the 2-wire to 4-wire conversion circuit 12 and the receiving amplifier circuit 15 to temporarily turn off (disable) the receiving amplifier circuit system;
It is controlled by the output of the current detection circuit 11. 1
9 is a differential amplifier 14a, 14 of the transmitting amplifier circuit 14;
A voltage dividing circuit 20 is a delay circuit for applying a predetermined potential (analog ground) to one input terminal of the circuit b, and 20 is a delay circuit, both of which are composed of a resistor and a capacitor.
次に動作について説明する。 Next, the operation will be explained.
前述したようにドアホン子機３から呼出しがあ
つて、電話機２で応答するとドアホン制御回路４
のスイツチ５がONとなる。と直流重畳用電源７
から線路９を介してドアホン子機３に直流が加え
られドアホン子機３は起動される。すなわち、電
源回路１３から送話増幅回路１４、受話増幅回路
１５等に所定の電圧が印加されそれぞれの回路が
動作状態となる。 As mentioned above, when a call is received from the door intercom handset 3 and the telephone 2 answers, the door intercom control circuit 4
switch 5 is turned on. and DC superimposition power supply 7
A direct current is applied to the intercom handset 3 via the line 9, and the intercom handset 3 is activated. That is, a predetermined voltage is applied from the power supply circuit 13 to the transmitting amplifier circuit 14, the receiving amplifier circuit 15, etc., and each circuit becomes operational.
ところで、一般に電子化された２線−４線変換
回路は電源が与えられた直後と電源が断たれた直
後に一時的に動作が不安定となり、送話系の信号
が受話系に漏れるという現象が生じる。従つて受
話系に漏れた音声信号がスピーカから放声されて
再びマイクへ入る音響的帰環を含むループによつ
て鳴音が発生する。 By the way, generally electronic 2-wire to 4-wire conversion circuits temporarily become unstable immediately after power is applied and immediately after power is cut off, causing a phenomenon in which signals from the transmitting system leak to the receiving system. occurs. Therefore, a ringing sound is generated by a loop including an acoustic loop in which the audio signal leaked to the receiving system is emitted from the speaker and then enters the microphone again.
本発明は上述によつて各回路に電圧が印加され
たとき、送話増幅回路１４に設けられた差動増幅
器１４ａの一方の入力端子に加えられる電圧が遅
延回路２０を介して加えられるように構成されて
いるので、通電直後は送話増幅回路１４が飽和動
作となり一時的に増幅作用が行なわれない。 According to the present invention, when a voltage is applied to each circuit as described above, the voltage applied to one input terminal of the differential amplifier 14a provided in the transmitting amplifier circuit 14 is applied via the delay circuit 20. Because of this structure, immediately after energization, the transmitting amplifying circuit 14 becomes saturated and no amplifying action is performed temporarily.
従つて上述した２線−４線変換回路１２の動作
不安定期間に生じる鳴音のループを断とすること
ができる。この断の時間は例えば0.5秒〜１秒程
度に設定すれば十分であり、通話に支障を与える
ことはない。 Therefore, the loop of noise that occurs during the unstable operation period of the 2-wire to 4-wire conversion circuit 12 described above can be interrupted. It is sufficient to set this disconnection time to, for example, about 0.5 seconds to 1 second, and it will not interfere with the telephone call.
一方、アナログスイツチ１８は常時ONとなつ
ていて、主装置１からのドアホン子機３の停止制
御（スイツチ５の開放）があると、線路９を通る
直流電流が断となるので、電流検出手段１１によ
つてこれが検出され、その出力によつてアナログ
スイツチ１８はOFFとなる。すなわち、電源が
断たれることによりその直後に２線−４線変換回
路１２が動作不安定となつて生じる前述した鳴音
のループをアナログスイツチ１８によつて断とす
ることができる。 On the other hand, the analog switch 18 is always ON, and when there is a stop control of the door intercom handset 3 from the main device 1 (opening of the switch 5), the DC current passing through the line 9 is cut off, so the current detection means 11 detects this, and its output turns off the analog switch 18. That is, the analog switch 18 can cut off the above-mentioned ringing loop that occurs when the 2-wire to 4-wire conversion circuit 12 becomes unstable immediately after the power is cut off.
