Published:2009/6/16 22:59:00 Author:May
An intercom using dual-modular wall jacks is shown in this circuit. If the wires are available in the home telephone cable, this system can be installed with little trouble. (View)
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Published:2009/6/16 22:58:00 Author:May
Tro telephones can be used as an intercom by using this circuit. Older style rotary phones that are nonelectronic might work best in this application. Also, handsets only might be powered this way. (View)
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Published:2011/7/13 7:57:00 Author:Michel | Keyword: Telephone Interface Circuit
The automatic recording telephone interface circuit is shown as above.This circuit has the functions of automatic answer and recording.It needs install small tape recorder and solid recording chip.)The circuit is simple and it's needless to open the telephone when static current is less than 20μA.IC1 is a photoelectric coupler.IC2 is a decimal count/distributor and when the fourth ring ends,⑩ feet outputs high level,riggering behind circuit.IC3 is voice circuits which records The honest is absent,please leave a brief message. Primary B uses Φ0.1mm enameled wire to circle 350 turns,the secondary level adopts Φ0.07mm enameled wire to circle 1000 turns.
s (View)
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Published:2011/7/3 2:35:00 Author:Vicky | Keyword: DRAM Integrated Circuit
TMM41256P is a dynamic RAM integrated circuit produced by Toshiba. TMM41256P, together with T6668 constitutes the voice mail system of a dictaphone.
1. Functions and datum of pins
16 pins of IC TMM41256P are in dual-in-line packages.
2. Typical applied circuit
As shown in the picture, typical applied circuit of TMM41256P is identical with IC T6668.
Note: Domestic model no. D41256 is the same with IC TMM41256P, therefore the two part no. can be replaced by each other directly. (View)
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Published:2011/6/4 9:27:00 Author:Michel | Keyword: Anti-theft and Alarm Telephone, Additional Circuit
The author designs an additional circuit for anti-theft and alarm modified by finished telephone afer analyzing.Its material and facture are easy,cost is low,operation is convenient and it's safe and reliable.
Introduction to principleThe circuit is as the picture.K is reed pipe and V1 conducts,the fork reed switches's absorption of drive relays J1 is equal to that the telephone is off-hook . Another control signal amplifies via V2、V3 when it goes through R3 and C3's delay(RC in the picture is about 6s).V4 drive relay J2 is equal to redial key of the control telephone. (View)
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Published:2011/6/3 12:09:00 Author:Michel | Keyword: Optical Coupling, Phone Anti-theft Device Circuit
This transponder will tell your place or contact number to your friend when you friend calls you and you are outside.This transponder is safe and reliable and it will not be disturbed by busy signal.
Work's Principle
The optical coupling phone answer circuit is showed as the pictureThe SRG10A is 10S audio record circuit.Please press SB2 to switch on the power.What you want to tell your friend will be recorded via carried in electret microphone(this is not be drawn in the picture) Please press SB1 when you go out.When it's static state, the clad pipe's collector voltage composed of VT1 and VT2 is around 0.65V and both VL and VT3 are off. (View)
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Published:2011/5/28 1:29:00 Author:chopper | Keyword: wired interphone
We can make a wired interphone easily by using a single chip IC TA7641 in AM radio.The interphone circuit is shown as follows.The interphone is formed by A and B.A is the host,and B is extension.Actually,B is a speaker B2.A and B is connected by twinax cable.When plug XP is inserted to socket XS,the interphone runs.Switch S is a talkback transfer switch.As the following picture,A is in speech state, and B is for obedient state.
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Published:2011/5/8 6:01:00 Author:Rebekka | Keyword: message controller
It is a message controller that uses voice to instead of telephone ring. The circuit is a diargam of message controlle. It uses voice chip ISD1016 to replace telephone ring. The controller can store message, music, a song or some other voice to replace monotonous ring. (View)
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Published:2011/5/8 5:47:00 Author:Rebekka | Keyword: New phone line protection
New phone line protection circuit is shown as below. Telephone wiring in the T and R ends. When someone steal the outside line. BG1 will be conducted. The voltage between T and R is only 2V. The protection will reset automatically after hanging up. When you are calling, press K. If the LED does not light means there is eavesdropping; If the LED lights, it shows that lines are not tapped. (View)
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Published:2011/5/6 4:14:00 Author:Rebekka | Keyword: single chip micro-computer , phone IC
RC8643E is single chip micro-computer phone IC. It can achieve all the featurs of phone except ringing. The in functions and data of integrated circuit are shown in figure 1. (View)
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Published:2011/3/21 1:28:00 Author:Joan | Keyword: Telephone
The figure is Telephone Schematic. (View)
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Published:2011/3/21 1:48:00 Author:Joan | Keyword: Multiparty telephone , switching device
The figure is Multiparty telephone switching device circuit diagram. (View)
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