なお、上述の実施例においてはドアホン子機の
起動時にはCRから構成された遅延回路２０を介
して送話増幅回路１４（送話系）を制御するよう
にしたが、CRによる遅延回路に限ることなく、
他の遅延手段でもよい。例えばタイマー回路によ
つて一定時限後に所定の電圧が印加されるように
構成しても同様の効果が得られる。また要は上記
鳴音のループを一時的に断とすればよいから上記
遅延の制御を受話増幅回路１５（受話系）に与え
ても同様の効果が期待できることは容易に理解で
きよう。 In the above-described embodiment, the transmitting amplifier circuit 14 (transmitting system) is controlled via the delay circuit 20 made up of CR when starting up the door intercom handset, but the control is limited to the delay circuit made of CR. Without,
Other delay means may also be used. For example, a similar effect can be obtained by configuring a timer circuit to apply a predetermined voltage after a certain period of time. Furthermore, since the point is to temporarily interrupt the ringing loop, it is easy to understand that the same effect can be expected even if the control of the delay is applied to the receiver amplifier circuit 15 (receiver system).
従つて、停止制御の場合においても同じであ
る。 Therefore, the same applies to stop control.
「発明の効果」
以上説明したように本発明によればドアホン子
機を動作状態及び停止状態に制御するために主装
置から送出される直流電流の開始及び停止時に生
じる２線−４線変換回路の動作不安定時間帯にお
いて送話系及び受話系によつて形成される音響的
帰環を含むループを上記制御に起因させてその都
度遮断することができるので特別な制御線も必要
とせず、ドアホン子機に送話増幅回路と受話増幅
回路を設けることが可能となるので、それだけ主
装置の回路を省略できる。"Effects of the Invention" As explained above, according to the present invention, a 2-wire to 4-wire conversion circuit that occurs when the DC current sent from the main device starts and stops in order to control the door intercom handset into an operating state and a stopped state. Since the loop including the acoustic return ring formed by the transmitting system and the receiving system can be interrupted each time during unstable operation periods due to the above control, no special control line is required. Since it becomes possible to provide a transmitting amplifying circuit and a receiving amplifying circuit in the door intercom handset, the circuit of the main device can be omitted to that extent.
従つて、主装置を電話機と一体に構成した場合
でも比較的小形となり、冒頭で述べた主装置レス
のボタン電話装置に採用して顕著な効果がある。 Therefore, even when the main unit is integrated with the telephone, it is relatively compact, and it is advantageous to use it in the main unit-less button telephone device mentioned at the beginning.
図は本発明によるドアホン回路を実施したボタ
ン電話装置のブロツク図である。
１……主装置、２……電話機、３……ドアホン
子機、１１……電流検出回路、１２……２線−４
線変換回路、１３……電源回路、１４……送話増
幅回路、１５……受話増幅回路、１８……アナロ
グスイツチ、１９……分圧回路、２０……遅延回
路。
The figure is a block diagram of a key telephone device implementing a door intercom circuit according to the present invention. 1...Main device, 2...Telephone, 3...Door intercom handset, 11...Current detection circuit, 12...2 wire-4
line conversion circuit, 13... power supply circuit, 14... transmitting amplifier circuit, 15... receiving amplifier circuit, 18... analog switch, 19... voltage dividing circuit, 20... delay circuit.
Claims (1)
線の通話路により接続され、電話機とドアホン子
機とで通話が行えるようにしたボタン電話装置の
ドアホン回路において、ドアホン子機に少なくと
も上記通話路に接続される２線−４線変換回路
と、該２線−４線変換回路の４線入力端子に接続
された送話増幅回路と、４線出力端子に接続され
た受話増幅回路と、上記ドアホン子機を動作状態
及び停止状態にするために上記主装置から上記通
話路に送出される直流電流を検出する電流検出手
段と、上記直流電流が送出されてから一定時間後
に出力信号が得られるようにした遅延手段とを含
んで構成するとともに、上記遅延手段の出力を上
記送話増幅回路を含む送話系回路に与え、上記電
流検出手段の出力を上記受話増幅回路を含む受話
系回路に与え、上記２線−４線変換回路に電源が
与えられた直後と電源が断たれた直後の一時的動
作不安定時間帯において上記送話増幅回路を含む
送話系回路と上記受話増幅回路を含む受話系回路
を介して形成される音響的帰還ループを上記直流
電流の送出開始時には上記遅延手段の出力によ
り、上記直流電流の停止時には上記電流検出手段
の出力により、それぞれ遮断するようにしたこと
を特徴とするドアホン回路。1. The telephone and door intercom handset are connected via the main device to 2.
In the door intercom circuit of a button telephone device, which is connected by a communication path of a telephone line and enables a telephone call to be made between a telephone and a door intercom handset, a 2-wire to 4-wire conversion circuit is connected to at least the above communication path to the door intercom handset; A transmitting amplification circuit connected to the 4-wire input terminal of the 2-wire to 4-wire conversion circuit, a receiving amplification circuit connected to the 4-wire output terminal, and the above-mentioned door intercom handset in order to put it into an operating state and a stopped state. The current detecting means detects the direct current sent from the main device to the communication path, and the delay means allows an output signal to be obtained after a certain period of time after the direct current is sent out, and The output of the delay means is applied to the transmitting system circuit including the transmitting amplifier circuit, the output of the current detecting means is applied to the receiving system circuit including the receiving amplifier circuit, and the power is supplied to the 2-wire to 4-wire conversion circuit. Acoustic feedback is formed through the transmitting circuit including the transmitting amplifier circuit and the receiving circuit including the receiving amplifier circuit during a temporary unstable period immediately after the power is supplied and immediately after the power is cut off. The door intercom circuit is characterized in that the loop is cut off by the output of the delay means when sending the direct current starts, and by the output of the current detection means when the direct current stops.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7052286A JPS62227249A (en) | 1986-03-28 | 1986-03-28 | Door phone circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7052286A JPS62227249A (en) | 1986-03-28 | 1986-03-28 | Door phone circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62227249A JPS62227249A (en) | 1987-10-06 |
| JPH0358223B2 true JPH0358223B2 (en) | 1991-09-04 |
Family
ID=13433943
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7052286A Granted JPS62227249A (en) | 1986-03-28 | 1986-03-28 | Door phone circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62227249A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101578857B1 (en) * | 2015-03-23 | 2015-12-21 | 김관배 | Food waste treatment apparatus |
| KR101578853B1 (en) * | 2015-03-23 | 2015-12-21 | 김관배 | Food waste treatment apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010178073A (en) * | 2009-01-29 | 2010-08-12 | Panasonic Electric Works Co Ltd | Intercom system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5247925U (en) * | 1975-09-27 | 1977-04-05 | ||
| JPS56131235A (en) * | 1980-03-19 | 1981-10-14 | Nippon Telegr & Teleph Corp <Ntt> | Two-wire/four-wire converter |
-
1986
- 1986-03-28 JP JP7052286A patent/JPS62227249A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5247925U (en) * | 1975-09-27 | 1977-04-05 | ||
| JPS56131235A (en) * | 1980-03-19 | 1981-10-14 | Nippon Telegr & Teleph Corp <Ntt> | Two-wire/four-wire converter |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101578857B1 (en) * | 2015-03-23 | 2015-12-21 | 김관배 | Food waste treatment apparatus |
| KR101578853B1 (en) * | 2015-03-23 | 2015-12-21 | 김관배 | Food waste treatment apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62227249A (en) | 1987-10-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4691336A (en) | Telephone test set having an auxiliary amplifier and speaker for permitting listening to line signals | |
| EP0129208A2 (en) | Handsfree circuit for telephone instrument | |
| JPH0358223B2 (en) | ||
| JP2674645B2 (en) | Cordless telephone with interphone | |
| JPS58206244A (en) | Transmitting and receiving device of cordless telephone | |
| JPS62200852A (en) | Key telephone set used at power failure | |
| JPS63236427A (en) | Cordless telephone set | |
| JP2979056B2 (en) | Cordless telephone with interphone | |
| JPS6349013Y2 (en) | ||
| JPH0383491A (en) | Acoustic echo canceler device | |
| JPH0638512Y2 (en) | Cordless telephone equipment | |
| JPS6292645A (en) | Telephone set circuit | |
| JP3306080B2 (en) | Answering machine | |
| KR0121114Y1 (en) | Hold-on sound circuit for keyphone | |
| JPH0416519Y2 (en) | ||
| JPH01288145A (en) | Howling prevention system at loudspeaker talking end | |
| JPH08107463A (en) | Terminal equipment for magnet type telephone line | |
| JPS63299417A (en) | Cordless telephone set | |
| JPH06104828A (en) | Automatic call transmission reception system for system having terminal equipment connected to earphone microphone terminal and for system utilizing earphone microphone of mobile communication equipment | |
| JPS63240157A (en) | Key telephone set | |
| JPS62147851A (en) | Hand free circuit with singing protection circuit | |
| JPS60174567A (en) | Telephone set | |
| JPS6141258A (en) | Telephone set | |
| JPH0284851A (en) | Telephone set | |
| JPS61140261A (en) | Telephone set |